Just a few months after giving birth to her daughter Rachel last year, Diane Van Eeckhout felt really fatigued. And it wasn't just the baby that was knocking out the 40-year-old Nisswa, Minn., resident.

Her husband had just been diagnosed with lymphoma. And her doctor thought maybe she was depressed, or had fibromyalgia.

But she also had painful stomach cramps. So she tried eating gluten free, then a low-carbohydrate diet. And that's when the rashes started.

"I was literally scratching myself until I was bleeding," she said. "It was on the bottoms of my feet, my palms, inside my ears, my neck. You can't even imagine, it's 24/7, it doesn't go away."

She was treated for eczema. She had her rash biopsied. Still, doctors couldn't figure out what was going on.

Then, in January, her husband heard an MPR News story about a woman in Duluth who had symptoms a lot like hers.

"I looked it up, and I thought, oh my gosh, I was so excited, I finally had what I thought might be an answer."

And it was. She had her blood tested, and she found out she's allergic to a carbohydrate, a sugar, found in red meat that's known as "alpha-gal."

It's a rare allergy that's only been diagnosed for the past seven years or so. It was first identified by a team of researchers at the University of Virginia.

"The original description of 24 patients we felt at the time was really the end of the story," said Dr. Scott Commins, who's now an associate professor of medicine and pediatrics at the University of North Carolina.

"But it turns out that was the beginning of the story, the tip of the iceberg if you will."

Because now they're aware of several thousand cases. Those cases are still concentrated in the southeastern U.S., but they've spread up the East Coast to New England and towards the upper Midwest, as well as to scattered countries throughout the world, in Europe, Australia and now Central and South America.

And that has confounded researchers and doctors. Because initially, the allergy was linked specifically to bites from the lone star tick, which lives primarily in the southeastern United States.

"That explains some of my shock when I first diagnosed it," said Dr. Minto Porter, an allergist at the Essentia Health clinic in Brainerd who treated Diane Van Eeckhout.

There aren't any established populations of lone star ticks in Minnesota, said Elizabeth Schiffman, a senior epidemiologist at the Minnesota Department of Health.

"We'll sometimes find them in the field," she said, "but we don't have nearly the numbers of that species of tick than we do of the black legged tick or the wood tick."

Yet, Porter and other doctors say they're seeing more cases of the alpha-gal allergy.

Porter estimates she's diagnosed about a dozen cases in the past five years.

In Duluth, Essentia Health allergist Alaaddin Kandeel has diagnosed 23 cases. That's five more than in January.

The increase could be because of what's known as a "diagnosis bias" — doctors are simply becoming more familiar with it.

Diagnosing an alpha-gal allergy can be tricky, Porter said, because it doesn't behave like other food allergies, where the reaction occurs almost instantly.

"This one's a little unusual, and it really took the allergy world by storm," she said, "in that patients would develop symptoms six or eight hours after they ingested it."

Dave Neitzel, a state epidemiologist, holds a pair of adult blacklegged ticks collected in the woods at the Rice Creek Park Reserve in Lino Lakes on May 4, 2016. Matthew Hintz for MPR News 2016

Researchers are now pretty convinced the allergy is triggered by ticks other than just lone star ticks, said Scott Commins, including potentially blacklegged, or deer ticks, which have spread across much of Minnesota and are best known for carrying Lyme disease.

"The worldwide data are the main argument for that, because in the places such as Sweden, Europe, and Australia, they don't have the lone star tick, yet they're still seeing patients who are presenting with new cases of this strange meat allergy," he said.

That link to other ticks still hasn't been confirmed. It's also still unclear how long it takes after the tick bite to trigger the allergy.

Dr. Minto Porter in Brainerd sees many patients who are "snowbirds" who spend their winters in the southern U.S. So it's possible they could have been bitten by a lone star tick there.

And there are other key, unanswered questions, Commins said, that he and others continue to research. For example, what exactly in the tick bite triggers the allergy? And why do some people get it, but thousands of others who are bitten by ticks, don't?

"We're concerned that maybe we're sitting on the verge of something that really begins to affect a large percentage of the outdoorsy population in certain areas," Commins said.

Eeckhout still ventures outside with her family. They planted a big garden this year in the woods where they live on a small lake.

She decided to speak out about what happened to her because she's convinced there are other people suffering, who don't know why, and that maybe sharing her story can help.

"I just really hope someone can get some help, or create awareness out there, in case people are sick."

She's feeling much better now, and has adjusted to a red meat-free diet, although she still finds many people still don't believe a tick and an allergy are to blame.

"They look at you like you're insane," she said. "They're like yeah, right, no one's allergic to meat!"