They can give you a life-threatening allergy to red meat and possibly dairy products
As if ticks weren’t bad enough carrying infections such as Lyme disease, anaplasmosis, babesiosis, Rocky Mountain spotted fever and Powassan virus, there’s another reason to consider them public enemy No. 1. In some cases, a bite from a lone star tick – found from Pennsylvania down through the southern United States – can cause an allergic reaction to red meat.
Unfortunately, for some people, the response can be a severe, life-threatening one.
The culprit isn’t a virus, or bacteria like with other tick diseases. It’s alpha-gal, a sugar molecule found in non-primates (animals other than lemurs, monkeys, apes and humans) that can be picked up by certain ticks when they bite those animals.
“If the affected tick happens to bite you, the alpha-gal sugar molecule is deposited right into your bloodstream,” says Robert Zemble, MD, Chief, Division of Allergy, with LVPG Allergy, Asthma and Immunology–1605 N. Cedar Crest, part of Jefferson Health. “People who develop antibodies to the alpha-gal molecule will get the allergy, which is your immune system overreacting to something that typically should be harmless.”
Common allergic reactions range from hives and dizziness to digestive issues, including diarrhea, stomach pain and vomiting. Sometimes the reaction is severe (anaphylaxis). “A person’s blood pressure may drop if the cardiovascular system is affected or the airway may become blocked if there is swelling in the throat,” Dr. Zemble says.
Most reactions are to the proteins in beef, pork, lamb and other mammals. The allergy does not affect seafood, chicken or turkey, and eggs are safe to eat. As opposed to classical food allergy reactions, which typically occur within 30 minutes of eating, alpha-gal leads to delayed reactions, usually two to six hours later.
People can have the same allergic reaction after eating products derived from non-primate mammals, such as dairy products or gelatin, a flavorless, colorless thickening agent made from the collagen in animal bones, skin and connective tissues.
A blood test in a clinical setting along with a review of medical history are the best tools clinicians have for diagnosing alpha-gal syndrome. The blood test detects the presence of antibodies, but not all patients with a positive result develop the condition.
As with all allergic reactions, Dr. Zemble says, avoidance is the best medicine. “If you have it, avoid red meats, and you may need to avoid dairy products and gelatin,” he says. “Those who are sensitive should be aware that some vaccines contain gelatin, and certain implants, such as heart valves, come from mammals and may need to be avoided.”
He notes it’s good to have an anaphylaxis plan ready that includes an epinephrine auto-injector – used to treat severe allergic reactions – and when to use it. “You want to try to prevent further tick bites, because more bites can increase severity of the reaction,” he says. “If you can avoid tick bites, you may lose sensitivity over time.”
Dr. Zemble says that while the number of cases of alpha-gal syndrome in the Lehigh Valley is on the increase, there are not as many as there are of Lyme disease, for example. “The highest numbers of alpha-gal cases nearby are in the mid-Atlantic region – Virginia, North Carolina and Delaware. The distribution extends through Long Island, west through Kentucky, Tennessee and the midwestern states, and south to Florida and Texas,” he says. “But we do have some cases in Pennsylvania, even now.”
Identifying the tick can be tricky. Adult females are the largest and distinguished by a white dot on their back. Adult males are slightly smaller than adult females. Nymphs are about the size of a poppy seed while the larvae are slightly larger than the head of a pin. Therefore, the best plan is no tick at all.
“People should always be aware that ticks carry disease,” he says. “Whether it’s the deer tick or lone star tick, you want to avoid tick bites regardless. You don’t want your skin exposed outdoors; do tick checks every time you come in from outside and use whatever kind of measures you can, such as a DEET-based spray.”
“Everyone has a degree of risk,” he says.
