Hives on the left chest wall. Notice that they are slightly raised.Hives Drawing of hives Hives, or urticaria, is a form of skin rash with red, raised, itchy bumps. They may also burn or sting. Welts (raised areas surrounded by a red base) from hives can appear anywhere on the surface of the skin. Whether the trigger is allergic or not, a complex release of inflammatory mediators, including histamine from cutaneous mast cells, results in fluid leakage from superficial blood vessels. Welts may be pinpoint in size or several inches in diameter. Often the patches of rash move around. About 20% of people are affected. Cases of short duration occur equally in males and females, lasting a few days and without leaving any long-lasting skin changes. Cases of long duration are more common in females. Cases of short duration are more common among children while cases of long duration are more common among those who are middle aged. Fewer than 5% of cases last for more than six weeks. The condition frequently recurs. In half of cases of hives, the cause remains unknown. Angioedema is a related condition (also from allergic and nonallergic causes), though fluid leakage is from much deeper blood vessels in the subcutaneous or submucosal layers. Individual hives that are painful, last more than 24 hours, or leave a bruise as they heal are more likely to be a more serious condition called urticarial vasculitis. Hives caused by stroking the skin (often linear in appearance) are due to a benign condition called dermatographic urticaria.
symptom of Eosinophilic granulomatosis with polyangiitis
medical diagnosis of Eosinophilic granulomatosis with polyangiitis
medical cause of Bronchiolitis obliterans
symptom of Idiopathic pulmonary fibrosis
symptom of Behçet's disease
symptom of Hereditary angioedema
complications of Vasculitis
complications of Behçet's disease