α-Gal Syndrome: Busting Paradigms in Food Allergy.

α-Gal syndrome, also known as red or mammalian meat allergy, results from immunoglobulin E-mediated hypersensitivity responses to the carbohydrate galactose-α-1,3-galactose (α-gal). Patients with α-gal syndrome experience immediate onset of allergic symptoms following the injection of pharmaceutical products containing α-gal. However, it typically takes 2 hours or more after dietary α-gal ingestion before patients with α-gal syndrome experience immunoglobulin E-mediated hypersensitivity responses. The case report by Heffes-Doon and colleagues highlights the lack of official guidelines on when and how to reintroduce mammalian meat products into the diet when there is clear laboratory evidence of declining α-gal immunoglobulin E levels.