Alpha-Gal Meat Allergy
Alpha-gal allergy is a syndrome that was first described in 2009 as a delayed anaphylaxis to red meat, specifically an excessive IgE antibody response to an oligosaccharide epitope, galactose-alpha-1,3-galactose. This reaction typically occurs about three to eight hours after eating red meat. As with other food allergies, the prominent symptoms can include severe itching and hives and in severe cases may lead to anaphylaxis (an extreme allergic reaction with symptoms such as tongue or throat swelling and vomiting) which can be fatal without proper medical attention.
There is significant evidence that the lone star tick can inject the alpha-gal carbohydrate molecule into the human upon tick bite, thereby leading to an excessive production of IgE antibodies. Because red meat also carries the alpha-gal molecule, there is a risk of an allergic response when that individual is once again exposed to alpha gal when he/she eats meat. This connection was established by a study by Commins and Platts-Mills where anaphylaxis occurred more often among those reporting a tick bite in the prior four weeks (2013). While mammalian meat products do trigger this potentially dangerous delayed allergic response, it is important for the public to know that poultry and fish do not. Although the lone star tick has been primarily found in the south and central U.S., its geographic range has expanded to include the northeast as well; thus, both patients and physicians should be informed of the risk of allergic reactions to red meat products after a lone star tick bite. There is emerging evidence that this allergic reaction to red meat subsides over one to five years in most affected individuals.