A potentially life-threatening allergy triggered by tick bites may affect as many as 450,000 people in the US, according to the Centers for Disease Control and Prevention (CDC).
The condition, known as alpha-gal syndrome (AGS), develops when a person becomes sensitized to alpha-gal, a sugar molecule found in most mammals but not in humans. The molecule can be transmitted through the saliva of certain tick species during a bite.
According to the CDC, more than 110,000 suspected cases of AGS were identified between 2010 and 2022. Because the condition is not nationally reportable, health officials say the true number of cases is unknown and could be significantly higher.
People with AGS can develop allergic reactions after consuming red meat or other mammal-derived products, leading to symptoms that range from mild discomfort to severe, potentially life-threatening reactions.
The CDC said the syndrome is most commonly associated with bites from lone star ticks in the US, although blacklegged ticks and western blacklegged ticks have also been linked to cases. Most reported infections have occurred in southern, eastern and central states where lone star ticks are prevalent.
Health officials said AGS can affect people of all ages, though most reported cases have involved adults.
Diagnosis typically involves a physical examination, a review of patient history and blood tests that detect antibodies to alpha-gal. Some patients may also undergo allergy skin testing.
There is currently no cure for AGS. Medical experts recommend that affected individuals avoid mammalian meat products such as beef, pork, lamb and venison, while some patients may also need to eliminate dairy products and certain medications containing alpha-gal.
The CDC said preventing tick bites remains the most effective way to reduce the risk of developing the condition.
Alpha-gal syndrome was first recognized in the early 2000s after researchers identified a link between tick bites and delayed allergic reactions to red meat. Awareness of the condition has increased in recent years as reported cases have expanded across parts of the United States.
