Alpha-Gal Allergy

Alpha-gal allergy**: A tick bite (especially from the Lone Star tick) can trigger an immune response to a carbohydrate called alpha-gal, found in red meat. While this response can cause a severe allergic reaction in some people after they consume red meat, it does not lead to septic shock. The allergic reaction can present with various symptoms such as hives, difficulty breathing, and gastrointestinal upset, which could be serious and warrant emergency treatment, but this is distinctly different from septic shock.

The allergy appears to be mediated by ticks, especially the Lone Star tick (Amblyomma americanum), as many individuals report having a history of tick bites prior to the onset of symptoms. It's believed that during a bite, ticks inoculate alpha-gal into the human host, triggering an immune response and potentially the production of IgE antibodies to alpha-gal. Manifestations of alpha-gal syndrome range from urticaria, angioedema, and abdominal distress, to more severe reactions such as anaphylaxis. The syndrome is unique due to the significant delay (3-6 hours) in symptom onset after ingestion of mammalian meat, compared to more typical food allergies, which usually produce symptoms within minutes to an hour after ingestion. Management usually entails strict avoidance of mammalian meat products, which can be challenging due to the hidden presence of alpha-gal in some food and pharmaceutical products. Consumers should also be educated to avoid tick bites, and Epinephrine autoinjectors should be prescribed by PCP for emergency management of anaphylaxis. Testing for alpha-gal syndrome typically involves identifying the presence of serum IgE antibodies to alpha-gal, through a procedure such as ImmunoCAP testing.

Call 911 or go to an ER, when there is a history of tick bites, and timing of symptoms after eating red meat. Identifying an alpha-gal allergy can be challenging as the allergic reaction is often delayed, occurring 3-6 hours after ingestion of mammalian meat products. The timing of this reaction can make it difficult for to associate symptoms, such as hives, itching, abdominal complaints, or even anaphylaxis, with the consumption of meat products. If one's history suggests an alpha-gal allergy, tan allergist ought to be conulted ASAP for further evaluation. Skin testing or an alpha-gal specific IgE blood test can be performed to confirm the diagnosis. In the meantime, it's crucial to avoid all mammalian meats like beef, lamb, and pork. If one has a history of severe allergic reactions, request an emergency epinephrine auto-injector prescription from a PCP/HCP. Management mainly involves strict dietary avoidance measures, vigilant food labeling reading since some medications and vaccines may contain alpha-gal, and tick prevention strategies, given the strong association between alpha-gal sensitivity and tick bites. CALL 911 to report any severe allergic reactions immediately, as anaphylaxis is a medical emergency.

https://www.medpagetoday.com/popmedicine/popmedicine/107404

Author

Paddy Kalish OD, JD and B.Arch