Ticks that cause a life-threatening red meat allergy are spreading. Know these signs

This summer, be especially vigilant about a tiny menace that could spoil your appetite for years.

A bite from the lone star tick — “a very aggressive tick that bites humans,” as the Centers for Disease Control and Prevention describes it — can lead people to develop an allergy to red meat and, in some cases, dairy.

Experts who have been monitoring the strange and potentially life-threatening sensitivity, known as alpha-gal syndrome, say the number of people affected just keeps rising. New data from the CDC released in July 2023 indicate that as many as 450,000 people have developed the condition since 2010 — but few clinicians are familiar with alpha-gal syndrome and even fewer know how to diagnose it.

Dr. Ann Carpenter, lead author of one of the new CDC papers, called alpha-gal syndrome “an emerging public health problem, with potentially severe health impacts that can last a lifetime for some patients” in a statement.

Alpha-gal syndrome on the rise

One of the July 2023 CDC reports estimated that, from 2017 to 2022, there were more than 90,000 documented cases of suspected alpha-gal syndrome in the U.S. But because diagnosis requires a test and exam, and many never get tested, the number of people who’ve developed the condition since 2010 is likely closer to 450,00.

The report estimated that cases of alpha-gal syndrome increased by 15,000 per year from 2017 to 2021 and found that cases were most common in areas where the lone star tick is known to live, such as Arkansas, Kentucky, Missouri, and Suffolk County, New York.

The CDC called the increase in the number of cases of alpha-gal syndrome since 2010 “substantial.” But despite this uptick, nearly half of clinicians have never heard of it, and less than a third of those who have know how to diagnose it, a new CDC report found.

Allergist Dr. Erin McGintee, who practices on Long Island, New York, told NBC News that she’s seen the number of her patients with alpha-gal syndrome increase over the past decade. She estimates she’s seen 900 people with it.

“Out here in the Hamptons, most people know at least one other person who has the syndrome,” she said.

A new map corresponding with the new CDC report illustrates that alpha-gal syndrome cases are highly concentrated in the Southeast (as well as Long Island).

A July 2023 map from the CDC shows where in the U.S. alpha-gal syndrome is most diagnosed. The condition is spread through the bite of a lone star tick.  (CDC)
A July 2023 map from the CDC shows where in the U.S. alpha-gal syndrome is most diagnosed. The condition is spread through the bite of a lone star tick. (CDC)

Previous research aligns with the July 2023 CDC data.

A 2018 study in Oxford Medical Case reports warned the prevalence of alpha gal syndrome, has been “drastically” increasing. And according to a 2021 study in the Annals of Allergy, Asthma and Immunology, there were over 34,000 reported causes in the uses from 2010 to 2018. The authors called alpha-gal syndrome “an increasingly recognized public health problem.” It pointed to Arkansas, Virginia, Kentucky, Oklahoma and Missouri as having the highest number of positive cases per 100,000 people.

The rising numbers of alpha-gal syndrome worry Dr. Scott Commins, an allergist and associate professor at the University of North Carolina at Chapel Hill School of Medicine.

“It does seem like it’s really growing,” Commins, who was one of the first doctors to study alpha-gal syndrome, told TODAY.com.

“It appears the range of this tick is expanding. … The other aspect of this that we’ve noted during the pandemic is that folks are getting outside — which is great — and hiking, going to national parks, trails, and this activity has led to increases in tick bites overall.”

Lone star tick territory grows

It’s part of an overall trend. The number of reported tickborne diseases more than doubled from 2004 through 2016, the CDC reported in 2018. During that period, seven new germs that spread through tick bites were discovered in the U.S.

Health departments reported a record number of cases of tickborne disease to the CDC in 2017. The number declined somewhat in 2019, the last year for which statistics were available, but was still the second-highest in recent years.

The lone star tick is widespread in the southeastern and eastern U.S., and is now being found as far north as MaineWisconsin  and Canada. A crowdsourced map is keeping track of alpha-gal allergy cases worldwide.

A 2020 report prepared for the government’s Tick-Borne Disease Working Group said the geographic distribution of lone star ticks is “expanding.”

One reason may be the explosion of the deer population on the East coast, said Dr. Thomas Platts-Mills, who heads the division of allergy and clinical immunology at the University of Virginia and who helped discover the link between the lone star tick and the allergy.

A deer can carry 500 ticks — primarily lone star ticks, he said.

“This is a very odd situation. Most ticks are specific for some animal, so there are dog ticks, pig ticks, cattle ticks — these ticks really don’t like humans much. But the lone star tick really does like humans,” Platts-Mills said. “We’ve got deer on the lawns, and they’re dropping these ticks everywhere.”

What is alpha-gal syndrome?

The alpha-gal allergy is named after a sugar found in animals. Humans don’t have alpha-gal, but make an immune response to it. As TODAY.com first reported in 2016, it’s believed the lone star tick picks up alpha-gal after biting a deer, then transfers it into a person’s bloodstream when it bites a human. When a person is sensitized to alpha-gal, it triggers an allergic reaction. A blood test can confirm the allergy.

Researchers have linked this sensitivity to the buildup of plaque in heart arteries, boosting the risk of heart attacks and stroke for people who have the allergy.

Platts-Mills has the allergy himself: He was bitten in August 2007 and experienced his first reaction that November hours after eating lamb chops. The delayed response can make it a challenge for doctors and patients to connect the foods with symptoms, the American College of Allergy, Asthma & Immunology noted.

“One of the fascinating things, the hallmark of this, is that the symptoms occur in a delayed fashion, three to six hours after someone typically eats red meat,” Commins said.

Symptoms of alpha-gal syndrome

According to Commins, alpha-gal syndrome symptoms can include:

People can end up with anaphylaxis, a life-threatening allergic reaction that requires emergency treatment. Most of Commins’ patients carry Epi pens.

The allergy involves red meat like beef, pork or lamb; and, in some cases, dairy — especially heavy-fat dairy like ice cream. Doctors aren’t sure whether it only takes one lone star tick bite or several for people to develop the sensitivity, but anyone, including children, can develop it, Commins said.

Alpha-gal syndrome treatment

The treatment is avoidance, so patients are limited to eating meat from fish, chicken and turkey.

“If it swims or flies, it’s fine,” Commins said.

“If you’re my age, you’ve got a cardiologist who’s been telling you the treatment already, and that is avoid red meat completely, and don’t eat full-fat milk and cheese,” said Platts-Mills.

The allergy usually goes away after two to three years as long as the patient has no additional tick bites. Doctors are working on a vaccine, but that’s likely several years away.

To avoid tick bites, experts offer these suggestions:

  • Stick to marked trails and walk in their center. Ticks live in grassy, brushy or wooded areas, so you want to avoid brushing up against thick vegetation.

  • Use tick repellents.

  • Perform tick checks on your clothes and body after you’ve been outside. When it comes to lone star ticks, the adult female has a white dot on her back.

  • Shower within two hours of coming indoors.

  • If you get a tick bite, remove the tick and monitor yourself for any symptoms.

  • If you notice any concerning symptoms after eating red meat, get the alpha-gal allergy blood test.

This article was originally published on TODAY.com