Immunologically mediated skin disorders

Urticaria is characterized by transient, superficial well-defined pruritic wheals of the skin, whereas angioedema involves oedema of the dermis and subcutaneous or submucosal tissue that is deep and ill-defined. Acutely urticaria occurs in 20% of the population, whereas chronic urticaria and angioedema occur in 0.5%. Dermographism is evoked by skin stroking; pressure urticaria by application of weight to the skin; vibratory angioedema by a vibratory stimulus; cholinergic urticaria can be diagnosed by exercise to sweating; solar urticaria by testing with UVB, UVA, and visible light; cold urticaria by application of ice cube to skin. Second-line therapies could involve a short course of oral systemic corticosteroids for severe urticaria and urticarial vasculitis. A rare disorder with an incidence between 2.3 and 10 per million population, four times more common in females. A rare disease with an incidence of 1.9 per million, occurring twice as frequently in females as in males.