Lichen planus and discoid lupud erythematosus. Overlap syndrome associated with cryoglobulinemia and hypocomplementemia.

A patient with the discoid lupus erythematosus and lichen planus overlap syndrome has profound depression of serum C4 concentration associated with substantial mixed cryoblobulinemia. A family study failed to disclose evidence of a familial hypocomplementemia, cryoglobulinemia, or a dermatologic condition. Immunologlobulin, but no complement, was detected at the site of the skin abnormality. This case illustrates an immune-complex disorder with a mixed cryoglobulinemia that is related to immunoglobulin deposition in the skin.