Q&A: Spring has sprung — and so has prevalence of alpha-gal, other tick-borne illnesses

Key takeaways:

• Cases of alpha-gal syndrome are being found outside of the original region of concern.
• Health care provider unawareness is an obstacle to diagnosis.
• There is no drug for treating this allergy.

With spring underway, the likelihood of getting a tick-borne illness is elevated, according to Mayo Clinic. One that clinicians should be on the watch for is alpha-gal syndrome, a food allergy contracted mainly from Lone Star ticks.

According to the CDC, patients who have alpha-gal syndrome (AGS) will show symptoms following red meat consumption or exposure to products created from mammals, including gelatin, glycerin, magnesium stearate and bovine extract.

“AGS is different from most food allergies because the person becomes allergic to a sugar, galactose-alpha-1,3-galactose, not a protein, which is the most common issue,” Douglas H. Jones, MD, said in Healio’s Food Allergy: Fact vs. Fiction column. “This alpha-gal sugar is present in the meat of most mammals but not humans, birds, fish or apes.”

To learn more about common triggers of AGS, changes in Lone Star tick migration over the years and recent developments in AGS testing and treatment, Healio spoke with Gary Falcetano, PA-C, AE-C, scientific affairs manager for allergy at Thermo Fisher Scientific.

Healio: How are seasonal/migration patterns for Lone Star ticks changing? Are there regions of the country that should be more concerned now?

Falcetano: Both Lone Star ticks and their mammalian hosts have continually expanding geographic ranges. Deer, which are the primary hosts for adult ticks, have migration patterns that place them in proximity to increasing numbers of humans who are then at risk for exposure to the ticks whose range has expanded along with their hosts. In addition, we are now seeing evidence that the alpha-gal molecule, which is transmitted by tick bites, may be transmitted by species of ticks in addition to the previously identified Lone Star tick (Amblyomma americanum).

While AGS was originally thought to be only a concern in the Southeastern U.S., we now are seeing cases up and down the East coast and into the Central U.S. as well. There have been pockets of patients as far North and West as Northern Minnesota and even hot spots on Long Island New York and Martha’s Vineyard in Massachusetts. Recent reports have even linked cases in Maine and Washington State with blacklegged ticks (Ixodes scapularis in Maine and Ixodes pacificus in Washington State).

Healio: What are the most common triggers for AGS?

Falcetano: Common food triggers of AGS are red (mammalian) meats including beef, lamb, pork, venison and really any meat from a mammalian source. Organ meats and fattier cuts of meats seem to carry increased risks for causing a reaction. Mammalian milk also contains lesser amounts of alpha-gal and may be a trigger for some AGS patients. Gelatin products including gummy bears may be triggers for some patients that react to even small amounts of alpha-gal. Co-factors such as alcohol and exercise can also cause patients with an alpha-gal sensitization to react when consuming mammalian meat-containing products in conjunction with ingestion of alcohol or in close association with exercise. These co-factors seem to enhance the immune system’s reactivity.

Certain medications and vaccines contain varying amounts of alpha-gal. Animal-derived medical products, such as heart valves from pigs or cows, monoclonal antibodies, heparin and certain antivenoms may contain alpha-gal. As with any potentially severe allergy, patients with AGS should work with their health care providers to make decisions about individual risk and benefit from specific foods, vaccines and medications.

Healio: What are the biggest obstacles in diagnosis?

Falcetano: There are three major obstacles to the diagnosis of AGS.

The first obstacle is the relative unawareness of health care providers of this unusual allergy and how patients may present. In a recent survey of providers across the U.S., 42% were unaware of AGS.

Second, an additional 35% were not confident in their ability to diagnose and manage AGS patients. Among all respondents who were aware of AGS, 48% reported that they did not know the correct diagnostic tests to order.

The third obstacle is the unusual presentation of AGS symptoms because AGS symptoms from food ingestion are often delayed from 3 to 6 hours or sometimes even longer. This does not present like a typical food allergy where symptoms present rapidly within the first 2 hours after ingestion.

Healio: Are there any recent developments in testing that readers might not be familiar with that you would like to spotlight?

Falcetano: There is a specific IgE test for alpha-gal that has been FDA cleared and available at national and regional clinical laboratories since 2020. It is important for providers to know that this test is accessible to anyone who normally orders laboratory testing, and the methodology is not different from the ImmunoCAP (Thermo Fisher Scientific) testing that they may already be ordering for environmental, food or venom allergens. Clinicians can visit Thermo Fisher Scientific’s Allergen Encyclopedia for more information.

Healio: Are there any recent developments in treatment that readers might not be familiar with that you would like to spotlight?

Falcetano: Currently, the only treatment for AGS is avoidance of alpha-gal-containing foods and other products such as medications and vaccines. The most important thing patients can do is avoid further tick bites. Experience has shown that without further tick bites, patients’ levels of IgE sensitization decrease, and many patients can resume an unrestricted diet once that occurs. Close collaboration with a clinician experienced with AGS is essential.

Healio: How can allergists work with other specialties, such as gastroenterology, to improve care?

Falcetano: The American Gastroenterological Association has recently issued a clinical practice update that provides direction for gastroenterology clinicians that they should be aware of the diagnosis and management of AGS because a subset of alpha-gal allergic patients exhibits gastrointestinal (GI) symptoms such as abdominal pain, diarrhea, nausea or vomiting without skin changes or anaphylaxis.

The diagnosis of AGS can be made among patients with GI distress and increased serum alpha-gal IgE antibodies whose symptoms are relieved adequately on an alpha-gal avoidance diet that eliminates pork, beef and mammalian-derived products. Patients who also have reactions such as facial swelling, urticaria and respiratory difficulty should be referred to allergists. GI AGS recently was described, and prospective studies are needed to better understand this condition.

Although there are areas of the country where AGS is rare, all clinicians should maintain a high index of suspicion when patients present with symptoms consistent with alpha-gal sensitization. With a highly mobile population that may be visiting areas where alpha-gal is prevalent and the new realization that additional ticks may be vectors for this syndrome, all clinicians, regardless of their geographic location, should keep AGS on their list of differential diagnoses when seeing patients with unexplained symptoms of urticaria, pruritus, abdominal pain, nausea, vomiting and any other allergy-like symptoms without a clear explanation.

For more information:

Gary Falcetano, PA-C, AE-C, can be reached at gary.falcetano@thermofisher.com.

References:

• CDC. About alpha-gal syndrome. https://www.cdc.gov/alpha-gal-syndrome/about/?CDC_AAref_Val=https://www.cdc.gov/ticks/alpha-gal/index.html. Published May 15, 2024. Accessed April 21, 2025.
• CDC. Products that may contain alpha-gal. https://www.cdc.gov/alpha-gal-syndrome/products-that-contain-alpha-gal/index.html. Published May 14, 2024. Accessed April 21, 2025.
• Concern over Lone Star tick as tick season begins. https://newsnetwork.mayoclinic.org/discussion/concern-over-lone-star-tick-as-tick-season-begins/. Published March 22, 2022. Accessed April 21, 2025.