Sun allergy: Can you be allergic to the sun?

Yes, it is possible to have a sun allergy — although it is not a true allergy. In sensitive people, sun exposure activates inflammatory cells or proteins in the skin, which triggers hives (solar urticaria).

Certain medications and conditions also can cause increased sensitivity of the skin to sun exposure (photosensitivity). But in such cases, reactions are usually red rashes, not hives.

If you have sun allergy, you can reduce your risk of a reaction by:

• Limiting your time in the sun
• Wearing sunglasses and protective clothing when you're outside

Your doctor may also recommend the use of antihistamines to prevent or reduce a reaction. Using sunscreen may offer some protection. But sunscreens don't block out ultraviolet rays completely, so you may still experience a skin reaction.