Monoclonal gammopathy in association with allergic disorders of the skin and respiratory tract

Monoclonal gammopathy is a condition characterized by the abnormal proliferation of a single clone of plasma cells, which produces a homogeneous monoclonal protein. It has been reported to occur in association with urticaria in the context of Schnitzler's syndrome and also has been observed to occur in angioedema with acquired C1 esterase inhibitor deficiency. We report 11 cases of monoclonal gammopathy presenting to practicing allergists (>2.5% of those screened) primarily in association with dermatologic disorders, i.e., urticaria, angioedema, and nonspecific dermatitis, but also with allergic respiratory disorders, i.e., allergic rhinitis, chronic sinusitis, and asthma. Most of the patients with dermatologic manifestations had respiratory disorders as well, three with chronic sinusitis. To our knowledge, these are the only such cases reported in patients with urticaria or angioedema in the absence of Schnitzler's syndrome or C1 inhibitor deficiency or in association with chronic sinusitis, allergic rhinitis, or asthma. Monoclonal gammopathy, angioedema, urticaria, allergic respiratory disorders, and sinusitis could be linked through antigenic stimulation as a trigger, either infectious, as in chronic sinusitis; self-antigens, as in autoimmunity; or the monoclonal gammopathy itself, causing idiotype-anti-idiotype immune complexes and inflammatory disease. The allergist, dermatologist, otolaryngologist, and primary care physician should all maintain a high index of suspicion for the occurrence of monoclonal gammopathy in the "allergic" population. Serum protein electrophoresis and/or serum immunofixation are useful screening tools. When monoclonal gammopathy is found, the presence of light chains in the urine should be assessed and the patient should be referred for prompt hematology-oncology evaluation with periodic monitoring for the development of plasma cell dyscrasias. Additional prospective study is necessary to determine the true prevalence of monoclonal gammopathy in the population presenting to the practicing allergist.