Prevalence of Chronic Autoimmune Urticaria among Patients with Chronic Urticaria

Abstract

Urticaria is characterized by appearance of recurrent crops of evanescent, elevated, erythematous and itchy areas referred to as wheals. The causes and types of urticaria are varied, however, the wheal represents the basic and characteristic lesion for all types.

Urticaria is classified into acute ordinary urticaria, chronic ordinary urticaria and special types of urticaria as physical urticaria and urticarial vasculitis. Physical urticaria is caused by physical agents like heat (heat urticaria), cold (cold urticaria), pressure (pressure urticaria), sun (solar urticaria) or firm stroking (dermographism). Urticaria may follow cholinergic or adrenergic stimulation (cholinergic and adrenergic urticaria). It may occur after contact with water (aquagenic urticaria) or with any other chemical substance (contact urticaria). Urticaria following deposition of immune complex in blood vessels is called urticarial vasculitis. In this condition wheals last more than 24 hours, are painful rather than itchy and disappear leaving bruises or petichae. Biopsy