Lately, you may have noticed that when you go outside, you burn easier. A common sun allergy called polymorphous light eruption (PMLE) may be causing this. It is an immunologically mediated reaction to the sun, usually seen in the spring and early summer. The risk of PMLE increases when the skin has not been exposed to the sun for long periods of time and presents as itchy, burning red bumps or blisters. To protect yourself, slather on SPF before heading out, no matter what.