Trouble Eating Red Meat? You Might Have a Tick-Borne Allergy

"It was more than 12 years ago, and I was out to dinner with friends, when one of them said, "Too bad I can't order any of the steaks." He went on to describe how, in the past year, he had noticed that every time he ate red meat, he developed itchy skin, nausea, and stomach pain a few hours later."

"AGS is a food allergy triggered by a sugar molecule (galactose-alpha-1,3-galactose) that is found in all mammals except humans and other primates. When ticks bite a person's skin, they can introduce this molecule into the human bloodstream, stimulating allergic antibodies (IgE) that persist. In the future, any exposure to meat-derived products (e.g., beef, pork, lamb, or even gelatin in capsules) could cause an allergic reaction. These allergic reactions to meat products start a few hours after exposure and range from mild upset stomach to anaphylaxis."

Alpha-gal syndrome is an IgE-mediated allergy directed against the sugar galactose-alpha-1,3-galactose, present in nonprimate mammals. Tick bites can introduce the molecule into the bloodstream, triggering persistent allergic antibodies that predispose to reactions on later exposure. Reactions typically occur three to six hours after ingesting mammalian meat or gelatin-containing products. Clinical manifestations range from hives, gastrointestinal upset, nausea, and stomach pain to severe anaphylaxis. The delayed timing frequently causes prolonged diagnostic delays and unexplained symptoms. Since 2009, tens of thousands of suspected cases have been recorded in the United States, with true incidence likely substantially higher.

Read at Psychology Today