Signs of a rare allergy to red meat, which can begin when a person is bitten by a certain tick species, are being detected in people beyond the southeastern U.S. where the ticks reside, according to new research.
The red meat allergy was first described in 2008, and it causes symptoms that can include hives, skin rashes, indigestion, and in extreme cases, anaphylaxis, a state of whole-body inflammation that is potentially deadly.
"What was surprising is the fact that there was so many positive patients outside the southeastern United States," said study researcher Michelle Altrich, clinical laboratory director at ViraCor-IBT Laboratories. The research was presented today (Nov. 9) at the annual American College of Allergy, Asthma and Immunology conference in Anaheim, Calif. The study was funded by the company, and has not been published in a peer-reviewed journal.
The researchers examined three years' of tests for the allergy from hundreds of people across the United States.
The results showed that people living in regions where lone star ticks are found were 32 percent more likely to have antibodies of a type called "alpha-gal IgE," which are involved in the allergy. These antibodies bind to a sugar found in meat, and their presence in the blood means the person has had some type of reaction to meat, with symptoms ranging from very mild to life-threatening, Altrich said.
But in regions free of lone star ticks, rates of positive test results were unexpectedly high, researchers found. Across the western coastal states, and in Idaho and Nevada, 23 percent of residents tested positive for the alpha-gal sugar, indicative of a meat allergy. Researchers found a similar percentage of people testing positive in the north-central part of the country, including the Dakotas, Nebraska, Minnesota, Iowa, Wisconsin, Illinois and Michigan, but only 4 percent of residents from Montana, Wyoming, Utah, Colorado, Arizona and New Mexicotested positive.
While it's unclear why people who don't live in lone star tick-infested regions test positive for the antibodies, it could be that other ticks, such as the blacklegged or western blacklegged ticks, also trigger the reaction. It could also be due to people traveling, or a yet-undiscovered reason, Altrich said.
Stanley Fineman, president of the American College of Allergy, Asthma and Immunology, said that he has been seeing an increasing number of patients with allergies to red meat at his Georgia practice.
"Several years ago, it wasn't really on our radar screen. Now that it is on the screen, we're seeing patients with it. It's the kind of syndrome that unless you're looking for it, you can miss it," said Fineman, who was not involved with the study and has no links to the company.
The allergic response could worsen with continued exposure to meat, which makes awareness particularly important, Fineman told MyHealthNewsDaily. The allergy is unusual because it involves a type of sugar in meat, whereas most food allergies involve proteins. Symptoms occur three to six hours after eating meat, unlike the immediate symptoms typical of most food allergies.
Fineman said that if people notice unexpected rashes or allergic responses, they should think about what they ate in the last few hours.
"If they ate any meat, they should probably see an allergist to figure out if they have this condition," he said.
Altrich said future research will examine other what factors may be important in meat allergies, such as people's age or gender.
"The main take-home is that this allergy can be found outside the Southeast, so patients and their physicians have to be aware of that," Altrich said.
Pass it on: Be aware of rashes, hives hours after you eat red meat; it might indicate an allergy.