Photosensitivity refers to an increased skin sensitivity or an unusual reaction when exposed to UV radiation from sunlight. It can result from medications, medical conditions, genetic disorders, or certain skincare products. This condition is triggered by an abnormal reaction to a component of sunlight's electromagnetic spectrum and a chromophore within the skin. The most common photosensitivity is to UVA light, but individuals can also be sensitive to UVB, ultraviolet radiation, visible light, or broader ranges of radiation. There are two distinct types of photosensitive reactions: photoallergic and phototoxic.
Phototoxicity is a common reaction that typically occurs when a medication is activated by exposure to UV light, causing skin damage that resembles a sunburn or rash. This can also be triggered by specific ingredients in skincare products. A phototoxic reaction can happen within minutes or hours of exposure and is usually limited to the exposed skin. In contrast, photoallergic reactions are far less common and occur when UV rays interact with ingredients in medications or other products applied directly to the skin. This reaction type is classified as a type IV hypersensitivity reaction, where the immune system recognizes changes caused by sun exposure as a foreign threat. The body produces antibodies and attacks, resulting in a reaction. A photoallergic reaction can manifest as a rash, blisters, red bumps, or oozing lesions one to three days after application and exposure to the sun.
Photosensitization can be caused by creams or ointments applied to the skin, oral or injectable medications, or prescription inhalers. In addition to exaggerated sunburn, symptoms may include itching, scaling, rash, or swelling. Exposure to UV light combined with certain medications may also result in skin cancer, premature skin aging, burns to the skin and eyes, allergic reactions, reduced immunity, and blood vessel damage. Many drugs can cause photosensitivity. Primary classes of medications responsible for photosensitizing reactions include antihistamines such as diphenhydramine and doxylamine, coal tar and its derivatives, contraceptives containing estrogens, NSAIDs like naproxen and ibuprofen, phenothiazines including perphenazine and promethazine, sulfonamides such as sulfadiazine and acetazolamide, sulfonylureas like glipizide, thiazide diuretics such as hydrochlorothiazide, tetracyclines like doxycycline, and tricyclic antidepressants including amitriptyline and imipramine.
Managing photosensitivity involves sun protection and addressing the underlying disorder. Primarily, photosensitivity reactions are prevented by avoiding sun exposure and artificial sources of ultraviolet radiation. Protective measures include staying out of direct sunlight, remaining indoors, seeking shade when outdoors, wearing broad-spectrum SPF 50 or higher sunscreen, and covering all exposed skin. Sunscreen should protect against both UVB and UVA rays, be water-resistant, and be generously applied every two hours while outdoors. The main treatment involves either withdrawing the drug, in the case of photoallergic reactions, or reducing the medication dose in phototoxic reactions.
Photosensitivity refers to an increased skin sensitivity or an unusual reaction when exposed to UV radiation from sunlight. It can result from medications, medical conditions, genetic disorders, or certain skincare products. This condition is triggered by an abnormal reaction to a component of sunlight's electromagnetic spectrum and a chromophore within the skin. The most common photosensitivity is to UVA light, but individuals can also be sensitive to UVB, ultraviolet radiation, visible light, or broader ranges of radiation. There are two distinct types of photosensitive reactions: photoallergic and phototoxic.
Phototoxicity is a common reaction that typically occurs when a medication is activated by exposure to UV light, causing skin damage that resembles a sunburn or rash. This can also be triggered by specific ingredients in skincare products. A phototoxic reaction can happen within minutes or hours of exposure and is usually limited to the exposed skin. In contrast, photoallergic reactions are far less common and occur when UV rays interact with ingredients in medications or other products applied directly to the skin. This reaction type is classified as a type IV hypersensitivity reaction, where the immune system recognizes changes caused by sun exposure as a foreign threat. The body produces antibodies and attacks, resulting in a reaction. A photoallergic reaction can manifest as a rash, blisters, red bumps, or oozing lesions one to three days after application and exposure to the sun.
Photosensitization can be caused by creams or ointments applied to the skin, oral or injectable medications, or prescription inhalers. In addition to exaggerated sunburn, symptoms may include itching, scaling, rash, or swelling. Exposure to UV light combined with certain medications may also result in skin cancer, premature skin aging, burns to the skin and eyes, allergic reactions, reduced immunity, and blood vessel damage. Many drugs can cause photosensitivity. Primary classes of medications responsible for photosensitizing reactions include antihistamines such as diphenhydramine and doxylamine, coal tar and its derivatives, contraceptives containing estrogens, NSAIDs like naproxen and ibuprofen, phenothiazines including perphenazine and promethazine, sulfonamides such as sulfadiazine and acetazolamide, sulfonylureas like glipizide, thiazide diuretics such as hydrochlorothiazide, tetracyclines like doxycycline, and tricyclic antidepressants including amitriptyline and imipramine.
Managing photosensitivity involves sun protection and addressing the underlying disorder. Primarily, photosensitivity reactions are prevented by avoiding sun exposure and artificial sources of ultraviolet radiation. Protective measures include staying out of direct sunlight, remaining indoors, seeking shade when outdoors, wearing broad-spectrum SPF 50 or higher sunscreen, and covering all exposed skin. Sunscreen should protect against both UVB and UVA rays, be water-resistant, and be generously applied every two hours while outdoors. The main treatment involves either withdrawing the drug, in the case of photoallergic reactions, or reducing the medication dose in phototoxic reactions.
Blakely KM, Drucker AM, Rosen CF. Drug-induced photosensitivity – an update: culprit drugs, prevention and management. Drug Saf. 2019 Jul;42(7):827-47. https://link-springer-com.jerome.stjohns.edu/article/10.1007/s40264-019-00806-5
George EA, Baranwal N, Kang JH, et al. Photosensitizing medications and skin cancer: a comprehensive review. Cancers (Basel). 2021 May;13(10):2344. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8152064/