Alpha-Gal Syndrome
Alpha-Gal Syndrome

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ALPHA-GAL SYNDROME: WHAT YOU NEED TO KNOW ABOUT THIS TICK-RELATED ALLERGY

Learn what alpha-gal syndrome is, how it’s related to tick bites and tips for protecting your family during adventures outdoors.

  • Why Is It Important to Be Aware of Alpha-Gal Syndrome?

    If you love spending time outdoors, you may want to know more about alpha-gal syndrome (AGS), the emerging allergy linked to tick bites. In the United States, around 450,000 individuals may be affected with an alpha-gal allergy. From 2010 to 2022, there were more than 110,000 suspected cases. However, the full number is unknown since AGS isn’t a nationally reportable condition to the Centers for Disease Control and Prevention (CDC).1,2 When it comes to enjoying outdoor adventures, it’s crucial to be aware of this tick-related allergy so that you and your family are prepared.

  • What Is Alpha-Gal Syndrome?

    Also known as the red meat allergy, tick bite meat allergy or mammalian meat allergy, alpha-gal syndrome is an allergic condition that, in the United States, most commonly develops after a lone star tick bite.1,2,8 Alpha-gal itself is a sugar molecule naturally found in most mammals, but not in humans. When alpha-gal enters a person’s bloodstream, they may experience a sensitivity to it, which means an allergic reaction after eating red meat or other products made from mammals.1,3,4

  • How Is Alpha-Gal Syndrome Related to Ticks?

    In the United States, alpha-gal syndrome typically starts with the bite of a lone star tick.8 The ticks feed on mammals, like cows, pigs, deer, sheep or rabbits, where they acquire the alpha-gal molecule. Then, when the tick carrying alpha-gal bites a human, they release the molecule, exposing the person’s immune system to it. In reaction, the person may develop an allergy to red meat and other products made from mammals.1 , 3 , 4 Individuals with AGS can't transmit the condition to other humans, so the tick bite allergy isn’t contagious between people.

    Other species of ticks can also carry alpha-gal, including deer ticks, Western black-legged ticks and Asian long-horned ticks.2,9,10 You can identify lone star ticks by the single white spot on the back of adult females. They’re also larger than other ticks, reaching up to 5mm in size.6 Learn more about common types of ticks and what they look like in this article.

  • What Allergy Does Alpha-Gal Syndrome Cause?

    Not everyone bitten by a lone star tick will experience a meat allergy from ticks, and for those who do, the specific triggers can vary.12,13 Most commonly, individuals with alpha-gal syndrome have an allergic reaction after eating red meat. Poultry, eggs, fish and other seafood don’t contain alpha-gal, but it’s found in meat from mammals, including beef, pork, lamb, venison and rabbit.1 Sensitive individuals may also react to dairy products, gelatin (made from beef or pork), meat-based stock or foods cooked with animal-based fats.3

  • What Are the Common Alpha-Gal Symptoms?

    When individuals with alpha-gal syndrome consume these products that come from mammals, they may experience an allergic reaction. These symptoms may develop weeks or even months after the tick bite occurs, which can make it difficult to determine the cause. To diagnose AGS, healthcare professionals review symptoms and medical history. They may also order a blood test to detect antibodies specific to alpha-gal.1

    Possible symptoms of alpha-gal syndrome include:
    • Hives or itchy rash
    • Nausea or vomiting
    • Heartburn or indigestion
    • Diarrhea
    • Cough, shortness of breath or difficulty breathing
    • Anaphylaxis
    • Drop in blood pressure
    • Swelling of the lips, throat, tongue or eye lids
    • Dizziness or faintness
    • Severe stomach pain
    Currently, there isn’t a cure for AGS, and typically, it isn't fatal. Affected individuals can avoid red meat and other products containing alpha-gal to help manage symptoms. However, in rare cases, it can be life-threatening if an individual experiences anaphylaxis, particularly if the AGS is undiagnosed or if emergency treatment is delayed. If you suspect you have AGS, consult a healthcare provider for evaluation and guidance.1

  • Who May Be Concerned About Tick Exposure Outdoors?

    With the possibility of AGS in mind, it’s important to be prepared to face the prospect of tick exposure when enjoying outdoor activities, from hiking, camping, hunting or fishing to yardwork, gardening, dog walking or relaxing at the park. Currently, the lone star tick is most commonly found in the midwestern, southern and northeastern parts of the United States.5 If you and your family are planning an outdoor adventure, it’s important to be aware of potential tick exposure and take precautions to protect yourself.

  • How to Avoid Tick Bites Outdoors?

    When facing potential tick exposure outdoors, wear long pants and high socks with boots or closed-toe shoes. Stick to the middle of the path when hiking or biking, avoiding the edges where ticks may hide in tall grass.

    The CDC recommends applying an EPA-registered insect repellent with one of the following active ingredients: DEET, picaridin, IR3535, oil of lemon eucalyptus (OLE), para-methan-diol (PMD) or 2-undecanone.14 Always follow the directions for use on any product you use and reapply as directed. For more protection, treat your clothing and gear with a permethrin-based product.

    After spending time outdoors, check for ticks. Examine your clothing and equipment before entering your home and wash clothes on high heat. Don't forget to check your pets too! Find more advice on preparing for tick exposure outdoors in this article.

    Don’t let ticks prevent you and your family from delighting in outdoor activities. Take measures to be aware and prepared so that you can focus fully on enjoying your adventure.

Footnotes:

  1. CDC. About Alpha-gal Syndrome. Centers for Disease Control and Prevention. 2026. https://www.cdc.gov/alpha-gal-syndrome/about/
  2. De La Fuente, J., Pacheco I., Villar M., Cabezas-Cruz A. The alpha-Gal syndrome: new insights into the tick-host conflict and cooperation. Parasites & Vectors. 2019;12(1). Retrieved from: https://dx.doi.org/10.1186/s13071-019-3413-z.
  3. CDC. Fast Facts: Products That May Contain Alpha-gal. Centers for Disease Control and Prevention. 2026. [Retrieved from: https://www.cdc.gov/alpha-gal-syndrome/data-research/products-containing-alpha-gal/index.html.
  4. Platts-Mills, T.A.E., Li R.-C., Keshavarz B., Smith A.R., Wilson J.M. Diagnosis and Management of Patients with the α-Gal Syndrome. The Journal of Allergy and Clinical Immunology: In Practice. 2020;8(1):15-23.e1. Retrieved from: https://dx.doi.org/10.1016/j.jaip.2019.09.017.
  5. CDC. Regions Where Ticks Live. Centers for Disease Control and Prevention. 2011. [updated 2022. Retrieved from: https://www.cdc.gov/ticks/about/where-ticks-live.html.
  6. TickEncounter. Kingston, RI: University of Rhode Island. 2023. [Retrieved from: https://web.uri.edu/tickencounter/fieldguide/id-guide/.
  7. Houchens, N., Hartley S., Commins S.P., Claar D., Saint S. Hunting for a Diagnosis. New England Journal of Medicine. 2021;384(5):462-7.
  8. Commins, S.P., James H.R., Kelly L.A., Pochan S.L., Workman L.J., Perzanowski M.S., et al. The relevance of tick bites to the production of IgE antibodies to the mammalian oligosaccharide galactose-α-1,3-galactose. Journal of Allergy and Clinical Immunology. 2011;127(5):1286-93.e6. Retrieved from: https://dx.doi.org/10.1016/j.jaci.2011.02.019.
  9. Crispell, G., Commins S.P., Archer-Hartman S.A., Choudhary S., Dharmarajan G., Azadi P., et al. Discovery of Alpha-Gal-Containing Antigens in North American Tick Species Believed to Induce Red Meat Allergy. Frontiers in Immunology. 2019;Volume 10 - 2019. Retrieved from: https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2019.01056.
  10. Saunders, E.F., Sohail H., Myles D.J., Charnetzky D., Ayres B.N., Nicholson W.L., et al. Alpha-Gal Syndrome after Ixodes scapularis Tick Bite and Statewide Surveillance, Maine, USA, 2014–2023. Emerging Infectious Diseases. 2025;31(4). Retrieved from: https://dx.doi.org/10.3201/eid3104.241265.
  11. MFMER. Alpha-gal syndrome. Mayo Foundation for Medical Education and Research. 2022. [Retrieved from: https://www.mayoclinic.org/diseases-conditions/alpha-galsyndrome/symptoms-causes/syc-20428608.
  12. Thompson, J.M. Geographic Distribution of Suspected Alpha-gal Syndrome Cases—United States, January 2017–December 2022. MMWR Morbidity and Mortality Weekly Report. 2023;72
  13. Commins, S.P., Jerath M.R., Cox K., Erickson L.D., Platts-Mills T. Delayed anaphylaxis to alpha-gal, an oligosaccharide in mammalian meat. Allergology International. 2016;65(1):16-20. Retrieved from: https://www.sciencedirect.com/science/article/pii/S1323893015001975.
  14. CDC. Preventing tick bites. Centers for Disease Control and Prevention. 2024. [Retrieved from: https://www.cdc.gov/ticks/prevention/?CDC_AAref_Val=https://www.cdc.gov/ticks/avoid/on_people.html.