Leucocytoclastic vasculitis: an update for the clinician.

Leucocytoclastic vasculitis is a small vessel inflammatory disease mediated mostly by deposition of immune complexes. Infections, medications, chemicals, bacteria, viruses, and diseases associated with immune complexes have been accused in the pathogenesis. Cutaneous leucocytoclastic vasculitis presents as palpable purpura most often localized in the lower extremities, often accompanied by abdominal pain, arthralgia and renal involvement. The clinical diagnosis of leucocytoclastic vasculitis is confirmed histopathologically by skin biopsy. In order to determine the cause of the disease, depending on the patient's history, complete blood cell count, blood cultures, cryoglobulins, serum protein electrophoresis, rheumatoid factor, antinuclear antibody, and autoantibodies to neutrophilic cytoplasmic antigens and complement should be checked. Once the diagnosis of leucocytoclastic vasculitis is made, emphasis should be on the search for an etiological factor and the identification of the involved organs. If possible, the underlying cause should be treated or removed, for example discontinuation of drugs. The prognosis depends on the disease that has the cutaneous leucocytoclastic angiitis as a component, as well as the severity of internal organ involvement. For example, a patient with cutaneous leucocytoclastic angiitis and moderate nephritis as component of Henoch-Schonlein purpura has a much better prognosis than a patient with these same findings as a component of Wegener's granulomatosis. Only if physicians recognize and report severe reactions to regulatory authorities and manufacturers, new drugs associated with a risk of such reactions can be identified.