Have you ever eaten steak at dinnertime and then developed hives at midnight?
As tick season kicks into gear, it’s a good idea to know about a potentially life-threatening food allergy called alpha-gal syndrome that may occur after certain tick bites – especially the lone star tick, according to the Centers for Disease Control and Prevention (CDC).
“An allergy to ‘alpha-gal’ refers to having a severe and potentially life-threatening allergy to a carbohydrate molecule called galactose-alpha-1,3-galactose that is found in most mammalian or ‘red meat,’” according to the American Academy of Allergy Asthma & Immunology.
The lone star tick, named for its characteristic white star shape on its back that some suggest is shaped like Texas and commonly found in the South, first picks up the alpha-gal molecule from mammalian animals that they commonly bite, like cows and sheep, then transfers it to humans after a bite, according to the Mayo Clinic.
Anyone bitten by the tick, especially multiple times, becomes “sensitized” where the immune system produces antibodies against alpha-gal, so allergic reactions can occur not only when re-exposed to mammalian meat, but also future bites and even medications that contain alpha-gal, per American Academy of Allergy Asthma & Immunology.
“It all started with the cancer drug cetuximab. The year it was released, it became obvious that some patients were having bad reactions to it in Virginia, North Carolina, Tennessee, Arkansas, southern Missouri and eastern Oklahoma,” said Dr. Thomas Platts-Mills, who made the original discovery of the meat allergy.
He proved if patients had the type of antibody that is well known to be related to allergies, known as IgE, to the cancer drug before taking it, they were 30 times more likely to have an allergic reaction to it. He also discovered with his team that these antibodies were binding to alpha-gal in patients who suffered delayed allergic reactions to red meat, according to a 2017 news release.
He was working with Jake Hosen, a specialist-doctor in training at the time known as a fellow, who spent two days researching other diseases that fit “…the same geographic pattern as the alpha-gal allergy and the only one that matched was Rocky Mountain spotted fever, and we know that is spread by Lone Star ticks,” said Platts-Mills, professor of medicine and microbiology at University of Virginia.
“That’s when we started asking patients if they noticed the allergies beginning after they received tick bites.”
So this is why some people who are bitten by ticks can have a meat allergy, because a subset who develop a strong immune response to the carbohydrate molecule may also develop a food allergy when they eat mammalian products, such as beef, pork, lamb, venison, rabbit, according to Mayo Clinic.
Symptoms range from mild to severe reactions from an itchy rash or hives to difficulty breathing and swelling of the lips or tongue that can require immediate emergency care, per the CDC.
Unlike other reactions from typical food allergies, like peanuts or shellfish, which occur within minutes, alpha-gal allergy is delayed within three to eight hours after an exposure, according to the allergy society.
Ticks hide in grasses and wooded areas across the United States and tick-borne diseases are on the rise, so it’s important to know how to prevent tick bites as the warmth of spring season lures them into the open, according to the CDC.
“Ticks ‘quest,’ they hang on some vegetation with their back legs while holding out front legs to grasp a host that walks by,” said Dr. Amy Korman, an entomology expert.
“Use clean, fine-tipped tweezers to grasp the tick as close to the skin’s surface as possible. Pull upward with steady, even pressure,” according to the CDC.
The agency warns to avoid twisting the tick when removing it, because that may leave part of the tick embedded in the skin, recommending instead if the tick can’t be easily removed with tweezers, to leave it alone and let the skin heal on its own.
And don’t forget to clean the bite area and wash your hands with either rubbing alcohol or soap and water.
The CDC notes other prevention strategies include avoiding places where ticks lurk, like wooded or brushy areas, wearing long sleeves and pants when camping or hiking, treating clothing with at least 0.5% permethrin products and using EPA registered repellents that can be found here.
And the agency reminds to always check for ticks after you return home, wash all clothes in hot water afterwards and shower to remove loose ticks.
And not even former presidents are immune to tick bites.
In the summer of 2007, President George W. Bush developed a rash on his lower left leg, which was diagnosed as Lyme disease by the White House physicians, according to a 2007 Washington Post report.
But given his frequent visits to Texas in the summer, some experts suggested the diagnosis was incorrect, instead thinking the rash was most likely southern-tick-associated-rash-illness, otherwise known as STARI.
STARI is caused by the lone star tick, the tick most implicated in alpha-gal syndrome, and although its rash mimics the “bulls-eye” rash typical of Lyme disease, it is one tick that is endemic in Lone Star State whereas Lyme disease is not, per the Post report.
The CDC provides this handout on tips and common questions regarding what to do after a tick bite, including symptoms to watch for and tips on how to remove a tick.