What is Sun Allergy?

Sun allergy, or photosensitivity, is a collective term for conditions that cause a rash or other skin reactions after exposure to sunlight. The most common type is polymorphous light eruption (PMLE), which is an immune system reaction to sunlight.

A sun allergy is not a classic allergy, for example, like an allergy to peanuts or pollen. It's a photosensitive disorder where the immune system reacts incorrectly to changes in the skin caused by ultraviolet (UV) rays. This reaction leads to a rash and, although the exact cause is not fully understood, it is believed to be influenced by both genetic and environmental factors. Some forms of sun allergy can be caused by medications, fragrances, or other chemicals applied to the skin.

Types of Sun Allergy

Although PMLE is the most common type, there are other forms, each with its own characteristics:

• Polymorphous Light Eruption (PMLE): This is the most frequent form. It usually manifests as an itchy rash. Small, red bumps or blisters appear on parts of the body that are exposed to sunlight. The rash typically appears within a few hours or a day after sun exposure and mostly affects body parts that were covered in winter (e.g., chest, arms, and legs).

• Solar Urticaria: This is a rare condition that causes a rash similar to hives (urticaria) on the skin within minutes of sun exposure. The rash usually disappears within an hour of returning to the shade.

• Photoallergic Reaction: This occurs when a chemical applied to the skin (such as certain types of sunscreens, fragrances, or medications) reacts with sunlight. As a result, a widespread allergic reaction begins, which can damage both sun-exposed and covered skin.

• Actinic Prurigo: This is a rare, chronic, and intensely itchy rash that often begins in childhood and is more common in people of Native American or Latin American descent.

Symptoms

The symptoms of a sun allergy can vary depending on the type, but common signs are:

• Itching or burning in the rash area;

• Small bumps, blisters, or a rash similar to hives;

• Redness and inflammation;

• In some cases, skin peeling.

Rarely, more severe symptoms may appear, such as headache, nausea, or shortness of breath, especially in cases of solar urticaria.

Prevention and Treatment

The best way to manage a sun allergy is prevention.

• Sun Protection: Use a broad-spectrum sunscreen with at least SPF 30 and reapply it every two hours.

• Avoid Peak Sun Hours: Limit sun exposure, especially between 10 a.m. and 4 p.m.

• Protective Clothing: Wear long-sleeved shirts, long pants, and a wide-brimmed hat.

If a rash appears, mild cases often resolve on their own if you avoid sun exposure. To reduce itching and inflammation, you can use over-the-counter antihistamines. In more severe cases, you should definitely consult a doctor, who will choose the appropriate treatment.