Tick bites could cause an allergy to red meat, CDC says

Lone star tick warning sign.
(Image credit: wildpixel / Getty Images)

Steak lovers, beware: Ticks could be giving people an allergy to red meat.

The condition is known as alpha-gal syndrome (AGS) and can come from the bite of a lone star tick. The Centers for Disease Control and Prevention estimates that approximately 450,000 people in the United States might be living with AGS.

AGS is a condition "caused by an immune reaction to the sugar alpha-gal," which is "found in the flesh of most non-primate mammals," according to Scientific American. The tick bite causes the sugar to pass through a person's skin, "which has its own immune sentries waiting to pounce on foreign invaders," per CNN. The exposure "appears to put the body on high alert for this sugar, which is found in non-primate mammals and in products made from them." Those with the condition need to avoid red meat and any products that come from such animals, which include some makeup and gel capsules.

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The severity of the condition can vary and may cause "hives, nausea, diarrhea or anaphylactic shock," The New York Times reported, adding that "even patients who have the syndrome may not feel sick every time they eat meat." The allergy is "consistently inconsistent," Dr. Johanna Salzer, a disease ecologist and veterinarian at the CDC, told the Times. "So this makes it a real challenge for health care providers."

In addition, the condition is not widely known. A CDC study, in which Salazar was involved, found that of 1,500 surveyed doctors and nurse practitioners, "42% were not aware of AGS, and another 35% were not confident in their ability to diagnose or manage AGS patients." Meanwhile, the disease is on the rise, from about 13,000 patients in 2017 to nearly 19,000 in 2021. This number reflects just those who were tested so there are likely more undocumented cases, per the Times.

There is currently no cure for the condition but it can be managed. Some have been able to add red meat back into their diets over time. "Alpha-gal syndrome can be a lifelong condition," Salzer said. "It definitely needs to be a part of the conversation of why tick prevention is so important for public health."

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Devika Rao

Devika Rao is a staff writer for The Week. She graduated from Cornell University with a degree in Environment and Sustainability and a minor in Climate Change. Previously, she worked as a Policy and Advocacy associate in the nonprofit space advocating for environmental action from the business perspective. She is passionate about the environment, books, and music.