Cold urticaria associated with immunoglobulin M serum factor.

A case of cold urticaria, thought to be due to IgM, is presented. Passive transfer (PT) activity was manifested in cryoglobulin-free serum and in up to 20-fold dilutions of fraction I, the IgM-containing fraction obtained by Sephadex G-200 column chromatography. PT test results were positive with serum absorbed with cold agglutinins, and with heat-treated (56 degrees C, 4 hr) serum. These results were negative with cryoglobulin and after absorbing the supernatant of fraction I with anti-IgM. Skin adhesion time was within 24 hr. The in vivo histamine release during cold stimulation was recorded and in this patient, antihistamine administration proved the best method to alleviate the symptoms.