Alpha-gal: a carbohydrate (galactose-alpha-1,3-galactose) that has been identified as the cause of an unusual meat allergy that develops after a tick bite. The alpha-gal compound is found in the meat of all non-primate mammals. The allergic symptoms appear to be related to having experienced a bite from the Lone star tick (Amblyomma americanum). Unlike tick-borne infectious diseases like Lyme disease and Rocky Mountain Spotted Fever, the alpha-gal reaction is a true allergic reaction to the alpha-gal compound in meat that develops in people who have had bites from this type of tick. It is not due to an infectious organism spread by the tick bite. The exact reason for the relationship to tick bites and development of the allergy is unknown. The Lone Star tick is found in the US, mainly in the southeast and up to Iowa and into New England.
Symptoms include those of other allergic reactions and occur following the consumption of any type of meat. They can include:
- Hives or skin rash
- Vomiting or diarrhea
- Runny or congested nose
- Worsening of asthma
Anaphylaxis, a severe and potentially deadly allergic reaction, is also possible. With alpha-gal allergy, the symptoms are not typical of many food allergies because they make take hours to develop in some people.
American College of Allergy, Asthma, & Immunology. "Types of Food Allergy: Meat Allergy."
Science Magazine. "Ticked Off About a Growing Allergy to Meat." Nov 16, 2012.