Rising Risk of Red Meat Allergy Linked to Tick Bites: New CDC Findings Reveal Concern for Americans
New data from the CDC reveals that alpha-gal syndrome—a tick-borne allergy to red meat—may be more prevalent than previously understood. While scientists once believed that only the lone star tick was responsible for this condition, recent studies indicate that blacklegged (deer) ticks might also play a role. It’s essential to take precautions against tick bites and consider AGS if you experience unexplained allergic reactions.
Alpha-gal syndrome (AGS) is an allergic condition to red meat caused by tick bites. This condition is becoming increasingly recognized in the United States, and new findings suggest that multiple tick species can trigger it.
Traditionally, health experts identified the lone star tick (Amblyomma americanum), common in the Eastern, Southeastern, and South-Central regions of the U.S., as the primary cause of AGS. However, recent research from the Centers for Disease Control and Prevention (CDC) shows that individuals developing AGS after bites from blacklegged ticks, also known as deer ticks, raises new concerns.
Recent estimates indicate that approximately 450,000 Americans have been affected by AGS from 2010 to 2022. “These findings broaden our understanding of where alpha-gal syndrome may occur and who’s at risk, which could improve diagnosis and increase awareness among healthcare providers in regions previously thought to be low-risk, such as Maine,” stated Bobbi Pritt, MD, from the Mayo Clinic, highlighting the need for increased vigilance.
What Is Alpha-Gal Syndrome?
Alpha-gal syndrome occurs when a tick bites an individual and introduces alpha-gal—a carbohydrate present in all non-primate mammals—into the bloodstream. According to Ryan Steele, DO, a Yale Medicine allergist-immunologist, this triggers the immune system to produce antibodies called immunoglobulin E (IgE).
Upon subsequent exposure to the alpha-gal carbohydrate, these IgE antibodies can initiate allergic reactions, which may include:
- Hives
- Stomach pain
- Drop in blood pressure
- Anaphylaxis (in severe cases)
It’s important to note that reactions often manifest two to six hours after consuming red meat or mammal-derived products, including gelatin and dairy.
When individuals eat red meat, such as beef, pork, venison, or lamb, their immune system identifies the alpha-gal and overreacts. A diagnosis involves a history of tick bites coupled with a positive blood test for IgE antibodies. Interestingly, some individuals may find that their IgE levels decrease over time, allowing them to consume meat and dairy again, though repeated tick bites can reactivate the allergic response.
Case Studies: Alpha-Gal Syndrome from Blacklegged Ticks
Two significant CDC case studies shed light on AGS cases stemming from blacklegged ticks. The first case involved a 61-year-old woman from Oregon who sought medical attention in spring 2017 after exhibiting severe allergic reactions like skin rashes, itchiness, and throat tightness. A tick was discovered on her shoulder after a walk in the woods.
Following her allergenic symptoms post-consumption of red meat, she was diagnosed with AGS. Notably, she experienced increased IgE antibody levels after being bitten by Ixodes pacificus ticks (western blacklegged ticks) in April 2020 and March 2022, demonstrating that these ticks can also trigger AGS.
The second case examined a 45-year-old woman in Maine who noticed a tick attached to her leg after a hike in May 2022. Her subsequent allergic reactions to red meat confirmed an abnormal rise in IgE levels, prompting her to avoid certain meats and some dairy products. Over time, her IgE levels decreased, allowing her to reintroduce meat into her diet.
“These case reports highlight that patients in areas outside the established range of the lone star tick may also be at risk,” noted Johanna Salzer, DVM, PhD, indicating the need for increased awareness of AGS.
Expanding Understanding of AGS
These findings indicate that various blacklegged tick species across the U.S. could cause AGS, suggesting that more Americans should be aware of the symptoms. Salzer emphasizes, “AGS is primarily caused by the bites of lone star ticks, but it is possible that other ticks in the U.S. play a role in causing AGS in some people.”
Regions previously considered low-risk for AGS, such as Maine and Oregon, may now exhibit greater exposure to tick species that can induce AGS.
Protecting Yourself Against AGS and Tick Bites
Despite ongoing research, much remains unknown about AGS, including the reasons for the predominance of lone star ticks in causing the majority of cases. The primary and best-supported cause remains tick bites.
To effectively minimize the risk of AGS, consider taking the following precautions:
- Use EPA-recommended bug repellents.
- Wear clothing treated with permethrin.
- Check yourself and your pets for ticks after outdoor activities.
Checking pets is critical, as they can bring ticks into the home and spread tick-borne diseases like Lyme disease. Health professionals urge individuals living in areas with lone star, blacklegged, and western blacklegged ticks to be vigilant for symptoms of AGS, especially when encountering unexplained allergic reactions to meats or dairy products.
In summary, enhanced awareness of AGS and precautionary measures can prove vital in protecting yourself and your community from this increasingly recognized allergic condition.
