urticaria. Close-up of urticaria on the limb of an 18-year-old female patient. Urticaria,also known as nettle rash or hives,is a skin condition in which a rash of itchy wheals or lumps develops on the skin,usually on the trunk or limbs. The wheals appear in a matter of minutes and usually fade after a few hours. Urticaria most often occurs as an acute allergic response,triggered,for instance,by particular foods or drugs. It can also result from heat,cold,sunlight or,less frequently,other medical conditions like cancer |