What is solar urticaria?

Solar urticaria is a rare form of urticaria that develops on parts of the skin which have been exposed to sunlight. More detail about urticaria is available in another article.

Urticaria is caused by fluid leaking into the skin, and tends to form swollen, pale coloured wheals. In solar urticaria, they may appear only a few minutes after exposure to the sun. The skin may become reddened, itchy, or might sting as well. The wheals will go away once sun exposure ceases.