The hives are a histamine reaction in response to<unk>  stimuli, including a drastic drop in temperature,<unk>  air, and<unk>  water. There are many causes for<unk>  hives, most are idiopathic (meaning they have no known cause). Some rare conditions can cause<unk>  hives, and it can be useful to test for these conditions if the<unk>  hives are in any way unusual. Scientists from the USA National Institutes of Health have identified a genetic mutation in three unrelated families that causes a rare immune disorder characterized by excessive and impaired immune function: immune deficiency, autoimmunity, inflammatory skin disorders and<unk> -induced hives<unk> . "The mutation discovered occurs in a gene for phospholipase C-gamma2 (PLCG2), an enzyme involved in the activation of immune cells. The investigators have named the condition PLCG2-associated antibody deficiency and immune dysregulation, or PLAID."
Cold urticaria
Heat urticaria
Solar urticaria
Pressure urticaria
Aquagenic urticaria
Physical urticaria
Cholinergic urticaria
Delayed pressure urticaria