Ticks can cause lots of different diseases in people -- Rocky Mountain spotted fever, Lyme disease, Tularemia and many others. One of the strangest conditions triggered by a tick bite is an allergy to red meats, including beef, pork, venison and lamb. Very rarely, people with this allergy also react to cow's milk and gelatins found in some medications. You know what else is really strange about tick bites leading to red meat allergy? Symptoms can range from hives, swelling, wheezing, nausea and vomiting all the way to life-threatening anaphylaxis. Sometimes anaphylaxis doesn't start until three to eight hours after eating the food you're allergic to. In other food allergies, like peanuts or shellfish, allergy symptoms happen within a few minutes.
The Lone Star tick, named for markings on its back resembling the state of Texas, commonly bites animals and humans. As our climate changes, these ticks aren't just found in the southern part of the United States, but all the way up north to Maine and into the Midwest through Iowa. If the Lone Star tick bites a cow or other mammal, the tick takes in a unique sugar from that animal called alpha-1, 3-galactose, usually shortened to alpha-gal. Then when the tick bites a person, the sugar is transferred and triggers the person's immune system to develop an allergy to meats containing that sugar. More and more cases of alpha-gal allergy are being reported as these ticks continue to spread in the United States.
There is no cure for the allergy. Everyone with this condition should avoid red meat and carry an epinephrine auto-injector in case they accidentally eat meat or order a dish in a restaurant that's been contaminated by meat. The American College of Allergy, Asthma and Immunology recommends anyone at risk for anaphylaxis always carry two epinephrine auto-injectors. Some people with this condition may lose the allergy over time if they're not re-infected by another tick bite.
What can you do to prevent alpha-gal allergy? Avoid ticks. If you're outdoors in a wooded area, spray your clothing and gear with products containing 0.5 percent permethrin. Use Environmental Protection Agency-registered insect repellents, like DEET. Avoid wooded and brushy areas with high grass and leaf litter, as they can contain ticks. And stay in the center of trails. After you come back indoors, check your body and clothing for ticks and shower as soon as you can.
What should you do if you suspect you have alpha-gal sensitivity? Remember that it can be a life-threatening condition. See a board-certified allergist who can evaluate you with testing to determine whether you have this strange allergy.
Michael Blaiss, MD, is a clinical professor of pediatrics at Medical College of Georgia in Augusta, Georgia, and executive medical director of the American College of Allergy, Asthma and Immunology. He received his medical degree from University of Tennessee Center for Health Sciences in Memphis. He was Chief Resident at University of Tennessee/Le Bonheur Children's Medical Center in Memphis and completed a fellowship in allergy/immunology at Ochsner Medical Foundation in New Orleans, Louisiana.
He is past president of the American College of Allergy, Asthma and Immunology. He served as treasurer of the American Board of Allergy and Clinical Immunology, a past member of the Board of Directors of the World Allergy Organization and past president of the Tennessee and Louisiana Societies of Allergy, Asthma and Immunology. Dr. Blaiss has published more than 100 scientific peer-reviewed articles and presented at more than 500 meetings and seminars throughout the world. In addition, he has been a member of the editorial boards for the Annals of Allergy, Asthma, and Immunology, World Allergy Organization Journal, Journal of Asthma, and Allergy and Asthma Proceedings, Hypersensitivity and American Journal of Rhinology and Allergy.