Meat Allergy Caused By Tick Bites Becoming More Common In US, Experts Say

Key TakeawaysA meat allergy caused by tick bites is becoming more commonPeople testing positive for alpha-gal syndrome rose dramatically over the past decadeTick bites may cause people to develop an allergic reaction to a sugar molecule found in meat.TUESDAY, Nov. 4, 2025 (HealthDay News) — A once-rare meat allergy caused by tick bites is dramatically increasing across the United States, researchers said.There’s been a 100-fold increase in positive test results for the allergy, called alpha-gal syndrome, between 2013 and 2024, researchers reported last week at the American College of Gastroenterology’s annual meeting in Phoenix.“Alpha-gal syndrome is unlike any other food allergy we treat,” researcher Dr. Vinay Jahagirdar, a fellow with the Virginia Commonwealth University (VCU) Gastroenterology Fellowship Training Program and Stravitz-Sanyal Institute for Liver Disease and Metabolic Health, said in a news release.“Symptoms often appear several hours after a person eats red meat, making it difficult to connect a meal with an allergic reaction,” Jahagirdar said. Many patients are misdiagnosed or go years without answers.”AGS occurs when a tick bite causes a person’s immune system to develop an allergic reaction to a sugar molecule found in beef, pork or lamb called galactose-alpha-1,3-galactose, or alpha-gal, researchers said.Symptoms from an alpha-gal allergic reaction can include hives, swelling, nausea, vomiting, abdominal pain, diarrhea or even life-threatening anaphylactic shock, researchers said.The syndrome typically is linked to bites from the lone star tick, researchers said. These ticks have expanded their range north and west in recent years, aided by warmer winters and growing deer populations.“Alpha-gal syndrome has gone from a medical curiosity to a major public health issue in just a decade,” Jahagirdar said. “Our study shows this is not a localized problem anymore. We’re seeing cases far beyond the Southeast, including in the Northeast and Midwest.”For the study, researchers analyzed records for more than 3,800 adults tested for alpha-gal antibodies between 2010 and 2025.The study showed a sharp rise in positive test results:Overall, about a quarter (749) of the patients wound up diagnosed with alpha-gal syndrome.Across 69 U.S. health systems, alpha-gal syndrome incidence rose from about 1.8% of those tested in 2013-2014 to nearly 39% in 2021-2022.About 17% of alpha-gal cases also tested positive for Lyme disease, suggesting an overlapping risk from tick exposure.Most cases were reported from the Northeast (69%) and the South (23%).Gastrointestinal (GI) symptoms are among the most common signs of AGS, with people experiencing stomach pain, cramping, bloating, nausea, vomiting or diarrhea several hours after eating red meat or meat-based foods, researchers said.These reactions are delayed, frequently appearing three to six hours after a meal, and so are often mistaken for food poisoning or irritable bowel syndrome, researchers noted.There’s no cure for AGS, researchers said. Sufferers must avoid red meat and, in some cases, even products like dairy or gelatin.“The spread of ticks is bringing new allergic diseases to areas where doctors and patients may not expect them. Recognizing this connection is key to protecting public health,” researcher Dr. Ravi Vachhani, director of the VCU Gastroenterology Fellowship Training Program, said in a news release.Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.More informationThe U.S. Centers for Disease Control and Prevention has more about alpha-gal syndrome.SOURCE: Virginia Commonwealth University, news release, Oct. 30, 2025.What This Means For YouPeople who get sick after eating red meat should ask their doctor about alpha-gal syndrome, particularly if they’ve been bitten by a tick or live in a tick-infested area..Sign up for our weekly HealthDay newsletter