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.