Lone star tick

Ticks are well-established in Iowa and cause a number of illnesses. Now, another species — the lone star tick (Ambylomma americanum), typically found in the southern U.S. — appears to be making inroads here, and it brings with it a surprising reaction.

Scott Commins, an allergist at the University of North Carolina-Chapel Hill, was one of the first doctors in 2007 to recognize that patients coming in with allergic reactions to red meat had also been bitten by a lone star tick. In 2017, he told Today that UNC had treated a total of 537 cases of tick-related meat allergies. This month, he told NPR “we’re confident the number is over 5,000 [cases]…in the U.S. alone.”

There is still a lot to learn about the alpha-gal allergy. Alpha gal is a sugar that animals – cows, pigs, lamb – make in their bodies. Humans do not make it, but all humans make an immune response to it.

Lone star tick closeupSo how does a tick bite cause the allergy?

Scientists currently theorize that ticks inject humans with alpha gal when they bite. The ticks likely get it feeding off wild animals, such as mice or squirrels, that also carry alpha gal. Or, it’s possible that ticks activate the response in another way. A definitive answer requires additional research.

Commins says, “Whatever the tick is doing, it seems that it’s a very potent awakener for our immune system to produce antibodies.”

Although the tick bite may not cause any initial symptoms, it triggers the immune system to make antibodies for the alpha gal sugar as if it were a pathogen. The next time the tick-bitten victim enjoys a meal with meat from any kind of mammal – beef, lamb, pork, goat (all of which also contain alpha gal) – their immune system will spring into action.

The red meat allergy condition has been officially named the Southern Tick-Associated Rash Illness or STARI. The severity of the allergic reaction varies from person to person, and usually includes hives and gastro-intestinal distress about six hours later.

Commonly reported symptoms:

  • Hives or skin rash
  • Nausea, stomach cramps, indigestion, vomiting, diarrhea
  • Stuffy/runny nose
  • Sneezing
  • Headaches
  • Asthma
  • Anaphylaxis, a severe and potentially deadly allergic reaction that restricts breathing

Scientists don’t know much about the permanence of the allergy; but they have discovered that some patients also develop an allergic reaction to dairy.

Lone star ticks have also been known to spread Rocky Mountain fever and a number of other bacterial infections that cause rashes and fevers.

The best thing to do is to avoid getting bit in the first place by using bug spray and wearing long-sleeved clothing when walking through woods, shrubbery, or tall grasses.

STARI diagnosis

Symptoms of STARI can vary from person to person, and you may not always experience the same symptoms during every reaction. Allergic reactions to food can affect the skin, respiratory tract, gastrointestinal tract, and cardiovascular system. Meat allergies may also develop at various ages.

If you suspect that you have a meat allergy, see an allergist, who will decide which tests to perform, determine if a food allergy exists, and work with you on managing your allergy.

The Knoxville Hospital & Clinics’ allergy program is overseen by Dr. Michael Van NattaTo make an appointment to see Dr. Van Natta, call 641-842-7006.


Article references: American College of Allergy, Asthma, and Immunology; CDC; Today; NPR

CDC Seeks Study Participants

The Centers for Disease Control and Prevention (CDC) is conducting a study to investigate tick bite illnesses that result in erythema migrans-like skin rashes occurring in areas where Lyme disease exists, including Iowa. Learn more about the study and whether you might fit the participant criteria. https://www.cdc.gov/stari/index.html

The information on this blog is provided for general information purposes and is not a substitute for professional medical advice, care, treatment or evaluation; nor should it be used in diagnosing a health condition. You are encouraged to consult your health care provider if you or a family member has or suspect you have a medical problem.