A red meat allergy is on the rise in the St. Louis region as tick season becomes longer and hotter in the Midwest.
Doctors say more people in the area are being diagnosed with “alpha-gal” syndrome, which can cause a severe allergic reaction to red meat.
The syndrome appears to be common in those who have had tick bites, although researchers are still studying exactly what causes the allergy, said Dr. Maya Jerath, an allergist and immunologist at Washington University and Barnes-Jewish Hospital. Some people, after being bit by a tick, report a sudden aversion to meat from cows, pigs and other mammals.
“The number of patients we're diagnosing is going up,” Jerath said. “The number of ticks is increasing, potentially due to hotter summers, longer summers. But then also the range of this lone star tick is moving west and north. So it's actually expanding.”
The map of incidence of the syndrome throughout the United States matches up almost perfectly with the map of the lone star tick’s range, in the Southeastern and Midwestern parts of the country, she said.
Alpha Gal is short for alpha galactose, a sugar found in red meat but not in humans, reptiles, birds or fish. A person is bit by a tick and then reports an allergic reaction that shows up a few hours after eating red meat, Jerath said.
Not all people bit by a tick develop alpha gal syndrome, she said. And there’s even some evidence that other creatures like chiggers can also trigger the allergy.
Jerath hypothesizes that the allergic reaction is triggered through exposure to the sugar through the skin. That’s why people can eat meat containing the alpha gal sugar and not have a reaction.
“When you see antigens [introduced] through your skin, that is a place where your immune system is on heightened alert, to react to it,” she said.
In some patients, that reaction is severe, and it can range from indigestion to anaphylactic shock, she said.
About six years ago, St. Louisan Andy Heaslet noticed he started getting nauseated after eating burgers and other kinds of meat.
“You know, living in St. Louis, we're a good barbecue town,” he said. “I would notice I was uncomfortable after making my own barbecue. But I just assumed that was from drinking too much!”
Heaslet, who works at the Sierra Club and regularly ventures outdoors, finally figured out what was causing the allergy after he heard a segment about alpha gal on the science program Radiolab and went to see a doctor.
Now he steers clear of most meat, he said. It makes him develop a fever, itch all over and have trouble breathing.
“It's sort of like all the telltale signs of an allergic reaction,” he said. “Just my body is like, ‘Something bad is in you! Get it out!’”
Alpha gal is just one tick-related illness that’s seeing an increase as tick habitats become more widespread. Missouri researchers have found the tick season is getting longer, wetter and hotter and different species — including the lone star tick — are moving farther north from their historic habitats in the Southeast.
There’s no treatment for the syndrome other than avoiding red meat, doctors say.
The best way to steer clear of alpha gal syndrome is by avoiding tick bites in the first place, Jerath said. That means wearing long pants and sleeves in the woods, showering right after nature excursions and doing regular tick checks after outdoor adventures.
Correction: A previous version of this story misspelled Dr. Maya Jerath's last name.
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