A recent study conducted by the Centers for Disease Control and Prevention (CDC) on July 27 has shed light on a red meat allergy associated with tick bites, potentially affecting up to 450,000 individuals.
However, the actual prevalence of this allergy, known as alpha-gal syndrome, may be underestimated, as a concurrent CDC survey revealed that nearly four out of five healthcare providers have little or no knowledge of the condition.
Moreover, only 5 percent of surveyed providers expressed confidence in their ability to diagnose or manage patients with alpha-gal syndrome (AGS).
Scott Commins, MD, PhD, an associate chief of allergy and immunology at the University of North Carolina at Chapel Hill, and the medical director of the UNC Allergy & Immunology Clinic said, “AGS refers to the allergy that can develop following lone star tick bites and causes delayed allergic reactions to beef, pork, lamb, venison, and other forms of mammalian meat and other derived products such as dairy and gelatin.”
Notably, Dr. Commins is the coauthor of both studies.
Is Alpha-Gal Syndrome Common?
Until now, the overall prevalence of alpha-gal syndrome had been unknown. The study reported that over 110,000 individuals have tested positive for alpha-gal, leading to an estimation of approximately 450,000 affected people in the United States alone.
Geographical variations in prevalence exists, with the condition more common in areas where the lone star tick, linked to alpha-gal syndrome, is prevalent. Regions like the mid-Atlantic have reported numerous cases, while areas of high elevation or the West Coast, where the lone star tick is not found, have fewer cases.
The “Unusual” Symptoms of Alpha-Gal Syndrome
AGS exhibits a distinctive characteristic wherein symptoms manifest two to six hours after consuming meat.
Dr. Commins says, “Food allergy traditionally occurs within 5 to 30 minutes after eating the food,” says Commins.
The range of symptoms varies and encompasses nausea, diarrhea, heartburn, indigestion, hives, and even the possibility of anaphylactic shock – a severe, potentially life-threatening allergic reaction.
The report’s authors highlight that healthcare providers are increasingly noting individuals with AGS who experience gastrointestinal symptoms without displaying more conventional or “typical” allergic indicators, such as a rash or swelling.
According to Patricia Lugar, MD, an allergy and immunology specialist at Duke Health in Durham, North Carolina, who diagnoses and treats AGS, another surprising feature of AGS that people with this allergy don’t necessarily react to red meat every time they eat it.
“A person may eat a beef empanada one day — with a small amount of meat — and not have a reaction, but on another day eat a steak followed by a slice of cheesecake and have a very serious reaction that sends them to the emergency room,” she says.
A clinical practice update on AGS for GI doctors was published in April 2023 in Clinical Gastroenterology and Hepatology.
Doctors have Been Skeptical About the Existence of Red Met Allergies for Some Time
Over a decade ago, researchers initially noted a connection between red meat allergies and tick bites as they identified patients who experienced allergic reactions, such as hives or anaphylaxis, subsequent to consuming beef or pork and having been bitten by a tick.
Alpha-gal, a sugar molecule present in most mammals, including cows, lambs, and pigs, is also found in tick saliva. In an information sheet from UNC, Dr. Commins explained that humans do not naturally produce alpha-gal, making it foreign to our bodies.
According to Dr. Commins, “Our immune system can be tricked into making an allergic response to this sugar.” He also explained that once a person is sensitized to alpha-gal, they can get a reaction every time they eat red meat.
As or Dr. Lugar, she shares that for many years, various members of the medical community had a hard time believing that people could be allergic to meat, and moreover, that it could be caused by a tick.
She says, “I understand how, if you’re not originally exposed to these patients, if you’re not managing patients with recurrent sort of mysterious allergic reactions, that it’s very hard to believe that this is what’s going on. It seems quite fantastical.”
Understanding the science behind how this hypersensitivity develops, the disorder’s concentration where ticks are prevalent, and the improvement of symptoms by eliminating exposure to mammals all contribute to making sense of the situation, Dr. Lugar explains.
Causes and Rick Factors of Alpha-Gal Syndrome
The causes and risk factors of Alpha-Gal Syndrome include increased vulnerability for those who experience multiple tick bites (four or more), reside near woodlands, and spend extended periods outdoors in wooded areas, as outline in a paper published in the November 2022 Annals of Allergy, Asthma & Immunology.
Individuals with AGS often exhibit other allergies, according to Dr. Lugar.
A study published in Gastroenterology in January 2021 revealed that among those diagnosed with AGS, 75 percent recalled having been bitten by a tick. The authors noted that the lone star tick can bite in its larval stage when it measures only 0.5 millimeter (mm) to 1 mm in length.
What explains the occurrence of AGS cases in the United States in regions where the lone star tick is not typically found?
Dr. Commins says, “There is some evidence of lone star ticks moving into the Great Lakes area, and the central-western migration of white-tailed deer is likely to expand the range of the ticks.” Additionally, these cases might involve individuals who were bitten while traveling to regions of the country where the tick is prevalent, he notes.
Dr. Commins also shares that other ticks and potentially parasites found outside the United States have also been associated with the allergy.
Diagnosing Alpha-Gal Syndrome Can Be Quite Challenging
Diagnosing Alpha-Gal Syndrome can be challenging. Healthcare providers, particularly allergists, play a crucial role in the diagnostic process. It involves a comprehensive examination of medical history, compatible symptoms, and diagnostic testing using a specific test called lgE to alpha-gal. Dr. Commins emphasizes that this test detects the presence of an allergic antibody directed against the alpha-gal sugar.
Due to the delayed onset of symptoms, occurring three to six hours after food ingestion, patients are frequently informed that they don’t have a food allergy, and the symptoms are often attributed to conditions like irritable bowel syndrome (IBS) or anxiety, according to Dr. Commins.
Treatment options for Alpha-Gal Syndrome are limited. Dr. Lugar asserts that there is no specific treatment other than altering one’s diet. If the diagnostic test yields a positive result, initiating an alpha-gal elimination diet is recommended, leading to the resolution or significant improvement of symptoms.
Alpha-Gal Syndrome Allergy Treatments
Dr. Lugar emphasizes that the sole treatment for AGS involves modifying your diet. Upon receiving a positive diagnostic test result, it is recommended to commence an alpha-gal elimination diet, leading to the resolution or substantial improvement of symptoms.
“The good news is that the allergy can resolve over a period of years if there are no additional bites,” says Dr. Commins.
Reducing the Risk of AGS Through Tick Bite Prevention
Preventing tick bites is crucial for averting tick-borne diseases and lowering the likelihood of developing alpha-gal syndrome, as stated by the CDC.
The CDC notes that the lone star tick is widely distributed throughout the eastern United States, with a higher prevalence in the South. The peak risk of encountering these “very aggressive” tick occurs from early spring through late fall.
Measuring barely a quarter of an inch in diameter, these ticks are so small that you may not feel them on your body or even be aware if you’ve been bitten, according to information from Emory University.
For guidance on avoiding tick bites and handling situations where a tick is found on clothing or the body, the CDC provides the following advice.
- Stay vigilant. While encountering ticks is more common on camping trips of woodland hikes, , individuals often find ticks in their own backyards, especially if residing in grassy, brushy, or wooded areas.
- Safeguard your clothing. Utilize tick repellents with 0.5 percent permethrin on boots, clothing, and camping gear. This protection can endure through multiple wash cycles.
- Use insect repellent. The Environmental Protection Agency (EPA) provides a search tool to assist you in identifying the safest and most effective insect repellent tailored to your needs.
- Inspect your attire, equipment, and pets upon returning indoors. If a tick is discovered on your clothing, remove it and dry your clothes in a high-heat dryer for 10 minutes. If washing is necessary, use hot water to eliminate ticks.
- Conduct a thorough body check. After outdoor activities, inspect your entire body, including underarms, around ears, inside the belly button, behind knees, in hair, between legs, and around the waist.
- Use caution when removing ticks from your body. Instead of using your fingers, follow the CDC’s step-by-step guide on safely removing ticks from your skin, proper disposal, and what to do if you develop a rash or fever within several weeks of tick removal.
In the event that you discover a tick on your body, avoid removing it with your fingers. The CDC provides a comprehensive step-by-step guide outlining the safe procedure for extracting a tick from your skin. The guide also includes instructions on proper disposal of the tick and guidance on actions to take if you experience a rash or fever within a few weeks of tick removal.
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