Cutaneous vasculitis: approach to diagnosis and systemic associations.

The starting point in the evaluation of vasculitis is the clinical examination. The character and location of the primary lesions determine the type of biopsy specimens and additional tests needed to classify vasculitis. The most common causes of cutaneous vasculitis are drug reactions, infectious diseases, reactions to inflammatory diseases such as rheumatoid arthritis or inflammatory bowel disease, or association with malignant disease, especially lymphoproliferative disorders. Direct immunofluorescent techniques and leukocyte monoclonal antibody studies are useful for the diagnosis of selected cases of vasculitis. The clinical and histopathologic data help delineate an approach for further investigation of potentially associated systemic disorders or underlying causes. Although some cases of cutaneous vasculitis are not associated with systemic disorders, this possibility should never be assumed but considered only as a diagnosis of exclusion after careful examination of each patient.