Alpha-gal allergy

Alpha-gal allergy is a type of food allergy that is triggered by the consumption of meat from mammals. The allergy is caused by a reaction to a carbohydrate called galactose-alpha-1,3-galactose, or alpha-gal for short. This carbohydrate is found in the meat of mammals, excluding primates, and is also present in some medications and vaccines.

Galactose alpha-1,3-galactose

Causes[edit | edit source]

Alpha-gal allergy is unique among food allergies because it is not triggered by a protein, but by a carbohydrate. The allergy is believed to be caused by a tick bite, specifically from the Lone Star tick (Amblyomma americanum). When a person is bitten by a tick that has previously fed on a mammal, the tick can transfer alpha-gal molecules into the person's bloodstream. This can cause the immune system to produce antibodies against alpha-gal, leading to an allergic reaction when the person later consumes meat containing alpha-gal.

Amblyomma americanum tick

Symptoms[edit | edit source]

The symptoms of alpha-gal allergy can range from mild to severe and can include hives, itching, swelling, abdominal pain, nausea, diarrhea, difficulty breathing, a drop in blood pressure, and anaphylaxis. Unlike most food allergies, which cause symptoms within minutes of consumption, alpha-gal allergy symptoms typically do not appear until three to six hours after eating mammalian meat.

Diagnosis[edit | edit source]

Diagnosis of alpha-gal allergy is typically made through a combination of patient history and blood tests. The blood tests look for the presence of alpha-gal antibodies in the patient's blood. A positive result indicates that the patient has been sensitized to alpha-gal and may experience an allergic reaction to mammalian meat.

Treatment[edit | edit source]

There is currently no cure for alpha-gal allergy. Treatment involves avoiding the consumption of mammalian meat and any medications or vaccines that contain alpha-gal. In cases where an allergic reaction occurs, treatment may include antihistamines, corticosteroids, and in severe cases, epinephrine.