Allergic to Meat: Lone Star Tick May Make Vegetarians of Some
Tick bite may trigger allergic reaction to red meat, researchers say.
June 20, 2012— -- There's a new weapon in the war on meat: a tiny tick, whose bite might be spreading meat allergies up the East Coast.
A bite from the lone star tick, so-called for the white spot on its back, looks innocent enough. But University of Virginia researchers say saliva that sneaks into the tiny wound may trigger an allergic reaction to meat -- agonizing enough to convert lifelong carnivores into wary vegetarians.
"People will eat beef and then anywhere from three to six hours later start having a reaction; anything from hives to full-blown anaphylactic shock," said Dr. Scott Commins, assistant professor of medicine at the University of Virginia in Charlottesville. "And most people want to avoid having the reaction, so they try to stay away from the food that triggers it."
Commins said cases of the bizarre allergy are popping up along the East Coast and into the Bible Belt, areas ripe with lone star ticks. He's already seen 400 or so. And 90 percent of them have a history of tick bites, he said.
"It's hard to prove," he said of the link between lone star ticks and meat allergies. "We're still searching for the mechanism."
Allergies are immune reactions to foreign substances, from pet hair to peanuts. As antibodies attack the substance that caused the reaction, they trigger the release of histamine, a chemical that causes hives and, in severe cases, life-threatening anaphylaxis.
Commins said blood levels of antibodies for alpha-gal, a sugar found in red meat, lamb and pork, rise after a single bite from the lone star tick. He said he hopes experiments that combine tiny samples of tick saliva with the invisible antibodies will prove the two are directly connected.
"It's complicated, no doubt," said Commins. "But we think it's something in the saliva."
Experts say the six-hour lag between exposure to meat and the allergic reaction complicates things even more.
"It's very atypical as food allergies go," said Dr. Stanley Fineman, president of the American College of Allergy, Asthma and Immunology. "Most food allergies occur very quickly. And it's also a bit unusual to see adults develop a food allergy."
But the tick bite theory could help explain the sudden onset of some meat allergies, Fineman added.
Other Common food allergens include peanuts, shellfish, milk, eggs, soy and wheat. And most food allergy sufferers are glad to discover the source of their misery, even if it means upheaval for their diets.
"Avoidance is the best way to handle any food allergy," he said.
But meat allergies are hard for some brawny barbecuers to swallow.
"Some people are totally destroyed," said Commins. "Others say, 'Maybe I'm better off without it.'"