Hyperimmunoglobulinemia E and efficacy of elimination diet in two patients with Schnitzler syndrome.

Background: Schnitzler syndrome (SS) is a rare clinical entity characterized by chronic recurrent urticarial rash, monoclonal IgM gammopathy, intermittent fever and other symptoms. In this report, we present the cases of two patients with SS: a male and a female aged 50 and 49 years, respectively. Both patients had hyperimmunoglobulinemia E and showed good response to elimination diet.
Methods: The patients had chronic urticaria, IgM gammopathy and an elevation of the serum levels of inflammation markers. Total IgE levels were found to be high (2000 U/ml and 540 U/ml, respectively). No underlying causes for hyperimmunoglobulinemia E (allergy, parasites, etc.) were revealed. The first patient did not respond to the treatment with antihistamines, while the second one responded only to high doses. The response to prednisolone in the second patient was incomplete.
Results: Following a strict elimination diet resulted in marked improvement in skin lesions in both patients. In one of our patients we observed a decrease in IgE and IgM levels after a 3 week diet. The systemic symptoms persisted and improved only after adding pefloxacin, followed by a 3-day empirical course of intravenous prednisone in the first patient and a course of plasmapheresis in the second one.
Conclusion: The high serum levels of total IgE may be associated with chronic urticaria activity, severe disease course and a poor response to treatment with antihistamines, and may be considered a possible marker of a subset of patients with SS showing a good response to the restriction diet. In general, we can assume that elimination diet can have an influence on the skin lesions and other symptoms of SS as well as on total IgE and IgM levels, but such association, the underlying mechanisms and the reasons for excessive IgE synthesis should be investigated in further studies.