Photosensitivity is a heightened skin sensitivity or an unusual reaction when your skin is exposed to UV radiation from sunlight. Photosensitivity can occur as a result of medications, a medical condition, a genetic disorder, or even from using certain types of skin care products. Photosensitivity is caused by an abnormal reaction to a component of the electromagnetic spectrum of sunlight and a chromophore within the skin. The most common photosensitivity is to UVA light, but patients can also be sensitive to UVB, ultraviolet radiation, visible light, or wider ranges of radiation. There are two distinct types of photosensitive reactions: photoallergic and phototoxic.
Phototoxicity is a common reaction and usually occurs when a medication is activated by exposure to UV light and causes damage to the skin that can look and feel lie a sunburn or a rash. This can also be triggered by certain ingredients in skin care products. A phototoxic reaction can happen within minutes or after hours of exposure and is usually limited to the skin that has been exposed. Photoallergic reactions on the other hand are a response far less common and occur when UV rays interact with the ingredients in medications or other products applied directly to the skin. This reaction type is classified as type IV hypersensitivity reactions. The body’s immune system recognizes changes caused by sun exposure as a foreign threat. The body produces antibodies and attacks, causing a reaction. A photoallergic reaction can leave you with a rash, blisters, red bumps or even oozing lesions one to three days after application and exposure to the sun.
Photosensitization of the skin can be caused by creams or ointments applied to the skin, medication taken orally or by injection, or by the use of prescription inhalers. In addition to an exaggerated skin burn, itching, scaling, rash, or swelling, exposure to UV light in combination with certain medication may result in skin cancer, premature skin aging, skin and eye burns, allergic reactions, reduced immunity, and blood vessel damage. There are many drugs that can cause photosensitivity. The primary classes of medications that are responsible for photosensitizing reactions include: antihistamines such as diphenhydramine and doxylamine, coal tar and derivatives, contraceptives containing estrogens, NSAIDs such as naproxen and ibuprofen, phenothiazines including perphenazine and promethazine, sulfonamides such as sulfadiazine and acetazolamide, sulfonylureas such as glipizide, thiazide diuretics such as hydrochlorothiazide, tetracyclines such as doxycycline, and tricyclic antidepressants including amitriptyline and imipramine.
Management of photosensitivity involved sun protection and treatment of the underlying disorder. Mainly, photosensitivity reactions are prevented by careful protection from sun exposure and avoidance of exposure to artificial sources of ultraviolet radiation. Protection involves avoiding exposure to direct sunlight, staying indoors, and seeking shade when outdoors, wearing broad spectrum SPF 50 or higher, covering all exposed skin. Sunscreen should protect from UVB and UVA and be water resistant and be generously applied every two hours while outdoors. The mainstay treatment however is wither the withdrawal of the drug, in photoallergic reactions, or reducing the dose of the medication, in phototoxic reactions.
Drug induced photosensitivity is an adverse effect of growing interest. Drug culprits belong to many different classes. Photosensitivity consists of phototoxic or photoallergic reactions in exposure to UV light or visible light. Drugs can increase one's sensitivity to the sun causing increased skin damage. These reactions occur in the UVA range wavelength 315-400 nm and sometimes in the UVB range 315-400 nm or visible light 400-740 nm.
Phototoxic reactions are more common than photoallergic reactions. These reactions are dependent on the dose of the medication and the exposure to light. These reactions usually consist of erythema that can be immediate, delayed or late-onset which is a reaction occurring more than a day after exposure. Immediate reactions are burning of the skin with a prickling sensation or edema (Hoffmann, G. A., & Weber, B.). Long term side effects from photoallergic reactions can be hyperpigmentation of the skin and telangiectasia. These reactions always occur in skin that absorbs UV radiation or visible light. A valence electron shifts to the outer shell, putting the molecule in an excited unstable state. Reactive oxygen species (ROS) are formed which causes oxidation of cellular lipids. Free radicals are also formed and can cause direct cell damage. Drugs that cause phototoxicity have a low molecular weight and planar, tricyclic or polycyclic configurations (Hoffmann, G. A., & Weber, B.). Phototoxicity subtypes include hyperpigmentation and dyschromia, pseudoporphyria, photo onycholysis, eruptive telangiectasia, and pellagra-like reaction (Di Bartolomeo, L. et al.).
Photoallergic reactions occur when the drug absorbs photons and becomes reactive. The drug acts as a hapten in the skin causing a reaction. Langerhans cells present the antigen to T cells via MHC II. This causes a cell mediated type IV reaction. These reactions have a low threshold dose for reaction. These reactions are rare and present as an eczematous rash on the skin. The reaction increases as time goes on and peaks at 48-72 hours. In contrast, phototoxic reactions have maximum clinical manifestations that peak at 24-48 hours of UV exposure. Photoallergic reactions are mainly induced by topical agents rather than systemic agents. Photoallergic subtypes include lichenoid reaction, photodistributed erythema multiforme, and subacute or chronic cutaneous lupus erythematosus (Di Bartolomeo, L. et al.).
Common classes of drugs causing photosensitivity include non-steroidal anti-inflammatory drugs (NSAIDs), antimicrobials, antihypertensives, and antineoplastic agents. Diagnosing phototoxic and photoallergic is important for treatment and prevention. First line treatment always consists of avoiding the offending drug. In many cases, the drug cannot be avoided. Reducing the dose of the drug or reducing time in the sun is the best way to treat these cases. Using sunscreen and clothes that provide shade like hats are also useful to supplement in protecting from UV radiation. Topical steroids can be used for phototoxicity. Topical steroids, antihistamines, and NSAIDs can be used for photoallergic reactions.
A growing area of research is the connection between photosensitizing drugs and photocarcinogenic effects. People that use photosensitizing drugs are at increased risk of developing skin cancer, but it may be due to many reasons. Patients may experience sunburn and not associate it with their medication. It is important that patients are aware of this side effect as it is difficult to avoid the sun and they can easily develop this adverse event.
Resources:
Di Bartolomeo, L., Irrera, N., Campo, G. M., Borgia, F., Motolese, A., Vaccaro, F., Squadrito, F., Altavilla, D., Condorelli, A. G., Motolese, A., & Vaccaro, M. (2022). Drug-Induced Photosensitivity: Clinical Types of Phototoxicity and Photoallergy and Pathogenetic Mechanisms. Frontiers in allergy, 3, 876695. https://doi.org/10.3389/falgy.2022.876695
Hofmann, G. A., & Weber, B. (2021). Drug-induced photosensitivity: culprit drugs, potential mechanisms and clinical consequences. Journal der Deutschen Dermatologischen Gesellschaft = Journal of the German Society of Dermatology : JDDG, 19(1), 19–29. https://doi.org/10.1111/ddg.14314
Photosensitivity is heightened skin sensitivity upon exposure to the sun’s ultraviolet radiation and can be a result of prescription or over-the-counter medication use, a medical condition or genetic disorder, or the use of certain skin care products. Photosensitive reactions are categorized into two types: phototoxicity and photoallergy. A phototoxic reaction occurs upon activation of the oral or topical administration of a drug with UV light exposure, resulting in damaged skin that feels sunburnt or has a rashy appearance. Likewise, this can also be caused by certain chemical constituents found in skincare products. Phototoxicity is the most common type of photosensitive reaction and is dose-related, occurring within minutes or hours of exposure. Generally, the affected area is only associated with sun-exposed parts of the skin. On the other hand, photoallergy is immune-related when the body’s immune system reacts through rashes, blisters, red bumps, or oozing lesions upon several days of UV exposure with ingredients in oral medications or other products applied directly to the skin. A photoallergic response, unlike a phototoxic response, is uncommon, not dose related, and has drug cross-sensitivity. Recognizing the difference between phototoxicity and photoallergy is crucial in determining the most optimal, therapeutic approach to provide symptomatic relief and avoid future complications.
Photosensitivity is caused by a variety of medications, diseases, and skincare products. More specifically, photosensitizing medications act as exogenous chromophores that absorb photons from solar radiation. The absorbed photons cause conformational, structural, or chemical changes in these compounds thereby leading to increased reactivity. Absorbed photons can generate reactive oxidative species (ROS), react directly with DNA, or produce local oxidative stress.
A phototoxic reaction ensues when the exogenous drug molecule absorbs UV radiation or visible light. The molecule, also known as exogenous photosensitizer, then switches from its singlet ground state to a singlet excited state and releases the absorbed energy in several ways: conversion to heat or fluorescence, or energy transfer to other adjacent molecules, for example, oxygen. Transferring energy to oxygen generates reactive oxygen species that cause cellular oxidative damage to lipids or proteins, which explains for the visible skin reactions. Photosensitizers can also covalently bind to DNA and cellular compartments that lead to photooxidation of cells and generate a visible phototoxic skin reaction. Histologic features of phototoxicity include cell necrosis and neutrophilic and lymphocytic infiltration of derma.
Mechanism of Photoallergy:
A photoallergic reaction is a T-cell mediated type IV reaction. Photosensitizing drugs absorb photons upon UV exposure and haptenization occurs. The energized exogenous chromophore binds to protein in the epidermis/dermis, which results in complete antigen formation, known as haptenization. Langerhan cells process the antigen and MHC II complex presents the antigen to naive T cells in the lymph nodes that leads to differentiation of photoallergy-specific T cells. Upon re-exposure to the offending photosensitizing agent, a photoallergic reaction occurs through the release of cytokines, chemokines, and recruitment of inflammatory cells. Histologic features of photoallergy include epidermal spongiosis, vesiculation, exocytosis of lymphocytes into the epidermis, and perivascular inflammatory infiltrates.
To treat a photosensitive reaction, administration of antihistamine and/or corticosteroids is the standard treatment. One of the highly effective therapeutic approaches for photoallergy include prednisone 1 mg/kg/day for 3-10 days or tapered over 3 weeks. Topical corticosteroids include betamethasone valerate 0.1% cream. If the individual is experiencing pain or inflammation, administer NSAIDs, i.e. indomethacin 25 mg TID. As for non-pharmacological therapy, apply a cold compress if appropriate. In a photoallergic response, discontinue the offending agent and do not readminister the photosensitizing agent in the future, and avoid other medications that have similar chemical constituents as the offending agent due to the risk of cross-reactivity. In a phototoxic response, systemic or topical corticosteroids, analgesics, and antihistamines are also used depending on severity. Unlike a photoallergic response, drugs causing phototoxicity may or may not be discontinued based on patient and provider decision. Precautionary measures should be taken in drugs known to cause phototoxicity, such as avoiding sun exposure (if possible), applying broad spectrum sunscreen daily, or wearing long-sleeved clothing, hats, and sunglasses when outside.
References
Kurz, Berandett. “Turn the Light on Photosensitivity.” Journal of Photochemistry and Photobiology, 22 Sept. 2021, www.sciencedirect.com/science/article/pii/S2666469021000567#sec0002.
Lozzi, Flavia, et al. “Latest Evidence Regarding the Effects of Photosensitive Drugs on the Skin: Pathogenetic Mechanisms and Clinical Manifestations.” Pharmaceutics, 17 Nov. 2020, www.ncbi.nlm.nih.gov/pmc/articles/PMC7698592/.
“Photosensitivity.” The Skin Cancer Foundation, 28 Jan. 2022, www.skincancer.org/risk-factors/photosensitivity/.
Photosensitivity can put you at risk for skin damage and skin cancer when exposed to ultraviolet radiation. The more one can learn about photosensitivity, the more one can take precautions to protect their skin. Some individuals may not develop a sensitivity to the sun but if you do, there are steps to prevent photosensitivity from occurring.
Photosensitivity can be caused by UV radiation from tanning a period, OTC medications, genetic disorders, and some selective skincare products. Two types of photosensitivity reactions occur, photoallergic and phytotoxic. photo-toxic is the more common of the two, it occurs when the medication one is taking is activated by UV light and causes a reaction that causes damage to the skin. It usually occurs within minutes or hours after taking the medication and usually occurs in the area where the medication was applied to. Photo allergic is less common and happens when UV rays interact with the ingredients in medicines or other products applied directly to the skin. The body’s immune system recognizes changes caused by sun exposure as a foreign threat. The body produces antibodies and attacks, causing a reaction. A photo-allergic reaction can leave you with a rash, blisters, red bumps, or even oozing lesions one to three days after application and exposure to the sun.
Some helpful ways of avoiding photosensitivity reactions are to ask your doctor or dermatologist about any medications that may have a photosensitivity side effect and to let them know if you have any medical conditions. It is also important to always read warning labels on medication bottles.
If a reaction does occur, you would treat it like a sunburn. You may contact your doctor if you develop a fever with chills, nausea, headache, and weakness, or if your skin blisters. There are also diagnostic tests, such as photo-testing, and photo-patch testing to see if the photosensitive reaction was secondary to a photosensitive reaction.
Always take safety measures, and try to minimize your skin's exposure to the sun (10 AM – 4 PM). Wear protective clothing such as a hat and long sleeves if possible and use sunscreen with an SPF of at least 30.
References:
Photosensitivity. The Skin Cancer Foundation. https://www.skincancer.org/risk-factors/photosensitivity/. Published January 28, 2022. Accessed April 25, 2022.
Photosensitivity is when your skin reacts poorly to the sun/UV light. Photosensitivity can feel a lot like a sunburn, but can also become a rash which is why it is important for patients on certain medications to take precautions and wear protective clothing such as hats, long sleeve shirts, and apply a broad-spectrum sunblock. There are two types of photosensitivity called phototoxic and photoallergic. (1) Phototoxic agents are agents that cause things like sunburn and are typically still continued in patients when the reaction occurs. However, photoallergic agents cause effects such as lesions and are agents that should be avoided since the patient has an allergen to the agent. Toxic photosensitivity is a chemically induced skin irritation that requires light and involves a chemical that affects the skin by topical administration or systemic circulation. The chemical is usually photoactive meaning that when it absorbs light, it produces molecular changes that cause toxicity and results in erythema and blistering 5-15 hours after exposure. Phototoxicity affects the sun-exposed skin only while photoallergy can affect and distribute to the unexposed areas. Photoallergy is not dose-dependent but occurs when a drug or its metabolite induces a cell-mediated immune response due to exposure of longer wavelengths from the sun and is time-dependent thus it can produce a delayed reaction of papular or eczematous contact dermatitis. Photopatch testing is an important diagnostic tool to assess photoallergic reactions.
These abnormal photosensitivity reactions can occur either locally or systemically. Most phototoxic reactions result from systemic administration of medications while photoallergic reactions can be caused by either topical or systemic administration of a drug. Products such as sunscreens that contain PABA or Para-aminobenzoic acid and benzophenone, and topical NSAIDs, can cause such a reaction. NSAIDs, sulfonylureas, and thiazide diuretics are known drugs to cause photoallergic reactions systemically. Drugs such as tetracycline, fluoroquinolones, chlorpromazine, and amiodarone are also known to cause phototoxic effects. Amiodarone is a cardiovascular medication used to treat ventricular arrhythmias and atrial fibrillation. The medication is found to be photosensitive, causing phototoxicity. (2) The method of treatment for agents that are phototoxic is to initially lower the dose of the amiodarone to an effective dose that will also get rid of the photosensitivity reactions. However, if that is ineffective the patient can use systemic corticosteroids or topical antihistamines.(3) Other agents are found to be photoallergic in patients. In this case, the patient should immediately start an antihistamine and a corticosteroid, such as prednisone at 1mg/kg/day for 3-10 days or topical corticosteroid such as betamethasone valerate 0.1% cream. If that is ineffective then the agent is stopped completely and not restarted. It is important to understand that patients who have photoallergic reactions should note that there are other medications with the same components that the patient can be allergic to, such as if a patient is photoallergic to sulfonamide medications they avoid all sulfonamide and sulfur-containing medications.
It is especially important for cancer patients to apply sunscreen and continue to reapply as there are many patients that get severe sunburns even in the darkest of winters triggered by their photosensitivity when on anti-cancer therapy, such as bleomycin. In 2011, the FDA passed a rule that sunscreen can only be labeled as broad-spectrum if it offers UVA protection that is proportional to UVB protection. (4) For cancer patients that are susceptible to photosensitivity, chemical sunscreens may not be the best option as those products can cause a burning sensation on broken skin. Physical sun blockers such as zinc oxide or titanium dioxide reflect or scatter UV radiation and cause less irritation to broken skin.
Overall, it is important to understand the difference between phototoxic and photoallergic signs and symptoms and how to treat the two. In addition, if someone is taking a medication known to cause photosensitivity, such as tretinoin and other medications, they should take the proper precautions to protect their skin from the harmful reactions that can occur. Lastly, photosensitivity is a serious side effect that should be considered when taking certain medications, and if one knows that they will be exposed to sunlight and photons then they should either switch to a medication that is not photosensitive or protect themselves from experiencing its effects when doing so.
References:
Epstein JH. Phototoxicity and photoallergy. Semin Cutan Med Surg. 1999;18(4):274-284. doi:10.1016/s1085-5629(99)80026-1
Redness. Itching. Hives. The first thought that comes to my mind when I hear of these symptoms is allergies. Allergies are associated with rash and hives so when a person experiences an allergic reaction, they experience these symptoms. Photosensitivity is known as sun allergy. A person’s skin can be sensitive to the ultraviolet (UV) radiations from the sun or tanning beds leading them to experience such symptoms. Photosensitivity can be induced through certain medications, diseases and medical conditions as well as certain skin care products. Common areas of the skin that can be exposed to UV rays are the face, ears, neck, back of the hands, arms, and at times on the feet and lower parts of the legs.
There are two different types of photosensitive reactions: phototoxic and photoallergy. Phototoxic is the more common photosensitive reaction that occurs. This reaction can occur from certain medications whether it is oral or topical formulation as well as certain ingredients in the skin care products. These certain medications and ingredients can become activated by the UV rays of the sun or tanning beds. This means that if you take these medications or apply certain products and then decide to go for a walk with shorts and a tank top, then your skin might have a reaction by being out in the sun. It can feel like a sunburn and your skin can become blistered, feel itchy, etc. A phototoxic reaction can occur right away but at times it can also occur hours after the exposure to the UV rays have occurred. In phototoxic reactions, it is limited to the area of the skin that has been exposed.
Photoallergic is a less common photosensitive reaction that occurs and it occurs when UV rays interact with ingredients of medications or skin products that are directly applied on the skin. Common topical formulations can be such as creams, lotions, and gels. A photoallergic reaction is similar to when a person has a cold. It starts off with the body noticing that there are foreign substances and then the body’s fighter cells try to fight those substances off so that the body can go back to being normal and healthy. In the process of fighting off a cold, you notice symptoms such as a cough, mucus production, fatigue and more. Similarly, when a person experiences a photoallergic reaction the body’s fighter cells notice that the UV rays are harming the skin so the body tries to fight them off resulting into a person experiencing symptoms such as blisters, rash, and at times oozing lesions. This can occur from one up to three days after the topical application and exposure to the UV rays. The Skin Cancer Foundation has provided a detailed list of medications that can cause photosensitivity as a side effect as well as list of diseases that can cause photosensitivity. Certain skin care products such as retinols, benzoyl peroxide, vitamin C and more may also cause photosensitivity which is why it is crucial to apply sunscreen especially when using these products.
It is important to minimize exposure to UV rays to help protect against the harmful effects that can be caused by them. Wearing a brimmed hat as well as sun-protective clothing such as long sleeves and tight clothes can help protect the skin. It is also crucial to apply sunscreen SPF 30 or higher at least 30 minutes prior to UV ray exposure. Apply on all areas that will be exposed and make sure to reapply sunscreen every 2 hours. Lastly, make sure to visit a dermatologist and follow-up to ensure that the skin is healthy.
“Photosensitivity.” The Skin Cancer Foundation, 27 May 2021, www.skincancer.org/risk-factors/photosensitivity/.
“Photosensitivity Report - Medications.” The Skin Cancer Foundation, 26 Jan. 2021, www.skincancer.org/risk-factors/photosensitivity/medications/.
“Diseases Related to Abnormal Photosensitivity Responses of the Skin.” The Skin Cancer Foundation, 19 June 2020, www.skincancer.org/risk-factors/photosensitivity/diseases/#1565202675317-18826a83-e996.
Photosensitivity occurs when the skin’s reactivity to light and the sun is increased. Various medications have this as a warning or precaution when taking it. Lots of antibiotics, for example, will include a sticker telling patients to stay out of the sun and wear sunscreen while taking the medication. Photosensitivity can either be photoallergy or phototoxicity. Photoallergy is rare, and occurs when exposure to UV light turns the drug into a hapten and causes it to act as an allergen, causing an immune response. This response can look like hives, erythema and dermatitis, and can spread to other parts of the body that weren’t exposed to the light. This reaction usually does not occur immediately after exposure, and often has a latency period of 23-72 hours. This reaction is not dependent on the dose of the medication itself.
This is in contrast to phototoxicity, which typically occurs quickly after exposure to UV light and is dose dependent. This reaction is much more common and presents more as severe sunburn, with skin peeling, pain and a feeling of skin burning. In this scenario, the medication absorbs the UV light and acts as a toxin, causing damage, but only on the parts of the skin that was exposed. Most phototoxic drugs are activated by UVA light rather than UVB, similar to photoallergic drugs as well.
Besides antibiotics, some other medications that can cause this reaction include NSAIDs, diuretics, anticonvulsants, anti-diabetic agents, and cardiovascular agents. When patients are on these medications, a huge emphasis should be placed on preventing a photosensitivity reaction. If appropriate for the medication, they can be taken at night instead, during a time where sunlight exposure would be minimal and lower concentrations of drug would be present in the body during daylight. As pharmacists we can also let our patients know that the sun is usually strongest between 10 am to 4 pm, and that cloud cover does not mean no risk of sun exposure. They can pick up a sunscreen that is SPF 15 or 30 that is broad spectrum and water resistant.
If a photosensitivity reaction does occur, treatment would be based on severity and might include cold compresses, topical/systemic corticosteroids, or topical analgesics. For both phototoxic and photoallergic reactions, the offending drug or chemical causing exogenous photosensitivity should be discontinued whenever possible. Topical anesthetics should be avoided because of the possibility of a contact allergy. For more severe reactions, systemic corticosteroids may need to be continued for 2 to 3 weeks.
1. Craig A Elmets, MD. Photosensitivity disorders (photodermatoses): Clinical manifestations, diagnosis, and treatment. UpToDate. Nov 2019.
Photosensitivity is a reaction that occurs on the skin when it is exposed to light. It can be further classified as a photoallergic or a phototoxic reaction. Photo allergic reactions are a rare immunological response that is not dose-related and usually occurs after repeated exposure to a drug. Light causes the drug to act as a hapten in the body, this triggers a hypersensitivity immune response within the body and leads to a skin reaction. This skin reaction can be anywhere on the body and is a delayed reaction so can take from 24-72 hours to appear on the skin.
Phototoxic reactions happen when a drug absorbs UVA light and causes cellular damage. The reaction is usually dose dependent but does not demonstrate cross-sensitivity. A skin reaction occurs only on the areas exposed to sunlight and can appear as a severe sunburn. The skin reaction leads to peeling of the skin, pain, and a burning sensation.
There is a multitude of drugs that can have a side effect of causing photosensitivity. Big medication classes including antibiotics (fluoroquinolones, tetracyclines, and other antibiotics including nitrofurantoin, and sulfamethoxazole), NSAIDs (naproxen, ketoprofen, and piroxicam), diuretics (furosemide and hydrochlorothiazide), anti-diabetic agents (glipizide, glyburide, and tolbutamide), and anticonvulsants (carbamazepine and lamotrigine) are known to cause photosensitivity. The best way to manage drug-induced photosensitivity is to prevent the reaction from happening. Although photoallergic reactions cannot be prevented, precautions can be taken to precent phototoxic reactions from occurring. Patients taking medications need to be counseled by the pharmacist to optimally decrease the chance of this reaction. Limitation of sun exposure and well as wearing sunscreen daily is a great counseling point when talking to patients picking up these medications at the pharmacy. If possible, it is also encouraged to take these medications at night. This allows most of the medication to be metabolized and excreted by the body before the sun peaks between the hours of 10 am and 2 pm. Choosing a broad spectrum sunscreen with SPF 15 or higher is strongly encourages any time of year but it is especially encouraged when patients are on medications with a high incidence of photosensitivity.
If the photosensitive reaction occurs the medication should be discontinued. If a photoallergic reaction is occurring, the patient should not try to reintroduce this medication once the rash has resolved. If a phototoxic reaction is occurring, the patient may reintroduce the medication once the reaction has resolved as long as they take extra precautions to avoid sun exposure.
Applying a cool compress, applying a topical or taking a systemic corticosteroid, or applying topical analgesics to decrease some of the discomfort from the rash. In some cases, it may take weeks or months for the entirety of the reaction to resolve.
Photosensitivity occurs when there is increased sensitivity of light on the skin that results in an abnormal red and painful change on the skin’s surface. Photosensitivity can also occur to the patient’s eyes and cause redness in the area. The types of photosensitivity include photo allergy and phototoxicity. Phototoxicity is more common than photo allergy and is a nonimmunological reaction that presents with erythema or redness that looks like a sunburn on a patient’s body. On the other hand, photo allergy presents as urticaria and is an immunological reaction that causes antigens to form in the body causing a delayed type hypersensitivity reaction. Both of these can occur due to side effects from different medications and drug classes. Photoallergic reactions generally occur 24-72 hours after the patient is exposed to the light while phototoxic reactions are likely to occur within minutes to hours after light exposure. Medications that can cause this phenomenon include many different antibiotics like doxycycline, sulfamethoxazole with trimethoprim (Bactrim) and ciprofloxacin. Non-steroidal anti-inflammatory drugs (NSAIDs) like naproxen and ibuprofen, diuretics like furosemide, cardiovascular regulating agents like amiodarone and sulfonylureas for diabetes all are medications that can result in photosensitive reactions. Pharmacists can contribute to the managing of side effects due to their comprehensive knowledge of medications. They as health care professionals can help aid patients prevent photosensitivity reactions by counseling patients to have little to no contact with sun light, especially at peak sun hours between 10am and 2pm when this side effect is a fairly common occurrence. If a patient is to have sunlight contact, he or she should be applying sunscreen 15 to 30 minutes prior to sun exposure with SPF that is at least SPF 15 that is also broad spectrum sunscreen covering both UVA and UVB light rays. Reapplication of sunscreen should also be stressed every 2 hours the patient is exposed to sunlight after the initial application. Another important counseling point is that if the photosensitivity is due to medications, a pharmacist can suggest taking these medications at night so that in the day the drug is less concentrated in the patient’s body. Aside from these prevention techniques, if a patient starts to actually experience the photosensitivity reaction there are ways to manage it. Pharmacists can counsel patients to use cool compresses, use topical or systemic steroidal agents to control inflammation and itching such as over the counter hydrocortisone cream or recommend systemic steroids or a stronger topical cream to the patient’s physician to prescribe. The patient should also use topical or systemic analgesics if they are experiencing any pain. Many patients do not experience a photosensitive reaction the first time they take the causing medication because there is a latency period of developing this side effect. The reaction also is not dose dependent and depends more on how long the patient is taking the medication. Should this reaction occur, it is recommended to discontinue the medication altogether since it is not dose dependent and the patient should be started on a medication of a different class to avoid said reaction again. In some cases of severe reactions resulting in heavy skin burning and peeling, it can take as long as a few weeks to months for the reaction to fully go away. Therefore, counseling the patient is key in order to prevent these dangerous reactions from occurring in the first place.
Reference:
Dubakiene R, Kupriene M. Scientific problems of photosensitivity. Medicina (Kaunas). 2006;42(8):619-24. PMID: 16963827.
Photosensitivity disorders refer to the dermatological response after exposure to ultraviolet (UV) radiation or phototoxic agents. There are two main reactions: phototoxicity and photoallergy.
Phototoxicity occurs more frequently with a quicker onset from minutes to hours after exposure to the offending agent, and is more likely to be drug-induced. It occurs when the offending agent exceeds the threshold concentration and generally requires large amounts in order to cause a reaction. Phototoxicity reactions typically present as exaggerated sunburns. Likely culprits include: tetracyclines (especially doxycycline), hydrochlorothiazide, sulfonamides, metformin, fluoroquinolones, NSAIDs (especially ketoprofen), phenothiazines, amiodarone, retinoids, St. John’s wort.
Photoallergy is a delayed-type immunological reaction caused by repeated exposure to small amounts of an offending allergen. After the first encounter, the allergen changes its antigenicity in response to UV radiation, and upon a repeat exposure, will initiate an allergic reaction. Photoallergic reactions typically present with pruritis, eczematous eruptions in sun-exposed areas of skin that develop 24-48 hours after exposure. Likely culprits include: sunscreens, topical NSAIDs (especially diclofenac), fragrances, phenothiazines, antimicrobial agents, quinolones, sulfonamides, systemic NSAIDs (especially ketoprofen).
In both cases, treatment mainly consists of identifying and discontinuing the offending agent, as well as providing supportive care. In severe cases, symptomatic relief with topical or systemic corticosteroids and/or topical analgesics may be considered. Prevention is also stressed, as these reactions may persist for weeks to months, even after the discontinuation or tapering of the offending agent. Sunscreens with sun protection factor (SPF) 15 or greater are recommended for daily use prior to any sun exposure, as well as sun avoidance and sun-protective clothing.
References
Blakely KM, Drucker AM, Rosen CF. Drug-Induced Photosensitivity—An Update: Culprit Drugs, Prevention and Management. Drug Safety. 2019;42(7):827-847. doi:10.1007/s40264-019-00806-5.
Marneros AG, Bickers DR. Photosensitivity and Other Reactions to Light. In: Jameson J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J. eds. Harrison's Principles of Internal Medicine, 20e New York, NY: McGraw-Hill
Photosensitivity can be separated into two categories: photoallergy and phototoxicity. Both are caused by the skin’s increased reactivity to light. Common medications that are photosensitizers include antibiotics (ciprofloxacin, doxycycline, tetracycline), NSAIDs, diuretics (furosemide, HCTZ), anticonvulsants (carbamazepine, lamotrigine), antidepressants (amitriptyline), and cardiovascular agents (amiodarone, nifedipine) just to name a few. Photoallergy is a rare reaction and it produces an immunologic response resulting in urticaria, erythema, and dermatitis. It usually occurs 24-72 hours after light exposure and can spread to other areas that were not exposed to light. Phototoxicity is more common and it mimics a severe sunburn, with skin peeling, pain, and a burning sensation. Unlike a photoallergy, it is only present on the skin that is directly exposed to light and occurs within minutes to hours of post light exposure. Prevention is key and when patients are at risk for photosensitivity they should minimize their exposure to sunlight. This can be done by wearing protective clothing, using a broad spectrum sunblock with an SPF of 15 or higher, and staying inside or in the shade when sun ray’s are the strongest, between 10 am and 2 pm. It may take weeks or months for a reaction to disappear but it can be treated by symptom management: cool compresses, topical or systemic corticosteroids, and topical analgesics. If a medication is the cause of this reaction and persists or gets worse the drug may be stopped or switched to a less photosensitizing agent or the dose may be reduced.
Photodynamic therapy (PDT) is a two-step treatment where a drug that acts as a photosensitizer is administered to specifically target a diseased tissue, followed by illumination with visible light to activate the drug and destroy the target tissue. It was developed for the treatment of cancer and precancers. The visible light that can be used for PDT varies: coherent light sources (lasers and light-emitting diodes, incoherent sources (broadband lamps), and natural sunlight. However, only validated light sources can be recommended, and two are FDA approved: BLU-U Blue Light Photodynamic Therapy Illuminator 400 nm and (red) BF-RhodoLED 635 nm. PDT has been used to treat actinic keratosis, basal cell carcinoma, and squamous cell carcinoma in situ (Bowen disease). Approval for treatment varies from country to country. Like any treatment it is important to implement safety measures. Retinal damage from the visible light has been seen and it may cause age-related macular degeneration, therefore appropriate goggles that block either blue or red light should be worn during the illumination process. Use of other photosensitizing agents should be used with caution and it may be recommended that certain medications be stopped one to two weeks prior to PDT if possible, such as tetracycline. PDT is known to improve the appearance of hypertrophic scars. After treatment patients are told to stay inside during daylight and to avoid bright indoor light for 48 hours after treatment. If the skin is irritated or pruritic, a topical corticosteroid can be used and cold compresses can be applied for comfort.
Many common drugs like antibiotics, NSAIDs, and anti-diabetic medications can cause photosensitivity, which is an adverse reaction that gets overlooked in many cases. Some specific medications that can cause a photosensitive reaction include amiodarone, nifedipine, furosemide, naproxen, amitriptyline, hydrochlorothiazide, ciprofloxacin, doxycycline, tetracycline, carbamazepine and sulfamethoxazole. It is important to note that there is a difference between photosensitivity, photoallergy and phototoxicity. Photosensitivity is when the skin has an increased reaction to sunlight. This can be further broken down into two categories: photoallergy and phototoxicity. Photoallergy presents as a rare reaction induced by the sun when a drug is the allergen. When ingested, the drug acts as a hapten and when bound to the antigen produces an allergic immunologic response. This reaction presents with urticaria, erythema, and dermatitis. This reaction exists 24 - 72 hours after exposure to UV light. Many patients don’t experience something the first time taking the drug due to a latency period. This reaction is also independent of the dose. Phototoxicity on the other hand is a little different where it occurs more often and does not spread. It presents as a severe sunburn with a painful and burning sensation. The skin will eventually begin to peel as with any sunburn. The onset of symptoms happens much more frequently with minutes to hours after sun exposure. And unlike a photoallergy, it is dose dependent. Degrees of treatment rely heavily on prevention. Patients should be advised to minimize their exposure to sunlight and take their medications at night. When presented with a painful phototoxic or photoallergic reaction, the treatment is symptom based and depends on severity. Some of the treatment options include cool compresses, topical or systemic corticosteroids, and topical analgesics. In some cases it may take as long as weeks to months for a reaction to subside. The offending drug can then be discontinued and switched to another agent; or the physician may choose to continue with the same medication at a lower dose.
Natanova, Marina “ Drug Induced Photosensitivity” APPE presentation 2017
Photosensitivity refers to the skin’s increased reactivity to light exposure. This can present as a side effect of drugs. The PowerPoint discusses two drug-induced photosensitivity disorders: phototoxicity and photoallergy. Some common photosensitizers include antibiotics (fluroquinolones, tetracyclines, bactrim), anticonvulsants (carbamazepine, lamotrigine), NSAIDs, diuretics (furosemide, hydrochlorothiazide), etc.
Phototoxicity is the more common of the two disorders. It is a nonimmunological reaction that usually presents with erythema resembling a sunburn, which usually peels within a few days. Photoallergy is a less common, immunological reaction. UV light exposure creates an unstable hapten, which can bind to macromolecules to form an antigen capable of causing a delayed-type hypersensitivity reaction. It can present with urticaria or as a pruritic eczematous dermatitis. It differs from a phototoxic reaction in that it is not dose-dependent and can spread to areas that were not exposed to the sun. Some patients may even develop a condition known as “persistent light reaction”, which is a hypersensitivity to light even after the offending agent is discontinued. Photoallergic reactions typically occur 24-72 hours post light exposure, while phototoxic reactions occur within minutes to hours post exposure.
The first step of managing a drug-induced photosensitivity reaction is identifying the offending agent and either discontinuing or lowering the dose based on severity. There’s also a strong emphasis put on prevention by minimizing sun exposure and applying broad-spectrum sunscreen. Sunscreens should be SPF 15 or higher, applied 15-30 minutes before going out, and reapplied at least every 2 hours while in the sun. Treatment focuses on symptom management with use of cool compresses, topical or systemic corticosteroids, and topical analgesics chosen based on severity. Some reactions may take weeks or months to resolve. For photoallergic patients with persistent light reaction, an immunosuppressive drug, such as azathioprine, may be necessary.
Reference:
Marneros AG, Bickers DR. Photosensitivity and Other Reactions to Light. In: Jameson J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J. eds. Harrison's Principles of Internal Medicine, 20e New York, NY: McGraw-Hill.
Photosensitivity is when your skin’s sensitivity is increased when it comes in contact with light. There are different types of photo sensitivities: photoallergy and phototoxicity. A lot of times patients experience this due to the various different medications they are taking. Hence, it is very important for us as pharmacists to counsel patients on such medications to help prevent them from experiencing this. Medications that can cause these reactions are many different classes. A few more commonly used medications such as antibiotics (ciprofloxacin, doxycycline, tetracycline, bactrim), NSAIDs, Diuretics, CV agents (amiodarone, nifedipine), anti-diabetic agents (sulfonylureas) are potent sensitizers and cause these photosensitivity reactions.
Our job as pharmacists is to counsel patients on how to manage these reactions. One of the main counseling is emphasis on prevention by minimizing their exposure to light. However, if they are going to be exposed to sunlight, they have to make sure to apply sunscreen to prevent damage to their skin. Another way to manage this is by taking their medications at night if applicable, which would then have reduced concentration of the drug during the day time. When patients are being exposed to the sun, we can inform them about how the sun is strongest between 10am to 2pm. When patients are being exposed to the sun, it's important to choose a sunscreen with an SPF of 15 or higher and ensuring it covers both UVa and UVb rays. Patients should also make sure they are buying plain sunscreen and not the combination of bug repellent since sunscreen is applied more often. Sunscreen should also be applied 15-30 min before sun exposure and then every 2 hours when they are exposed to the sun.
In case these photosensitivity reactions occur, patients can use cool compresses, topical/systemic corticosteroid, or topical analgesics for symptom control such as inflammation, and itching. Depending on the severity, it can take a few weeks to months for the reaction to disappear. If the reaction does get worse, the offending agent must be stopped and the patient should be referred to their doctor for further evaluation.
I made a chart to distinguish the differences between the two types of photo sensitivities (attached below):
Reference:
JH; E. Phototoxicity and Photoallergy. Seminars in cutaneous medicine and surgery. https://pubmed.ncbi.nlm.nih.gov/10604793/. Accessed May 25, 2020.
Photosensitivity
Photosensitivity is a heightened skin sensitivity or an unusual reaction when your skin is exposed to UV radiation from sunlight. Photosensitivity can occur as a result of medications, a medical condition, a genetic disorder, or even from using certain types of skin care products. Photosensitivity is caused by an abnormal reaction to a component of the electromagnetic spectrum of sunlight and a chromophore within the skin. The most common photosensitivity is to UVA light, but patients can also be sensitive to UVB, ultraviolet radiation, visible light, or wider ranges of radiation. There are two distinct types of photosensitive reactions: photoallergic and phototoxic.
Phototoxicity is a common reaction and usually occurs when a medication is activated by exposure to UV light and causes damage to the skin that can look and feel lie a sunburn or a rash. This can also be triggered by certain ingredients in skin care products. A phototoxic reaction can happen within minutes or after hours of exposure and is usually limited to the skin that has been exposed. Photoallergic reactions on the other hand are a response far less common and occur when UV rays interact with the ingredients in medications or other products applied directly to the skin. This reaction type is classified as type IV hypersensitivity reactions. The body’s immune system recognizes changes caused by sun exposure as a foreign threat. The body produces antibodies and attacks, causing a reaction. A photoallergic reaction can leave you with a rash, blisters, red bumps or even oozing lesions one to three days after application and exposure to the sun.
Photosensitization of the skin can be caused by creams or ointments applied to the skin, medication taken orally or by injection, or by the use of prescription inhalers. In addition to an exaggerated skin burn, itching, scaling, rash, or swelling, exposure to UV light in combination with certain medication may result in skin cancer, premature skin aging, skin and eye burns, allergic reactions, reduced immunity, and blood vessel damage. There are many drugs that can cause photosensitivity. The primary classes of medications that are responsible for photosensitizing reactions include: antihistamines such as diphenhydramine and doxylamine, coal tar and derivatives, contraceptives containing estrogens, NSAIDs such as naproxen and ibuprofen, phenothiazines including perphenazine and promethazine, sulfonamides such as sulfadiazine and acetazolamide, sulfonylureas such as glipizide, thiazide diuretics such as hydrochlorothiazide, tetracyclines such as doxycycline, and tricyclic antidepressants including amitriptyline and imipramine.
Management of photosensitivity involved sun protection and treatment of the underlying disorder. Mainly, photosensitivity reactions are prevented by careful protection from sun exposure and avoidance of exposure to artificial sources of ultraviolet radiation. Protection involves avoiding exposure to direct sunlight, staying indoors, and seeking shade when outdoors, wearing broad spectrum SPF 50 or higher, covering all exposed skin. Sunscreen should protect from UVB and UVA and be water resistant and be generously applied every two hours while outdoors. The mainstay treatment however is wither the withdrawal of the drug, in photoallergic reactions, or reducing the dose of the medication, in phototoxic reactions.
References
Medications and other Agents that Increase Sensitivity to Light. (2015, December 21). Wisconsin Department of Health Services. https://www.dhs.wisconsin.gov/radiation/medications.htm
Oakley AM, Badri T, Harris BW. Photosensitivity. [Updated 2023 May 2]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK431072/
The Skin Cancer Foundation. (2022, January 28). Photosensitivity - The Skin Cancer Foundation. https://www.skincancer.org/risk-factors/photosensitivity/
Photosensitivity
Drug induced photosensitivity is an adverse effect of growing interest. Drug culprits belong to many different classes. Photosensitivity consists of phototoxic or photoallergic reactions in exposure to UV light or visible light. Drugs can increase one's sensitivity to the sun causing increased skin damage. These reactions occur in the UVA range wavelength 315-400 nm and sometimes in the UVB range 315-400 nm or visible light 400-740 nm.
Phototoxic reactions are more common than photoallergic reactions. These reactions are dependent on the dose of the medication and the exposure to light. These reactions usually consist of erythema that can be immediate, delayed or late-onset which is a reaction occurring more than a day after exposure. Immediate reactions are burning of the skin with a prickling sensation or edema (Hoffmann, G. A., & Weber, B.). Long term side effects from photoallergic reactions can be hyperpigmentation of the skin and telangiectasia. These reactions always occur in skin that absorbs UV radiation or visible light. A valence electron shifts to the outer shell, putting the molecule in an excited unstable state. Reactive oxygen species (ROS) are formed which causes oxidation of cellular lipids. Free radicals are also formed and can cause direct cell damage. Drugs that cause phototoxicity have a low molecular weight and planar, tricyclic or polycyclic configurations (Hoffmann, G. A., & Weber, B.). Phototoxicity subtypes include hyperpigmentation and dyschromia, pseudoporphyria, photo onycholysis, eruptive telangiectasia, and pellagra-like reaction (Di Bartolomeo, L. et al.).
Photoallergic reactions occur when the drug absorbs photons and becomes reactive. The drug acts as a hapten in the skin causing a reaction. Langerhans cells present the antigen to T cells via MHC II. This causes a cell mediated type IV reaction. These reactions have a low threshold dose for reaction. These reactions are rare and present as an eczematous rash on the skin. The reaction increases as time goes on and peaks at 48-72 hours. In contrast, phototoxic reactions have maximum clinical manifestations that peak at 24-48 hours of UV exposure. Photoallergic reactions are mainly induced by topical agents rather than systemic agents. Photoallergic subtypes include lichenoid reaction, photodistributed erythema multiforme, and subacute or chronic cutaneous lupus erythematosus (Di Bartolomeo, L. et al.).
Common classes of drugs causing photosensitivity include non-steroidal anti-inflammatory drugs (NSAIDs), antimicrobials, antihypertensives, and antineoplastic agents. Diagnosing phototoxic and photoallergic is important for treatment and prevention. First line treatment always consists of avoiding the offending drug. In many cases, the drug cannot be avoided. Reducing the dose of the drug or reducing time in the sun is the best way to treat these cases. Using sunscreen and clothes that provide shade like hats are also useful to supplement in protecting from UV radiation. Topical steroids can be used for phototoxicity. Topical steroids, antihistamines, and NSAIDs can be used for photoallergic reactions.
A growing area of research is the connection between photosensitizing drugs and photocarcinogenic effects. People that use photosensitizing drugs are at increased risk of developing skin cancer, but it may be due to many reasons. Patients may experience sunburn and not associate it with their medication. It is important that patients are aware of this side effect as it is difficult to avoid the sun and they can easily develop this adverse event.
Resources:
Di Bartolomeo, L., Irrera, N., Campo, G. M., Borgia, F., Motolese, A., Vaccaro, F., Squadrito, F., Altavilla, D., Condorelli, A. G., Motolese, A., & Vaccaro, M. (2022). Drug-Induced Photosensitivity: Clinical Types of Phototoxicity and Photoallergy and Pathogenetic Mechanisms. Frontiers in allergy, 3, 876695. https://doi.org/10.3389/falgy.2022.876695
Hofmann, G. A., & Weber, B. (2021). Drug-induced photosensitivity: culprit drugs, potential mechanisms and clinical consequences. Journal der Deutschen Dermatologischen Gesellschaft = Journal of the German Society of Dermatology : JDDG, 19(1), 19–29. https://doi.org/10.1111/ddg.14314
Photosensitivity
Photosensitivity is heightened skin sensitivity upon exposure to the sun’s ultraviolet radiation and can be a result of prescription or over-the-counter medication use, a medical condition or genetic disorder, or the use of certain skin care products. Photosensitive reactions are categorized into two types: phototoxicity and photoallergy. A phototoxic reaction occurs upon activation of the oral or topical administration of a drug with UV light exposure, resulting in damaged skin that feels sunburnt or has a rashy appearance. Likewise, this can also be caused by certain chemical constituents found in skincare products. Phototoxicity is the most common type of photosensitive reaction and is dose-related, occurring within minutes or hours of exposure. Generally, the affected area is only associated with sun-exposed parts of the skin. On the other hand, photoallergy is immune-related when the body’s immune system reacts through rashes, blisters, red bumps, or oozing lesions upon several days of UV exposure with ingredients in oral medications or other products applied directly to the skin. A photoallergic response, unlike a phototoxic response, is uncommon, not dose related, and has drug cross-sensitivity. Recognizing the difference between phototoxicity and photoallergy is crucial in determining the most optimal, therapeutic approach to provide symptomatic relief and avoid future complications.
Photosensitivity is caused by a variety of medications, diseases, and skincare products. More specifically, photosensitizing medications act as exogenous chromophores that absorb photons from solar radiation. The absorbed photons cause conformational, structural, or chemical changes in these compounds thereby leading to increased reactivity. Absorbed photons can generate reactive oxidative species (ROS), react directly with DNA, or produce local oxidative stress.
Common photosensitive medications include:
-Antidepressants: tricyclics -NSAIDs
-CV: HCTZ, β-blockers, amiodarone -Oral contraceptives
-Hypoglycemics: sulfonylureas -Sunscreens (PABA)
-Antipsychotics: phenothiazines -Antibiotics: tetracyclines, FQ, sulfonamides
Mechanism of Phototoxicity:
A phototoxic reaction ensues when the exogenous drug molecule absorbs UV radiation or visible light. The molecule, also known as exogenous photosensitizer, then switches from its singlet ground state to a singlet excited state and releases the absorbed energy in several ways: conversion to heat or fluorescence, or energy transfer to other adjacent molecules, for example, oxygen. Transferring energy to oxygen generates reactive oxygen species that cause cellular oxidative damage to lipids or proteins, which explains for the visible skin reactions. Photosensitizers can also covalently bind to DNA and cellular compartments that lead to photooxidation of cells and generate a visible phototoxic skin reaction. Histologic features of phototoxicity include cell necrosis and neutrophilic and lymphocytic infiltration of derma.
Mechanism of Photoallergy:
A photoallergic reaction is a T-cell mediated type IV reaction. Photosensitizing drugs absorb photons upon UV exposure and haptenization occurs. The energized exogenous chromophore binds to protein in the epidermis/dermis, which results in complete antigen formation, known as haptenization. Langerhan cells process the antigen and MHC II complex presents the antigen to naive T cells in the lymph nodes that leads to differentiation of photoallergy-specific T cells. Upon re-exposure to the offending photosensitizing agent, a photoallergic reaction occurs through the release of cytokines, chemokines, and recruitment of inflammatory cells. Histologic features of photoallergy include epidermal spongiosis, vesiculation, exocytosis of lymphocytes into the epidermis, and perivascular inflammatory infiltrates.
To treat a photosensitive reaction, administration of antihistamine and/or corticosteroids is the standard treatment. One of the highly effective therapeutic approaches for photoallergy include prednisone 1 mg/kg/day for 3-10 days or tapered over 3 weeks. Topical corticosteroids include betamethasone valerate 0.1% cream. If the individual is experiencing pain or inflammation, administer NSAIDs, i.e. indomethacin 25 mg TID. As for non-pharmacological therapy, apply a cold compress if appropriate. In a photoallergic response, discontinue the offending agent and do not readminister the photosensitizing agent in the future, and avoid other medications that have similar chemical constituents as the offending agent due to the risk of cross-reactivity. In a phototoxic response, systemic or topical corticosteroids, analgesics, and antihistamines are also used depending on severity. Unlike a photoallergic response, drugs causing phototoxicity may or may not be discontinued based on patient and provider decision. Precautionary measures should be taken in drugs known to cause phototoxicity, such as avoiding sun exposure (if possible), applying broad spectrum sunscreen daily, or wearing long-sleeved clothing, hats, and sunglasses when outside.
References
Kurz, Berandett. “Turn the Light on Photosensitivity.” Journal of Photochemistry and Photobiology, 22 Sept. 2021, www.sciencedirect.com/science/article/pii/S2666469021000567#sec0002.
Lozzi, Flavia, et al. “Latest Evidence Regarding the Effects of Photosensitive Drugs on the Skin: Pathogenetic Mechanisms and Clinical Manifestations.” Pharmaceutics, 17 Nov. 2020, www.ncbi.nlm.nih.gov/pmc/articles/PMC7698592/.
“Photosensitivity.” The Skin Cancer Foundation, 28 Jan. 2022, www.skincancer.org/risk-factors/photosensitivity/.
Written by Justin Ayob and Antonio Ortega
Photosensitivity can put you at risk for skin damage and skin cancer when exposed to ultraviolet radiation. The more one can learn about photosensitivity, the more one can take precautions to protect their skin. Some individuals may not develop a sensitivity to the sun but if you do, there are steps to prevent photosensitivity from occurring.
Photosensitivity can be caused by UV radiation from tanning a period, OTC medications, genetic disorders, and some selective skincare products. Two types of photosensitivity reactions occur, photoallergic and phytotoxic. photo-toxic is the more common of the two, it occurs when the medication one is taking is activated by UV light and causes a reaction that causes damage to the skin. It usually occurs within minutes or hours after taking the medication and usually occurs in the area where the medication was applied to. Photo allergic is less common and happens when UV rays interact with the ingredients in medicines or other products applied directly to the skin. The body’s immune system recognizes changes caused by sun exposure as a foreign threat. The body produces antibodies and attacks, causing a reaction. A photo-allergic reaction can leave you with a rash, blisters, red bumps, or even oozing lesions one to three days after application and exposure to the sun.
Some helpful ways of avoiding photosensitivity reactions are to ask your doctor or dermatologist about any medications that may have a photosensitivity side effect and to let them know if you have any medical conditions. It is also important to always read warning labels on medication bottles.
If a reaction does occur, you would treat it like a sunburn. You may contact your doctor if you develop a fever with chills, nausea, headache, and weakness, or if your skin blisters. There are also diagnostic tests, such as photo-testing, and photo-patch testing to see if the photosensitive reaction was secondary to a photosensitive reaction.
Always take safety measures, and try to minimize your skin's exposure to the sun (10 AM – 4 PM). Wear protective clothing such as a hat and long sleeves if possible and use sunscreen with an SPF of at least 30.
References:
Photosensitivity. The Skin Cancer Foundation. https://www.skincancer.org/risk-factors/photosensitivity/. Published January 28, 2022. Accessed April 25, 2022.
Donna Salib & Natalie Eshaghian
Photosensitivity
Photosensitivity is when your skin reacts poorly to the sun/UV light. Photosensitivity can feel a lot like a sunburn, but can also become a rash which is why it is important for patients on certain medications to take precautions and wear protective clothing such as hats, long sleeve shirts, and apply a broad-spectrum sunblock. There are two types of photosensitivity called phototoxic and photoallergic. (1) Phototoxic agents are agents that cause things like sunburn and are typically still continued in patients when the reaction occurs. However, photoallergic agents cause effects such as lesions and are agents that should be avoided since the patient has an allergen to the agent. Toxic photosensitivity is a chemically induced skin irritation that requires light and involves a chemical that affects the skin by topical administration or systemic circulation. The chemical is usually photoactive meaning that when it absorbs light, it produces molecular changes that cause toxicity and results in erythema and blistering 5-15 hours after exposure. Phototoxicity affects the sun-exposed skin only while photoallergy can affect and distribute to the unexposed areas. Photoallergy is not dose-dependent but occurs when a drug or its metabolite induces a cell-mediated immune response due to exposure of longer wavelengths from the sun and is time-dependent thus it can produce a delayed reaction of papular or eczematous contact dermatitis. Photopatch testing is an important diagnostic tool to assess photoallergic reactions.
These abnormal photosensitivity reactions can occur either locally or systemically. Most phototoxic reactions result from systemic administration of medications while photoallergic reactions can be caused by either topical or systemic administration of a drug. Products such as sunscreens that contain PABA or Para-aminobenzoic acid and benzophenone, and topical NSAIDs, can cause such a reaction. NSAIDs, sulfonylureas, and thiazide diuretics are known drugs to cause photoallergic reactions systemically. Drugs such as tetracycline, fluoroquinolones, chlorpromazine, and amiodarone are also known to cause phototoxic effects. Amiodarone is a cardiovascular medication used to treat ventricular arrhythmias and atrial fibrillation. The medication is found to be photosensitive, causing phototoxicity. (2) The method of treatment for agents that are phototoxic is to initially lower the dose of the amiodarone to an effective dose that will also get rid of the photosensitivity reactions. However, if that is ineffective the patient can use systemic corticosteroids or topical antihistamines.(3) Other agents are found to be photoallergic in patients. In this case, the patient should immediately start an antihistamine and a corticosteroid, such as prednisone at 1mg/kg/day for 3-10 days or topical corticosteroid such as betamethasone valerate 0.1% cream. If that is ineffective then the agent is stopped completely and not restarted. It is important to understand that patients who have photoallergic reactions should note that there are other medications with the same components that the patient can be allergic to, such as if a patient is photoallergic to sulfonamide medications they avoid all sulfonamide and sulfur-containing medications.
It is especially important for cancer patients to apply sunscreen and continue to reapply as there are many patients that get severe sunburns even in the darkest of winters triggered by their photosensitivity when on anti-cancer therapy, such as bleomycin. In 2011, the FDA passed a rule that sunscreen can only be labeled as broad-spectrum if it offers UVA protection that is proportional to UVB protection. (4) For cancer patients that are susceptible to photosensitivity, chemical sunscreens may not be the best option as those products can cause a burning sensation on broken skin. Physical sun blockers such as zinc oxide or titanium dioxide reflect or scatter UV radiation and cause less irritation to broken skin.
Overall, it is important to understand the difference between phototoxic and photoallergic signs and symptoms and how to treat the two. In addition, if someone is taking a medication known to cause photosensitivity, such as tretinoin and other medications, they should take the proper precautions to protect their skin from the harmful reactions that can occur. Lastly, photosensitivity is a serious side effect that should be considered when taking certain medications, and if one knows that they will be exposed to sunlight and photons then they should either switch to a medication that is not photosensitive or protect themselves from experiencing its effects when doing so.
References:
Epstein JH. Phototoxicity and photoallergy. Semin Cutan Med Surg. 1999;18(4):274-284. doi:10.1016/s1085-5629(99)80026-1
Walter JF, Bradner H, Curtis GP. Amiodarone photosensitivity. Arch Dermatol. 1984;120(12):1591-1594.
Blakely KM, Drucker AM, Rosen CF. Drug-Induced Photosensitivity-An Update: Culprit Drugs, Prevention and Management. Drug Saf. 2019;42(7):827-847. doi:10.1007/s40264-019-00806-5
Center for Drug Evaluation and Research. Sunscreen: How to help protect your skin from the sun. U.S. Food and Drug Administration. Available at: https://www.fda.gov/drugs/understanding-over-counter-medicines/sunscreen-how-help-protect-your-skin-sun#:~:text=As%20of%20June%202011%2C%20sunscreens,both%20UVA%20and%20UVB%20radiation Date Accessed August 11, 2021.
Redness. Itching. Hives. The first thought that comes to my mind when I hear of these symptoms is allergies. Allergies are associated with rash and hives so when a person experiences an allergic reaction, they experience these symptoms. Photosensitivity is known as sun allergy. A person’s skin can be sensitive to the ultraviolet (UV) radiations from the sun or tanning beds leading them to experience such symptoms. Photosensitivity can be induced through certain medications, diseases and medical conditions as well as certain skin care products. Common areas of the skin that can be exposed to UV rays are the face, ears, neck, back of the hands, arms, and at times on the feet and lower parts of the legs.
There are two different types of photosensitive reactions: phototoxic and photoallergy. Phototoxic is the more common photosensitive reaction that occurs. This reaction can occur from certain medications whether it is oral or topical formulation as well as certain ingredients in the skin care products. These certain medications and ingredients can become activated by the UV rays of the sun or tanning beds. This means that if you take these medications or apply certain products and then decide to go for a walk with shorts and a tank top, then your skin might have a reaction by being out in the sun. It can feel like a sunburn and your skin can become blistered, feel itchy, etc. A phototoxic reaction can occur right away but at times it can also occur hours after the exposure to the UV rays have occurred. In phototoxic reactions, it is limited to the area of the skin that has been exposed.
Photoallergic is a less common photosensitive reaction that occurs and it occurs when UV rays interact with ingredients of medications or skin products that are directly applied on the skin. Common topical formulations can be such as creams, lotions, and gels. A photoallergic reaction is similar to when a person has a cold. It starts off with the body noticing that there are foreign substances and then the body’s fighter cells try to fight those substances off so that the body can go back to being normal and healthy. In the process of fighting off a cold, you notice symptoms such as a cough, mucus production, fatigue and more. Similarly, when a person experiences a photoallergic reaction the body’s fighter cells notice that the UV rays are harming the skin so the body tries to fight them off resulting into a person experiencing symptoms such as blisters, rash, and at times oozing lesions. This can occur from one up to three days after the topical application and exposure to the UV rays. The Skin Cancer Foundation has provided a detailed list of medications that can cause photosensitivity as a side effect as well as list of diseases that can cause photosensitivity. Certain skin care products such as retinols, benzoyl peroxide, vitamin C and more may also cause photosensitivity which is why it is crucial to apply sunscreen especially when using these products.
It is important to minimize exposure to UV rays to help protect against the harmful effects that can be caused by them. Wearing a brimmed hat as well as sun-protective clothing such as long sleeves and tight clothes can help protect the skin. It is also crucial to apply sunscreen SPF 30 or higher at least 30 minutes prior to UV ray exposure. Apply on all areas that will be exposed and make sure to reapply sunscreen every 2 hours. Lastly, make sure to visit a dermatologist and follow-up to ensure that the skin is healthy.
“Photosensitivity.” The Skin Cancer Foundation, 27 May 2021, www.skincancer.org/risk-factors/photosensitivity/.
“Photosensitivity Report - Medications.” The Skin Cancer Foundation, 26 Jan. 2021, www.skincancer.org/risk-factors/photosensitivity/medications/.
“Diseases Related to Abnormal Photosensitivity Responses of the Skin.” The Skin Cancer Foundation, 19 June 2020, www.skincancer.org/risk-factors/photosensitivity/diseases/#1565202675317-18826a83-e996.
Photosensitivity occurs when the skin’s reactivity to light and the sun is increased. Various medications have this as a warning or precaution when taking it. Lots of antibiotics, for example, will include a sticker telling patients to stay out of the sun and wear sunscreen while taking the medication. Photosensitivity can either be photoallergy or phototoxicity. Photoallergy is rare, and occurs when exposure to UV light turns the drug into a hapten and causes it to act as an allergen, causing an immune response. This response can look like hives, erythema and dermatitis, and can spread to other parts of the body that weren’t exposed to the light. This reaction usually does not occur immediately after exposure, and often has a latency period of 23-72 hours. This reaction is not dependent on the dose of the medication itself.
This is in contrast to phototoxicity, which typically occurs quickly after exposure to UV light and is dose dependent. This reaction is much more common and presents more as severe sunburn, with skin peeling, pain and a feeling of skin burning. In this scenario, the medication absorbs the UV light and acts as a toxin, causing damage, but only on the parts of the skin that was exposed. Most phototoxic drugs are activated by UVA light rather than UVB, similar to photoallergic drugs as well.
Besides antibiotics, some other medications that can cause this reaction include NSAIDs, diuretics, anticonvulsants, anti-diabetic agents, and cardiovascular agents. When patients are on these medications, a huge emphasis should be placed on preventing a photosensitivity reaction. If appropriate for the medication, they can be taken at night instead, during a time where sunlight exposure would be minimal and lower concentrations of drug would be present in the body during daylight. As pharmacists we can also let our patients know that the sun is usually strongest between 10 am to 4 pm, and that cloud cover does not mean no risk of sun exposure. They can pick up a sunscreen that is SPF 15 or 30 that is broad spectrum and water resistant.
If a photosensitivity reaction does occur, treatment would be based on severity and might include cold compresses, topical/systemic corticosteroids, or topical analgesics. For both phototoxic and photoallergic reactions, the offending drug or chemical causing exogenous photosensitivity should be discontinued whenever possible. Topical anesthetics should be avoided because of the possibility of a contact allergy. For more severe reactions, systemic corticosteroids may need to be continued for 2 to 3 weeks.
1. Craig A Elmets, MD. Photosensitivity disorders (photodermatoses): Clinical manifestations, diagnosis, and treatment. UpToDate. Nov 2019.
Photosensitivity is a reaction that occurs on the skin when it is exposed to light. It can be further classified as a photoallergic or a phototoxic reaction. Photo allergic reactions are a rare immunological response that is not dose-related and usually occurs after repeated exposure to a drug. Light causes the drug to act as a hapten in the body, this triggers a hypersensitivity immune response within the body and leads to a skin reaction. This skin reaction can be anywhere on the body and is a delayed reaction so can take from 24-72 hours to appear on the skin.
Phototoxic reactions happen when a drug absorbs UVA light and causes cellular damage. The reaction is usually dose dependent but does not demonstrate cross-sensitivity. A skin reaction occurs only on the areas exposed to sunlight and can appear as a severe sunburn. The skin reaction leads to peeling of the skin, pain, and a burning sensation.
There is a multitude of drugs that can have a side effect of causing photosensitivity. Big medication classes including antibiotics (fluoroquinolones, tetracyclines, and other antibiotics including nitrofurantoin, and sulfamethoxazole), NSAIDs (naproxen, ketoprofen, and piroxicam), diuretics (furosemide and hydrochlorothiazide), anti-diabetic agents (glipizide, glyburide, and tolbutamide), and anticonvulsants (carbamazepine and lamotrigine) are known to cause photosensitivity. The best way to manage drug-induced photosensitivity is to prevent the reaction from happening. Although photoallergic reactions cannot be prevented, precautions can be taken to precent phototoxic reactions from occurring. Patients taking medications need to be counseled by the pharmacist to optimally decrease the chance of this reaction. Limitation of sun exposure and well as wearing sunscreen daily is a great counseling point when talking to patients picking up these medications at the pharmacy. If possible, it is also encouraged to take these medications at night. This allows most of the medication to be metabolized and excreted by the body before the sun peaks between the hours of 10 am and 2 pm. Choosing a broad spectrum sunscreen with SPF 15 or higher is strongly encourages any time of year but it is especially encouraged when patients are on medications with a high incidence of photosensitivity.
If the photosensitive reaction occurs the medication should be discontinued. If a photoallergic reaction is occurring, the patient should not try to reintroduce this medication once the rash has resolved. If a phototoxic reaction is occurring, the patient may reintroduce the medication once the reaction has resolved as long as they take extra precautions to avoid sun exposure.
Applying a cool compress, applying a topical or taking a systemic corticosteroid, or applying topical analgesics to decrease some of the discomfort from the rash. In some cases, it may take weeks or months for the entirety of the reaction to resolve.
References:
Clinical Resource, Drug-Induced Photosensitivity. Pharmacist’s Letter/Prescriber’s
Letter. August 2019.
Crosby K. and O’Neal K., (2017), "Chapter 39: Prevention of Sun-Induced
Skin Disorders," Handbook of Nonprescription Drugs: An Interactive Approach to Self-Care, 19th Edition
Zhang, A. (2020, September 18). Drug-Induced Photosensitivity. Retrieved January 8, 2021.
Photosensitivity occurs when there is increased sensitivity of light on the skin that results in an abnormal red and painful change on the skin’s surface. Photosensitivity can also occur to the patient’s eyes and cause redness in the area. The types of photosensitivity include photo allergy and phototoxicity. Phototoxicity is more common than photo allergy and is a nonimmunological reaction that presents with erythema or redness that looks like a sunburn on a patient’s body. On the other hand, photo allergy presents as urticaria and is an immunological reaction that causes antigens to form in the body causing a delayed type hypersensitivity reaction. Both of these can occur due to side effects from different medications and drug classes. Photoallergic reactions generally occur 24-72 hours after the patient is exposed to the light while phototoxic reactions are likely to occur within minutes to hours after light exposure. Medications that can cause this phenomenon include many different antibiotics like doxycycline, sulfamethoxazole with trimethoprim (Bactrim) and ciprofloxacin. Non-steroidal anti-inflammatory drugs (NSAIDs) like naproxen and ibuprofen, diuretics like furosemide, cardiovascular regulating agents like amiodarone and sulfonylureas for diabetes all are medications that can result in photosensitive reactions. Pharmacists can contribute to the managing of side effects due to their comprehensive knowledge of medications. They as health care professionals can help aid patients prevent photosensitivity reactions by counseling patients to have little to no contact with sun light, especially at peak sun hours between 10am and 2pm when this side effect is a fairly common occurrence. If a patient is to have sunlight contact, he or she should be applying sunscreen 15 to 30 minutes prior to sun exposure with SPF that is at least SPF 15 that is also broad spectrum sunscreen covering both UVA and UVB light rays. Reapplication of sunscreen should also be stressed every 2 hours the patient is exposed to sunlight after the initial application. Another important counseling point is that if the photosensitivity is due to medications, a pharmacist can suggest taking these medications at night so that in the day the drug is less concentrated in the patient’s body. Aside from these prevention techniques, if a patient starts to actually experience the photosensitivity reaction there are ways to manage it. Pharmacists can counsel patients to use cool compresses, use topical or systemic steroidal agents to control inflammation and itching such as over the counter hydrocortisone cream or recommend systemic steroids or a stronger topical cream to the patient’s physician to prescribe. The patient should also use topical or systemic analgesics if they are experiencing any pain. Many patients do not experience a photosensitive reaction the first time they take the causing medication because there is a latency period of developing this side effect. The reaction also is not dose dependent and depends more on how long the patient is taking the medication. Should this reaction occur, it is recommended to discontinue the medication altogether since it is not dose dependent and the patient should be started on a medication of a different class to avoid said reaction again. In some cases of severe reactions resulting in heavy skin burning and peeling, it can take as long as a few weeks to months for the reaction to fully go away. Therefore, counseling the patient is key in order to prevent these dangerous reactions from occurring in the first place.
Reference:
Dubakiene R, Kupriene M. Scientific problems of photosensitivity. Medicina (Kaunas). 2006;42(8):619-24. PMID: 16963827.
Photosensitivity disorders refer to the dermatological response after exposure to ultraviolet (UV) radiation or phototoxic agents. There are two main reactions: phototoxicity and photoallergy.
Phototoxicity occurs more frequently with a quicker onset from minutes to hours after exposure to the offending agent, and is more likely to be drug-induced. It occurs when the offending agent exceeds the threshold concentration and generally requires large amounts in order to cause a reaction. Phototoxicity reactions typically present as exaggerated sunburns. Likely culprits include: tetracyclines (especially doxycycline), hydrochlorothiazide, sulfonamides, metformin, fluoroquinolones, NSAIDs (especially ketoprofen), phenothiazines, amiodarone, retinoids, St. John’s wort.
Photoallergy is a delayed-type immunological reaction caused by repeated exposure to small amounts of an offending allergen. After the first encounter, the allergen changes its antigenicity in response to UV radiation, and upon a repeat exposure, will initiate an allergic reaction. Photoallergic reactions typically present with pruritis, eczematous eruptions in sun-exposed areas of skin that develop 24-48 hours after exposure. Likely culprits include: sunscreens, topical NSAIDs (especially diclofenac), fragrances, phenothiazines, antimicrobial agents, quinolones, sulfonamides, systemic NSAIDs (especially ketoprofen).
In both cases, treatment mainly consists of identifying and discontinuing the offending agent, as well as providing supportive care. In severe cases, symptomatic relief with topical or systemic corticosteroids and/or topical analgesics may be considered. Prevention is also stressed, as these reactions may persist for weeks to months, even after the discontinuation or tapering of the offending agent. Sunscreens with sun protection factor (SPF) 15 or greater are recommended for daily use prior to any sun exposure, as well as sun avoidance and sun-protective clothing.
References
Blakely KM, Drucker AM, Rosen CF. Drug-Induced Photosensitivity—An Update: Culprit Drugs, Prevention and Management. Drug Safety. 2019;42(7):827-847. doi:10.1007/s40264-019-00806-5.
Marneros AG, Bickers DR. Photosensitivity and Other Reactions to Light. In: Jameson J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J. eds. Harrison's Principles of Internal Medicine, 20e New York, NY: McGraw-Hill
Written by: Denise Cotter and Niyati Doshi
Photosensitivity can be separated into two categories: photoallergy and phototoxicity. Both are caused by the skin’s increased reactivity to light. Common medications that are photosensitizers include antibiotics (ciprofloxacin, doxycycline, tetracycline), NSAIDs, diuretics (furosemide, HCTZ), anticonvulsants (carbamazepine, lamotrigine), antidepressants (amitriptyline), and cardiovascular agents (amiodarone, nifedipine) just to name a few. Photoallergy is a rare reaction and it produces an immunologic response resulting in urticaria, erythema, and dermatitis. It usually occurs 24-72 hours after light exposure and can spread to other areas that were not exposed to light. Phototoxicity is more common and it mimics a severe sunburn, with skin peeling, pain, and a burning sensation. Unlike a photoallergy, it is only present on the skin that is directly exposed to light and occurs within minutes to hours of post light exposure. Prevention is key and when patients are at risk for photosensitivity they should minimize their exposure to sunlight. This can be done by wearing protective clothing, using a broad spectrum sunblock with an SPF of 15 or higher, and staying inside or in the shade when sun ray’s are the strongest, between 10 am and 2 pm. It may take weeks or months for a reaction to disappear but it can be treated by symptom management: cool compresses, topical or systemic corticosteroids, and topical analgesics. If a medication is the cause of this reaction and persists or gets worse the drug may be stopped or switched to a less photosensitizing agent or the dose may be reduced.
Photodynamic therapy (PDT) is a two-step treatment where a drug that acts as a photosensitizer is administered to specifically target a diseased tissue, followed by illumination with visible light to activate the drug and destroy the target tissue. It was developed for the treatment of cancer and precancers. The visible light that can be used for PDT varies: coherent light sources (lasers and light-emitting diodes, incoherent sources (broadband lamps), and natural sunlight. However, only validated light sources can be recommended, and two are FDA approved: BLU-U Blue Light Photodynamic Therapy Illuminator 400 nm and (red) BF-RhodoLED 635 nm. PDT has been used to treat actinic keratosis, basal cell carcinoma, and squamous cell carcinoma in situ (Bowen disease). Approval for treatment varies from country to country. Like any treatment it is important to implement safety measures. Retinal damage from the visible light has been seen and it may cause age-related macular degeneration, therefore appropriate goggles that block either blue or red light should be worn during the illumination process. Use of other photosensitizing agents should be used with caution and it may be recommended that certain medications be stopped one to two weeks prior to PDT if possible, such as tetracycline. PDT is known to improve the appearance of hypertrophic scars. After treatment patients are told to stay inside during daylight and to avoid bright indoor light for 48 hours after treatment. If the skin is irritated or pruritic, a topical corticosteroid can be used and cold compresses can be applied for comfort.
Reference(s):
Allison RR, Moghissi K. Photodynamic Therapy (PDT): PDT Mechanisms. Clin Endosc. 2013;46(1):24-9. doi: 10.5946/ce.2013.46.1.24
https://www-uptodate-com.jerome.stjohns.edu/contents/photodynamic-therapy?search=photodynamic%20therapy&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1#references
Photosensitivity Power Point - Click Below
Nice chart, thank you Dirshti...
Many common drugs like antibiotics, NSAIDs, and anti-diabetic medications can cause photosensitivity, which is an adverse reaction that gets overlooked in many cases. Some specific medications that can cause a photosensitive reaction include amiodarone, nifedipine, furosemide, naproxen, amitriptyline, hydrochlorothiazide, ciprofloxacin, doxycycline, tetracycline, carbamazepine and sulfamethoxazole. It is important to note that there is a difference between photosensitivity, photoallergy and phototoxicity. Photosensitivity is when the skin has an increased reaction to sunlight. This can be further broken down into two categories: photoallergy and phototoxicity. Photoallergy presents as a rare reaction induced by the sun when a drug is the allergen. When ingested, the drug acts as a hapten and when bound to the antigen produces an allergic immunologic response. This reaction presents with urticaria, erythema, and dermatitis. This reaction exists 24 - 72 hours after exposure to UV light. Many patients don’t experience something the first time taking the drug due to a latency period. This reaction is also independent of the dose. Phototoxicity on the other hand is a little different where it occurs more often and does not spread. It presents as a severe sunburn with a painful and burning sensation. The skin will eventually begin to peel as with any sunburn. The onset of symptoms happens much more frequently with minutes to hours after sun exposure. And unlike a photoallergy, it is dose dependent. Degrees of treatment rely heavily on prevention. Patients should be advised to minimize their exposure to sunlight and take their medications at night. When presented with a painful phototoxic or photoallergic reaction, the treatment is symptom based and depends on severity. Some of the treatment options include cool compresses, topical or systemic corticosteroids, and topical analgesics. In some cases it may take as long as weeks to months for a reaction to subside. The offending drug can then be discontinued and switched to another agent; or the physician may choose to continue with the same medication at a lower dose.
Natanova, Marina “ Drug Induced Photosensitivity” APPE presentation 2017
Photosensitivity refers to the skin’s increased reactivity to light exposure. This can present as a side effect of drugs. The PowerPoint discusses two drug-induced photosensitivity disorders: phototoxicity and photoallergy. Some common photosensitizers include antibiotics (fluroquinolones, tetracyclines, bactrim), anticonvulsants (carbamazepine, lamotrigine), NSAIDs, diuretics (furosemide, hydrochlorothiazide), etc.
Phototoxicity is the more common of the two disorders. It is a nonimmunological reaction that usually presents with erythema resembling a sunburn, which usually peels within a few days. Photoallergy is a less common, immunological reaction. UV light exposure creates an unstable hapten, which can bind to macromolecules to form an antigen capable of causing a delayed-type hypersensitivity reaction. It can present with urticaria or as a pruritic eczematous dermatitis. It differs from a phototoxic reaction in that it is not dose-dependent and can spread to areas that were not exposed to the sun. Some patients may even develop a condition known as “persistent light reaction”, which is a hypersensitivity to light even after the offending agent is discontinued. Photoallergic reactions typically occur 24-72 hours post light exposure, while phototoxic reactions occur within minutes to hours post exposure.
The first step of managing a drug-induced photosensitivity reaction is identifying the offending agent and either discontinuing or lowering the dose based on severity. There’s also a strong emphasis put on prevention by minimizing sun exposure and applying broad-spectrum sunscreen. Sunscreens should be SPF 15 or higher, applied 15-30 minutes before going out, and reapplied at least every 2 hours while in the sun. Treatment focuses on symptom management with use of cool compresses, topical or systemic corticosteroids, and topical analgesics chosen based on severity. Some reactions may take weeks or months to resolve. For photoallergic patients with persistent light reaction, an immunosuppressive drug, such as azathioprine, may be necessary.
Reference:
Marneros AG, Bickers DR. Photosensitivity and Other Reactions to Light. In: Jameson J, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J. eds. Harrison's Principles of Internal Medicine, 20e New York, NY: McGraw-Hill.
Photosensitivity is when your skin’s sensitivity is increased when it comes in contact with light. There are different types of photo sensitivities: photoallergy and phototoxicity. A lot of times patients experience this due to the various different medications they are taking. Hence, it is very important for us as pharmacists to counsel patients on such medications to help prevent them from experiencing this. Medications that can cause these reactions are many different classes. A few more commonly used medications such as antibiotics (ciprofloxacin, doxycycline, tetracycline, bactrim), NSAIDs, Diuretics, CV agents (amiodarone, nifedipine), anti-diabetic agents (sulfonylureas) are potent sensitizers and cause these photosensitivity reactions.
Our job as pharmacists is to counsel patients on how to manage these reactions. One of the main counseling is emphasis on prevention by minimizing their exposure to light. However, if they are going to be exposed to sunlight, they have to make sure to apply sunscreen to prevent damage to their skin. Another way to manage this is by taking their medications at night if applicable, which would then have reduced concentration of the drug during the day time. When patients are being exposed to the sun, we can inform them about how the sun is strongest between 10am to 2pm. When patients are being exposed to the sun, it's important to choose a sunscreen with an SPF of 15 or higher and ensuring it covers both UVa and UVb rays. Patients should also make sure they are buying plain sunscreen and not the combination of bug repellent since sunscreen is applied more often. Sunscreen should also be applied 15-30 min before sun exposure and then every 2 hours when they are exposed to the sun.
In case these photosensitivity reactions occur, patients can use cool compresses, topical/systemic corticosteroid, or topical analgesics for symptom control such as inflammation, and itching. Depending on the severity, it can take a few weeks to months for the reaction to disappear. If the reaction does get worse, the offending agent must be stopped and the patient should be referred to their doctor for further evaluation.
I made a chart to distinguish the differences between the two types of photo sensitivities (attached below):
Reference:
JH; E. Phototoxicity and Photoallergy. Seminars in cutaneous medicine and surgery. https://pubmed.ncbi.nlm.nih.gov/10604793/. Accessed May 25, 2020.