Several years ago, doctors began treating people who arrived in emergency rooms with a delayed, strange and unexpected meat allergy. Patients might awaken in the middle of the night with terrible hives or trouble breathing. Most allergic reactions happen quickly, but these individuals were reacting to having spare ribs or a hamburger for supper hours earlier. What’s more, the initial trigger for this potentially life-threatening delayed reaction could have happened days or weeks earlier. It turned out that people bitten by a lone star tick were the ones who experienced this phenomenon called alpha-gal allergy.
Alpha-Gal–An Unexpected Meat Allergy:
Q. I was diagnosed with alpha-gal allergy a year ago. The symptoms appeared a few hours after eating beef and I eventually had a blood test that was diagnostic. I never saw a tick on my skin, but I did have a severe case of chiggers before I started to have reactions to beef. Can chiggers also cause this reaction?
A. We first heard about alpha-gal allergy nearly a decade ago. (You can listen to our initial interview about it here.) People were showing up at hospitals with unusual symptoms, often in the middle of the night. Many awakened with abdominal pain, nausea and diarrhea (Journal of Allergy and Clinical Immunology, Feb. 2009). Some also experienced an itchy skin rash, sneezing, breathing problems and swelling of the face, lips or tongue. These reactions are potentially life threatening.
Researchers eventually traced this unexpected meat allergy to the bites of lone star ticks (Amblyomma americanum). The tick transmits an alpha-gal molecule into humans when it bites them. The tick’s saliva carrying the alpha-gal molecule (technically termed galactose-alpha-1,3-galactose) triggers an immune reaction. Meat from mammals such as cows, pigs, lamb, rabbits and deer contain alpha-gal. Eating such meat can cause a bad reaction a few hours later.
Could Chiggers Trigger Alpha-Gal Allergy?
There is now some research to suggest that bites from chiggers (aka, redbugs, harvest mites, etc.) can also trigger this alpha-gal meat allergy (Journal of Allergy and Clinical Immunology. In Practice, Feb. 2019). After being bitten, a person can prevent a reaction only by avoiding mammalian meat. (Poultry and fish do not result in such a reaction. For some sensitive people, dairy products do result in a response.) You can learn much more about this condition by listening to our free podcast of Show 1167: Will a Tick Bite Make You Allergic to Meat?
