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. Author manuscript; available in PMC: 2022 Jul 22.
Published in final edited form as: N Engl J Med. 2021 Feb 4;384(5):462–467. doi: 10.1056/NEJMcps2017588

Figure 1. Sensitization and Mechanism Leading to Clinical Appearance of Alpha-gal Syndrome.

Figure 1.

The current hypothesis is that a person is bitten by a lone star tick that has had a previous blood meal containing galactose-alpha-1,3-galactose (alpha-gal). Alternatively, some evidence suggests that alpha-gal can be passed through tick life stages or may be present endogenously in tick saliva. After a period of time, IgE to alpha-gal develops. Once IgE to alpha-gal populates effector cells, the ingestion of red meat can trigger reactions. Alpha-gal that is contained in glycolipids is suspected to be the triggering antigen, and the slow gut absorption of lipid accounts for the delay in reaction. Some patients have only one symptom such as hives or gastrointestinal distress, but most report multiple symptoms.