Swelling of the feet and hands, often indistinguishable from angiooedema, occurs after activities such as weight lifting, walking, jogging, and running. During severe attacks, arthralgias and a flu-like illness may accompany the rash. Linear wheals appear as a result of scratching. It may also be symptomatic of porphyria cutanea tarda. Patients notice erythema, burning, and urticarial wheals within minutes following exposure to sunlight.
Wheals can develop anywhere on the body, mostly in the sun exposed skin.
The action spectrum of solar urticaria is broad, ranging from UVC, UVB, UVA to visible spectrum. Avoidance of sunlight is important. The body should be covered with clothing and the patient should be advised to use an appropriate sunscreen. Antihistamines can give symptomatic relief and may be helpful as a preventive measure if taken before sun exposure. Characteristic urticaria appears on exposed areas on a cold day.