The following article was published on the Allergy Insider Website, July 2022.

10 New and Surprising Facts About Alpha-Gal Syndrome

By Linda Armstrong; Medically reviewed by: Fabio Iachetti, MD; Eva Södergren, PhD, MSc

What is alpha-Gal syndrome (AGS)?

Alpha-Gal Syndrome is just plain weird. And the more we learn about it, the stranger it seems to get. Also known as “red meat allergy,” “mammalian meat allergy,” or “tick-bite allergy,” the syndrome is when an allergic reaction to alpha-Gal, which is a sugar molecule found in mammal meat such as beef, pork, venison, and more.1-2 But this reaction actually begins with a bite from a lone star tick (or possibly a chigger).2-3

No, really. It’s not a made-up disease.

It works like this: The tick (or chigger) feasts on a mammal such as a deer, and in doing so, it ingests alpha-Gal. If it bites a human, it can transmit this molecule into the person’s bloodstream.2-3 This can then trigger an allergic reaction if they eat any mammalian products. The reaction can range from mild to severe and even life-threatening symptoms.2 However, eating other types of meats like poultry, fish, and shellfish won’t cause alpha-Gal Syndrome symptoms.

Alpha-Gal Syndrome symptoms include:2

  • Hives
  • Sneezing
  • Stomach pain
  • Diarrhea
  • Wheezing or shortness of breath
  • Vomiting
  • Nausea
  • Anaphylaxis

Rather than happening soon after eating (as is the case with many food-related allergies), an alpha-Gal allergy symptoms typically don’t occur for three to six hours after eating red meat or other mammalian products.Therefore, this delayed response may leave some asking, “What did I eat that caused my allergic reaction?”