Health Conditions A-Z Allergies Alpha Gal Syndrome and Red Meat Allergy By Carley Millhone Carley Millhone Carley Millhone is a writer and editor based in the Midwest who covers health, women's wellness, and travel. Her work has appeared in publications like SELF, Greatist, and PureWow. health's editorial guidelines Updated on April 26, 2023 Medically reviewed by Suzanne Fisher, MS Medically reviewed by Suzanne Fisher, MS Suzanne Fisher, RD, is the founding owner of Fisher Nutrition Systems. learn more Share this page on Facebook Share this page on Twitter Share this page on Pinterest Email this page In This Article View All In This Article Causes Symptoms Diagnosis Treatments Prevention FAQs epantha / Getty Images Alpha-gal syndrome (AGS) is a red meat allergy linked to tick bites, specially bites from the lone star tick. This tick can carry alpha-gal (galactose-α-1,3-galactose)—a sugar molecule found in the cells of many mammals we eat—that leads to allergic reactions in humans. People bitten by ticks will alpha-gal can build up an immune response to the molecule, causing them to experience mild to severe allergic reactions to red meat and other meat from mammals. While not as common, some people can also react to alpha-gal found in cow's milk products and gelatin. What Causes a Red Meat Allergy? People aren't born with an allergy to alpha-gal. You can develop an alpha-gal allergy if alpha-gal enters your bloodstream via an infected tick bite, which triggers your immune system to react to alpha-gal as a defense mechanism. These antibodies your body makes will remain in your system, and the next time you consume red meat that also contains alpha-gal, your body may combat it. The most common cause of alpha-gal syndrome is linked to lone star tick bites, which are active April to late August, and can be found from Oklahoma to Maine on shaded tall grass or the tips of low-lying branches and twigs. But not everyone bitten by a lone star tick will develop a red meat allergy. Ticks must have alpha-gal in their saliva when they bite you. While not as common, other ticks that can cause alpha-gal syndrome include: Blacklegged ticks (U.S.)Cayenne ticks (Central American)Asian longhorn ticks (Asia) Researchers are still determining why alpha-gal causes different levels of allergic reactions in different people, or why some people don't develop alpha-gal syndrome despite being exposed. However, studies have theorized that people may be more likely to develop alpha-gal syndrome if they have more than one tick bite. 15 Facts You Must Know About Ticks and Tick-Borne Illness Symptoms of Red Meat Allergy Alpha-gal symptoms can range from mild to life-threatening allergic reactions after eating red meat and animal products containing alpha-gal. Symptoms vary person-to-person, and some people with a red meat allergy don't have consistent allergic reactions. Some people may also be sensitive to food, medications, and self-care products that contain alpha-gal from gelatin and cow's milk. Red meat allergy symptoms usually occur 2-6 hours after eating red meat or other products that may contain alpha-gal. Research shows people often have allergic reactions at night, around 10 p.m. Symptoms of alpha-gal syndrome can include: Hives or itchy skin rash Nausea or vomiting Severe stomach pain Diarrhea Indigestion or heartburn Coughing or wheezing Swollen lips, tongue, throat, or eyelids Shortness of breath and difficulty breathing or swallowing Heart palpitations Feeling faint or dizzy Low blood pressure Heart palpitations Severe allergic reactions to alpha-gal can lead to anaphylaxis (aka anaphylactic shock). This life-threatening, whole-body allergic reaction can make your blood pressure drop dramatically and narrow your airways so you can't breathe. How Red Meat Allergy is Diagnosed An allergist typically diagnoses alpha-gal syndrome with an allergy blood test. During this test, a healthcare provider draws a blood sample from your arm and sends the sample to a lab. The blood is analyzed for high levels of alpha-gal immunoglobulin-E (IgE) antibodies—proteins your immune system creates to protect your body from allergic reactions. People considered positive for alpha-gal syndrome typically have alpha-gal IgE levels greater than 0.1 IU/mL. Your allergist will also discuss your medical history and perform a physical exam to identify signs of allergic reactions. They may also perform an allergy skin test to rule out other allergies. These tests involve dropping allergens on areas of the skin and then pricking the skin to see if the area develops a red bump after 15 to 20 minutes (a sign of an allergy). However, skin prick tests are unreliable in detecting beef, pork, or lamb allergies. They are not a standard method to test for alpha-gal syndrome. Allergies That Might Seem Surprising Available Treatments Treating alpha-gal syndrome involves managing allergic reactions and avoiding foods with alpha-gal. For example, avoiding red meat can help people prevent allergic reactions to alpha-gal and potentially lower antibody levels that cause the allergy. Most people with alpha-gal syndrome will need to restructure their diets to avoid the following meats: BeefVenisonLambGoatRabbitBuffaloPork While not as common, some people may need to avoid other foods and products that come from mammals with alpha-gal, these include: Cow's milk productsLard, tallow, or suetBovine collagenPork or beef gelatin (including gelatin-coated medications)Red meat broth and gravyLanolinVaccines containing gelatin, glycerin, magnesium stearate, or bovine extract If an allergic reaction does occur, your healthcare provider may suggest the following allergy treatments: Long-acting oral antihistamine: Daily medications that help relieve allergy symptoms for 8-12 hours, including Allegra (fexofenadine) or Xyzal (levocetirizine).Short-acting oral antihistamines: Medications taken when symptoms start for quick relief up to 4-6 hours, including Unisom and Benadryl (diphenhydramine).Oral cromolyn solution: Medication taken before meals to help treat gastrointestinal symptoms like diarrhea, vomiting, and upset stomach, including Gastrocrom (cromolyn).Epinephrine injection: An adrenaline shot that helps treat anaphylactic shock by relaxing airway muscles and tightening blood vessels, including EpiPen and Auvi-Q (both brand names of epinephrine injection). The exact reason isn't fully understood, but something in the cancer drug cetuximab (Erbitux) formula can cause allergic reactions in people with alpha-gal syndrome. People with a red meat allergy should also avoid medical products like pig and cow heart valves, monoclonal antibodies, heparin, and antivenoms made from animals with alpha-gal. How To Prevent Red Meat Allergy Preventing and avoiding tick bites is the best way to prevent alpha-gal syndrome. Some ways you can reduce your risk of tick bites include: Avoid areas of tall grass where ticks like to hide Treat clothing and outdoor gear with permethrin (an insecticide) Wearing pre-treated permethrin clothes while hiking or camping Check for ticks on your body and clothes after being outdoors Remove embedded ticks with fine-tipped tweezers (grabbing the tick close to the skin) Check your pets for ticks Mow your yard frequently and pick up leaves Frequently Asked Questions Is there a cure for alpha-gal syndrome? Unfortunately, there is no cure for alpha-gal syndrome. Instead, it must be managed with dietary changes and allergy management. However, limited research shows a small percentage of people who achieve negative alpha-gal antibody levels after five years or more could reintroduce red meat without issues. What foods and products should I avoid if I have alpha-gal syndrome? If you have alpha-gal syndrome, you should avoid red meat and other mammalian meats like beef, pork, venison, lamb, goat, rabbit, and buffalo. Some people may also need to avoid other products with alpha-gal, like cow's milk, cheese, lard, certain vaccines, and gelatin (including gelatin-coated medications). A Quick Review Alpha-gal syndrome is a red meat allergy caused by tick bites. People with alpha-gal syndrome develop antibodies that fight alpha-gal. As a result, people with the allergy have mild to life-threatening allergic reactions to red meat and alpha-gal-containing foods like pork, venison, cow's milk, and gelatin. The lone star tick in the southeastern U.S. is the most common cause of alpha-gal syndrome, but some cases are also inked to blacklegged ticks. If you suspect you have alpha-gal syndrome, talk to your healthcare provider. They can test your blood for antibodies and help you devise a plan to avoid alpha-gal products and manage allergic reactions. Was this page helpful? Thanks for your feedback! Tell us why! Other Submit 10 Sources Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Commins SP. Diagnosis & management of alpha-gal syndrome: Lessons from 2,500 patients. Expert Rev Clin Immunol. 2020;16(7):667-677. doi:10.1080/1744666X.2020.1782745 Crispell G, Commins SP, Archer-Hartman SA, et al. Discovery of alpha-gal-containing antigens in North American tick species believed to induce red meat allergy. Front Immunol. 2019;10:1056. doi:10.3389/fimmu.2019.01056 Centers for Disease Control and Prevention. Alpha-gal syndrome. Mitchell CL, Lin FC, Vaughn M, et al. Association between lone star tick bites and increased alpha-gal sensitization: evidence from a prospective cohort of outdoor workers. Parasites Vectors. 2020;13:470. doi:10.1186/s13071-020-04343-4 MedlinePlus. Allergy blood test. MedlinePlus. Allergy skin test. Centers for Disease Control and Prevention. Products that may contain alpha-gal. Croglio MP, Commins SP, McGill SK. Isolated gastrointestinal alpha-gal meat allergy is a cause for gastrointestinal distress without anaphylaxis. Gastroenterology. 2021;160(6):2178-2180.e1. doi:10.1053/j.gastro.2021.01.218 Young I, Prematunge C, Pussegoda K, Corrin T, Waddell L. Tick exposures and alpha-gal syndrome: A systematic review of the evidence. Ticks Tick Borne Dis. 2021;12(3):101674. doi:10.1016/j.ttbdis.2021.101674 Centers for Disease Control and Prevention. Ticks.