Vegetating iododerma with underlying systemic diseases: report of three cases.

Three patients with vegetating iododerma as a result of potassium iodide therapy are presented. The first patient had polyarteritis nodosa, the second had monoclonal gammopathy of undertermined significance, and the third had multiple myeloma. Vegetating iododerma probably represents an idiosyncratic response to iodides; patients with polyarteritis nodosa and paraproteinemias may be predisposed.