Urticaria

Urticaria (from the Latin urtica, nettle, commonly referred to as hives, is a kind of skin rash notable for pale red, raised, itchy bumps. Hives are frequently caused by allergic reactions; however, there are many nonallergic causes. Most cases of hives lasting less than six weeks (acute urticaria) are the result of an allergic trigger. Chronic urticaria (hives lasting longer than six weeks) is rarely due to an allergy.