Sometimes exposure to sun can cause sun allergy or sun poisoning. It usually develops within minutes to hours after you’ve spent time in the sun. It is not known why some people have sun allergies and others don’t, though genetics may play a part.
There are different signs and symptoms with sun allergy or sun poisoning, and a variety of skin manifestations. You might have patchy red skin, or you might have tiny red bumps. Sometimes the reaction looks like hives or blisters, sometimes the skin gets scaly or crusty, and sometimes there is itching and pain.
If your sun allergy or sun poisoning symptoms do not diminish or if they get more intense, contact your dermatologist for skin care suggestions or a prescription steroid.
Usually, a sun allergy or sun poisoning diagnosis is made simply by your dermatologist looking at your skin, though sometimes a diagnostic test may be necessary. In that case, your dermatologist may use an ultraviolet light test, or phototesting. Another diagnostic tool is photopatch testing, which can help determine if your sun allergy is triggered by something you apply to your skin.
If there is a concern by your dermatologist that your sun allergy symptoms may be caused by an underlying condition, you might require blood tests and skin samples to help to detect and diagnose.
Mild cases usually clear up on their own, simply by staying out of the sun. More intense cases may require steroid therapy. Your dermatologist might prescribe a corticosteroid cream, or if your skin reaction to the sun is more severe, you might be prescribed a dose of corticosteroid pills.
Always try to limit your time in the sun and avoid direct sun between 10 am and 4 pm, if possible. Use a broad-spectrum sunscreen with an SPF of at least 15 and reapply throughout the day (every two hours, if you are in the sun and/or swimming).