What is a sun allergy?
(Image credit: Tim Robberts via Getty Images)
When you think of the sun’s impact on the skin, sunburn and skin cancer are probably the first things that come to mind. But did you know that you can actually be allergic to the sun as well? It’s true!
Ultraviolet light from the sun is the cause of sun allergies, resulting in an itchy rash that shows up as red bumps, red patches, blisters or hives on sun-exposed areas of the skin, according to Dr. Debra Jaliman, a board-certified dermatologist based in New York and a member of the American Academy of Dermatology.
Sun allergies encompass several immune responses to ultraviolet light. Some sun allergies may be related to a person’s genetic makeup, while others can develop in response to certain chemicals in medications or cosmetics, according to Harvard Health.
Related: What causes allergies?
A rash like this one, here shown on fair skin, may appear about two hours after sun exposure in people with “polymorphic light eruption.” (Image credit: DermNetNZ via Wikimedia Commons)
One of the most common forms of sun allergy is polymorphic light eruption (PMLE), which tends to be more prevalent in the Northern Hemisphere. PMLE usually appears as a rash within two hours of sun exposure and is more common in women than in men. Its symptoms typically start in early adulthood; its cause is unknown, according to the medical resource StatPearls.
Actinic prurigo, another form of sun allergy, mainly affects Native American populations in the northern, southern and central U.S. with the rash usually beginning earlier and being more severe than in typical PMLE, Harvard Health noted.
Another common form of sun allergy is photoallergic eruption, a skin reaction triggered by an interaction between sunlight and chemicals ingested or applied to the skin. This rash may take one to two days to develop and can spread to areas of the skin that were not exposed to the sun, according to Harvard Health.