Urticarial erythema associated with IgA myeloma

We report a case of atypical urticaria associated with IgA multiple myeloma. A 79-year-old man presented with a two-month history of wheal-like erythema, which lasted approximately one week without any response to anti-histamines. Histological examination of a lesion revealed leukocytoclasia as well as perivascular leukocytic infiltration, being consistent with urticarial erythema. Laboratory investigation showed markedly elevated serum IgA concentration and M-protein in serum protein electrophoresis. A bone marrow examination led to a diagnosis of myeloma. An immunofluorescence study failed to detect any IgA deposit in the lesion. However, the wheal-like eruptions disappeared when the IgA myeloma was treated and reappeared when it relapsed. We conclude that this long lasting urticaria was the cutaneous manifestation of IgA myeloma.