A peculiar cause of anaphylaxis: no more steak? The journey to discovery of a newly recognized allergy to galactose-alpha-1,3-galactose found in mammalian meat.

In recent years, a newly recognized allergic disease has been uncovered, and seemingly idiopathic causes of anaphylaxis now have an explanation. Individuals bitten by the lone star tick may develop IgE antibodies to the carbohydrate galactose-α-1,3-galactose (alpha-gal). Upon exposure of sensitized subjects to mammalian meat containing alpha-gal on glycoproteins or glycolipids, delayed anaphylaxis may ensue, often three to six hours after ingestion.1 Many of these individuals have negative allergy skin prick tests to meat, further obscuring the diagnosis. With the recent development of IgE alpha-gal tests, the clinical diagnosis can be confirmed in the laboratory.