According to Vanderbilt University Medical Center, the allergy can cause hives, breathing problems, a drop in blood pressure or even anaphylactic shock after eating red meat or dairy.
The problem has to do with a friendly-sounding sugar called “alpha-gal,” which ticks have but humans don’t. This same sugar is found in red meat, pork and some dairy products, and doesn’t usually bother people when they digest it. But when a tick bite injects it into the bloodstream, the human immune system creates antibodies activated next time the person eats red meat, causing the allergic reaction.
Like other allergic reactions, the condition can be treated with antihistamines and epinephrine.
“This allergy is so weird,” Chris Richey of Millersburg, Mo., told Al Jazeera. “It’s turned my life upside down.” A pot roast landed her in the hospital after she broke out in hives so bad she scratched the skin off her arms.
It’s not just meat victims have to be wary of. Al Jazeera:
Richey has to have her medicine custom made because some pill casings contain gelatin, which comes from cows or pigs. Dairy is also out of the picture for her, since alpha-gal can show up in milk. She knows of another victim who had to cut out her favorite raspberry-filled pastries because the artificial flavoring is made with castoreum, a chemical that comes from the anal scent glands of the North American beaver.
Explaining a sudden aversion to meat can be complicated. “I never thought I’d say this, but I’m starting to feel less Southern,” wrote Jonathan Kime in a 2012 Oxford American essay. Kime struggled to explain he couldn’t eat pork to fellow Southerners after he was bitten by the Lone Star tick. “In a way it’s like saying that if it’s not my own fault, if I didn’t choose to stop eating pork, then fate must be at work, or that God must have done this to me. If you want a North Carolinian to question his faith, tell him God won’t let him eat pork chops.”
The problem was discovered a few years ago, but many still aren’t aware of it, even doctors. “Why would someone think they’re allergic to meat when they’ve been eating it their whole life?” an allergist who saw 200 cases on New York’s Long Island told the Associated Press.
The reaction can take four to six hours to kick in, which is one reason it was so hard to connect the allergy to its cause.
Thomas Platts-Mills of the University of Virginia, an allergy researcher, stumbled on the cause while studying a mysterious sensitivity to a cancer drug in some patients. The drug also contains alpha-gal. He noticed most of the allergic patients came from rural areas in the southeastern United States and also had a meat allergy. The clincher was when Platts-Mills himself was bitten by the tick in 2007 while hiking and wound up with the allergy.
It’s unclear whether people who are bitten will have the allergy for life. “We don’t really know yet how durable this will be” or whether it’s lifelong, like a shellfish allergy, Robert Valet of Vanderbilt University told the Associated Press.
The meat allergy “does not seem to be lifelong, but the caveat is, additional tick bites bring it back,” said Scott Commins of the University of Virginia.
Ticks thrive in humid, woodsy areas where deer, their choice host, live. Lone Star ticks have spread beyond the South in recent decades, as far north as Wisconsin and as far east as Maine as white-tail deer populations have moved and expanded.