Galactose-α-1,3-Galactose Allergy Is Not a Hitherto Unrecognized Cause of Chronic Spontaneous Urticaria.

Background: Tick bite-induced galactose-α-1,3-galactose (α-Gal) IgE and subsequent ingestion of red meat may cause delayed severe allergic reactions including urticaria, gastrointestinal symptoms or anaphylaxis. We tested the hypothesis that increased levels of IgE to α-Gal due to tick bites and the subsequent ingestion of red meat or meat products may possibly be an un(der)recognized cause of chronic spontaneous urticaria (CSU). Methods: Levels of IgE to α-Gal and total IgE were measured (ImmunoCAP, Phadia AB/Thermo Fisher Scientific) in 83 patients (61 female and 22 male, median age 43 years, range 18-82) from the Department of Dermatology and Allergy, Charite - Universitatsmedizin, Berlin, Germany. All had been clinically diagnosed with moderate-to-severe CSU of a median duration of 2.9 years (range 0.1-50). Results: Eighty of the 83 patients (96%) had undetectable (A/l) serum levels of IgE against α-Gal. The levels in the remaining 3 were all low (0.25, 0.4 and 3.1 kUA/l). In no patient, including those with measurable serum levels of IgE against α-Gal, was eating red meat associated with the development of symptoms of urticaria. Conclusion: Our results indicate that an allergic response to α-Gal is highly unlikely to be a hitherto unrecognized common cause of CSU.