Clinical and immunological aspects of cutaneous vasculitis.

Thirty-five patients with cutaneous vasculitis were studied. Sixteen had raised serum levels of cryoglobulins. In all but one the cryoglobulin was an immune complex. Eleven patients had anticomplementary sera and five had a low serum IgM. Clinically, the cryoglobulinaemic patients were not readily distinguishable from the non-cryoglobulinaemic in that cold sensitivity occurred in only six of sixteen patients with cryoglobulins. Peripheral neuropathy and lesions in the upper respiratory tract were confined to those with cryoglobulinaemia. An immunopathological classification for the purpuric vasculitides is suggested.