Vasculitis in chronic urticaria: an immunopathologic study.

Forty-five patients with chronic urticaria were studied to determine: (1) the histologic incidence of leukocytoclastic vasculitis and (2) the clinical, laboratory and immunopathologic parameters that characterized this patient group. By histopathologic examination a spectrum of changes were noted as 9 patients showed leukocytoclastic vasculitis, 15 a dense perivascular infiltrate of lymphocytes and eosinophils, and 21 only a sparse lymphocytic perivascular infiltrate. Both the vasculitis and the dense infiltrate groups had an increased incidence of circulating immune complexes, as detected by Clq binding and monoclonal rheumatoid factor inhibition radioassays. Direct immunofluorescence showed blood vessel deposition of immunoglobulins, complement, and/or fibrin in 33% of the vasculitis group, 13% of the dense infiltrate group, and 9% of the sparse infiltrate group. These studies suggest that a meaningful number of patients with chronic urticaria have histologic and immunopathologic findings of vasculitis.