Hypersensitivity vasculitis.

This heterogeneous group of disorders is characterized by inflammation of small blood vessels. Hypersensitivity vasculitis may occur as a primary disease or in association with an underlying illness such as a connective tissue disorder or malignancy. Patients show any one of a number of different skin lesions; visceral organ involvement may also be present. The prognosis is generally good. Remission may be hastened by a brief course of corticosteroids.