Drugs May Trigger Sun Allergy Reactions

A sun allergy, also referred to as photosensitivity, occurs when the immune system reacts to sunlight, resulting in an itchy red rash. Areas of the skin exposed to the sun, such as the neck, hands, arms, and legs, may be affected. Polymorphous light eruption (PMLE) is the second most common skin condition related to the sun, after sunburn. Another type of sun allergy, photoallergic eruption, occurs when a chemical applied to the skin combined with sun exposure triggers a skin reaction. Ingredients in sunscreen, fragrances, antibiotic ointments, and cosmetics may lead to this type of sun allergy. Certain types of prescription medications also may trigger a photoallergic eruption, including certain antibiotics, diuretics, and medications for mental health conditions. Symptoms of PMLE typically develop within several hours. Symptoms of photoallergic eruption may not appear until one or two days.

Protecting the skin from sun exposure is an important preventive measure. It is important to be aware of medications that are likely to cause a photoallergic eruption. For mild symptoms of PMLE, cool compresses and a nonprescription antihistamine, such as diphenhydramine, may be useful in alleviating itchiness. A topical steroid cream or a prescription-strength antihistamine may be prescribed for more severe symptoms.