Diagnosis and Management of Patients with the α-Gal Syndrome

Abstract

The galactose-α-1,3-galactose (α-Gal) syndrome has many novel features that are relevant to diagnosis and management. In most cases, the diagnosis can be made on a history of delayed allergic reactions to mammalian meat and the blood test for IgE to the oligosaccharide α-Gal. In general, the diagnosis also dictates the primary treatment, that is, avoiding mammalian meat and also dairy in some cases. In the United States, the lone star tick is the primary cause of this disease, but different ticks are responsible in other countries. Blood levels of IgE to α-Gal often drop in patients who avoid recurrent tick bites, but the rate of decline is variable. Similarly, the delay before reactions is variable and the severity of the allergic reactions is not predicted by the delay or the titer of specific IgE. Some mammalian-derived products such as heart valves, gelatin-based plasma expanders, and pancreatic enzymes are relevant to only select patient groups. A minority of cases may benefit from avoiding a wide range of products that are prepared with mammalian-derived constituents, such as gelatin. This review focuses on the nature of the syndrome, common challenges in diagnosis and management, and also gaps in our current knowledge that would benefit from additional investigation.

Keywords: Anaphylaxis; Glycolipids; IgE to oligosaccharide; Red meat allergy; α-Gal.

Fig 1.

The risk and also severity of reactions in the α-Gal syndrome relates to the amount of the oligosaccharide that is present in food, drugs or other therapeutics. The route of administration is relevant to the speed at which reactions occur, i.e. – intravenous administration is associated with rapid reactions whereas oral ingestion has delayed onset. Co-factors such as NSAIDS, exercise and alcohol can be additional risk modifiers. This schematic reflects clinical experience, as well as challenge studies and laboratory investigations.