Thousands of people are now allergic to meat because of tick bites. An expert says 'this is just the tip of the iceberg.'

• Alpha-gal syndrome is a serious allergy to red meat caused by the lone star tick.
• In 2009 there were 24 cases of alpha-gal syndrome, now the CDC reports that there are over 110,000 cases.

Spending time outdoors may be great for your health, but for some people it can lead to a rare health condition: An allergy to red meat. The cause is the lone star tick; one-quarter of an inch in length, one bite from this tick can result in an red meat allergy to red meat — and sometimes meat byproducts like dairy — that lasts for years. And a new report from the Centers for Disease Control published today found that the number of people affected is skyrocketing.

One bite could make you allergic to meat

Lone star ticks roam throughout the eastern half of the United States, from Florida all the way up to Maine. Lone star ticks lust for blood, and when they bite human subjects they sometimes inject alpha-gal, a sugar also found in meat, into the bloodstream of their prey. For some people, this revs up their immune system and can lead to an allergic reaction when they subsequently eat meat or products that contain alpha-gal.

Some common symptoms of the tick-borne allergy, called alpha-gal syndrome, are a tight neck and shoulders, erratic heartbeat and trouble breathing after eating meat. Other symptoms include extreme nausea, diarrhea and vomiting after eating meat.

Additionally, many people experience an extremely itchy and red spot where they received the tick bite, said Dr. Scott Commins, a doctor at the University of North Carolina and co-author of the recent CDC report.

What's also strange, Commins said, is that there's a delay between eating meat and experiencing symptoms. Someone could eat a burger for dinner at say, 8pm, and not experience an upset stomach until 8am the following morning.

The condition doesn't just affect meat-eaters — even vegans and vegetarians can be affected as well. "Products from or ingredients from these animals are used in so much of our daily lives, like medications and vaccinations, surgical grafts gelatin that may be in like gummies it's very different than just, like, don't eat red meat," Commins told Insider.

There's no cure for alpha-gal syndrome, but it often resolves in 3 to 5 years — pending that no additional tick bites from lone star ticks occur. Management for alpha-gal syndrome is similar to other severe allergies, and includes avoiding affected foods, and carrying an Epipen. Some scientists have even started sending lab-made bacon to people with the allergy, Insider previously reported.

Once rare, alpha-gal syndrome is on the rise

In 2009, only two dozen cases of alpha-gal syndrome were identified, but by 2018 that number had risen to 34,000 cases. In the new CDC report, experts found that number has now more than tripled — and they estimate that as many as 450,000 people may have been affected since 2010.

"I'm seeing eight to 10 new patients a week still, and these these are people who have had reactions and developed it all within the past couple of years, if not couple of months," Commins said.

The rise is "absolutely concerning" to researchers and doctors, said Commins, who notes that these numbers are "just the tip of the iceberg." These numbers only represent the number of people who have been tested, he said; there are many more who probably haven't been tested and just stopped eating meat because it made them feel bad.

Alpha-gal syndrome is still relatively unheard of, so part of the rise in cases could be because people are more aware of the allergy. Additionally, the lone star tick's range is increasing due to warmer temperatures as a result of climate change.

Stay safe from ticks

The effects of the condition can be distressing, Commins said, because unlike a peanut allergy developed as a child, where someone didn't know the taste and doesn't miss it, alpha-gal syndrome often affects people who really like meat.

"I even had a patient who said he feels less southern because he can't eat barbecue," Commins said.

Although there is no cure from alpha-gal syndrome, general tick precautions can help prevent tick bites altogether.

The CDC recommends avoiding grassy, brushy and wooded areas where ticks can be found, wearing clothing treated with permethrin, and using Environmental Protection Agency registered insect repellents. Additionally, you should always check your clothing for ticks and perform a thorough tick-check after coming in from the outdoors. If you have pets, check them as well after they return from the outdoors, because pets can bring ticks into the house and onto you.