A rare meat allergy triggered by tick bites, known as alpha-gal syndrome, may be spreading beyond its usual hotspots, experts warn. While the condition has long been linked to the lone star tick, two recent cases suggest other tick species in the U.S. may also be responsible, raising concerns that the allergy could emerge in new regions.
The alpha-gal syndrome occurs when a lone star tick bite transfers a sugar molecule called alpha-gal into the body, triggering an immune response. This can lead to mild to severe allergic reactions to red meat, such as beef, pork, and lamb. In some cases, it may also cause sensitivities to dairy products and gelatin.
According to estimates from the U.S. Centers for Disease Control and Prevention (CDC), more than 450,000 people in the U.S. may have alpha-gal syndrome. The lone star tick, which typically resides in the southeastern United States, was believed to primarily affect travelers or residents exposed to these regions. An earlier CDC report has identified additional areas, including Arkansas, Kentucky, Missouri, Suffolk County, and New York, as regions with a high prevalence of the condition.
However, recent investigations into two cases of alpha-gal syndrome in women from Washington and Maine published in CDC’s Emerging Infectious Diseases now raise concerns about further spread of the condition. Both women reported tick bites despite never having traveled to areas where the lone star tick typically resides.
The reports reveal that other tick species, including the black-legged or deer tick (Ixodes scapularis) and the western black-legged tick (Ixodes pacificus), may also contribute to triggering the syndrome, although these instances appear to be much rarer.
“US health and public health professionals should be aware of AGS outside the established lone star tick range,” the authors wrote.
“AGS should be considered a potential cause of anaphylactic and allergic reactions in persons with tick exposures, regardless of geographic residence,” they added.
Alpha-gal syndrome can cause a range of uncomfortable to severe symptoms, typically appearing two to six hours after eating red meat like beef, pork, or lamb. From itchy rashes and stomach issues to dizziness and difficulty breathing, the symptoms can be alarming. In some cases, the reaction can be so severe it leads to anaphylaxis, a potentially life-threatening condition.
