You can be allergic to the sun. A sun allergy—sometimes also called photosensitivity—occurs when the skin is hypersensitive to ultraviolet (UV) rays, which the sun naturally emits. Signs of ...

The American College of Rheumatology (ACR) loosely defines photosensitivity as "a skin rash as a result of unusual reaction to sunlight." Beyond skin rashes that can develop, exposure to the sun can ...