Alpha-gal Syndrome

Alpha-gal Syndrome (AGS) (also called alpha-gal allergy, red meat allergy, or tick bite meat allergy) is a potentially life-threatening allergic reaction to alpha-gal, which is a sugar molecule found in many mammals, but not in people. AGS symptoms occur after people eat red meat or are exposed to other products containing alpha-gal. Unlike typical food allergies, symptoms are often delayed by two hours or more after exposure and can arise suddenly following years of safe meat consumption. Individuals with AGS may experience different reactions and symptoms can range from mild to life-threatening. Common symptoms include hives or itching; abdominal pain, nausea, vomiting, or diarrhea; cough, shortness of breath, or wheezing; and swelling of the lips, throat, tongue, or eyelids. Anaphylaxis (a potentially life-threatening reaction involving multiple organ systems) may need urgent medical care. Alpha-gal is carried in the saliva of the lone star tick and other ticks typically after feeding on mammalian blood. Growing evidence suggests that AGS in the United States may be triggered by the bite of Amblyomma americanum (lone star tick) and Ixodes scapularis (black-legged tick). People that are bitten by these ticks, especially those that are bitten repeatedly, are at risk of becoming sensitized and can result in allergic reactions. Immediate symptoms such as hives or shortness of breath are treated the same as any other food allergy, in an urgent care setting with anti-histamines, epinephrine and other medications. Prevention involves avoiding tick bites, red meat and other alpha-gal containing products in sensitized individuals.

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Last Reviewed: 4/21/2022