What is Alpha-Gal?
The reaction is a systemic release of antibodies that binds to a carbohydrate present in mammalian meat called galactose-alpha-1,3-galactose (alpha-gal). Mammalian meat is any meat that comes from a mammal including beef, pork, lamb, venison, goat and bison. Fish, turkey and chicken are not mammals, so they don’t have alpha-gal. When a person with the alpha-gal antibody eats mammalian meat, the meat triggers the release of histamine, a compound found in the body that causes allergic symptoms like hives, itching and even anaphylaxis.
Since the reaction to eating mammal meat is delayed by several hours, the proper diagnosis is often missed or misdiagnosed. People who are afflicted with the Alpha-Gal allergy have to be constantly vigilant about the ingredients they consume, because an allergic reaction can be severe and life-threatening.
For reasons yet unknown, researchers think the bite from a Lone Star tick exposes humans to a sugar from its gut called galactose-alpha-1,3-galactose, or “Alpha-Gal.” In some cases, the human immune system develops an allergic response to that sugar. Because Alpha-Gal is also found in red meat, a bite by the Lone Star tick may translate to an allergic reaction to anything from beef hamburgers to bacon. Repeated tick bites can potentially cause the antibody level of Alpha-Gal to rise, worsening reactions. People with the allergy can go into a delayed anaphylactic shock, four to six hours after eating red meat.
Alpha-gal allergy is different from other food allergies like the peanut allergy as the response is delayed. Unlike someone with a peanut allergy who has an immediate allergic response after eating peanuts, people with the alpha-gal allergy do not start having symptoms until several hours after they eat mammalian meat. When it comes to allergies, the human immune system has a “memory”. Proteins found in peanuts and eggs trigger the immune system much faster than the proteins found in Alpha-Gal sugar, which takes significantly longer for the immune system to recognize. There seems to be a correlation between the amount of meat eaten and the fat content of the food. There seems to be a correlation with metabolism of the fat, which explains the red meat allergy’s delayed reaction.
The Lone Star Tick
The Lone Star (Amblyomma americanum) tick is a medium-sized, reddish-brown tick that’s common in the Southeastern United States. It gets its name from a white dot found on the backs of all female adults. Lone Star ticks “bite” by inserting needle-like mouth parts into the skin, while backward-facing teeth act as hooks, securing them in place. They also secrete a cement-like substance that helps them to stay attached.
Signs & Symptoms
Signs and symptoms of a severe allergic reaction and anaphylaxis typically includes truncal hives, but may also include swelling, vomiting, diarrhea, trouble breathing and a rather significant (and quick) drop in blood pressure. Be sure to dial 9-1-1 for anyone who is having trouble breathing — especially if you suspect anaphylactic shock!
Treatment
Though there is no exact indication of how long the allergy to red meat lasts, it’s possible that it may improve over time. Avoiding repeated tick bites is the key, as your antibody levels should diminish. The obvious answer here as far as prevention of anaphylaxis (for those who have the Alpha-Gal allergy) is to stay away from red meat such as beef, pork, lamb, venison, goat and bison, and stick to a diet of chicken, seafood and turkey. Some but not all patients need to avoid milk, cheese, and real butter.