Red meat allergies caused by tick bites are on the rise
Experts say that this year's tick season is shaping up to be possibly the worst in recent memory. Beyond Lyme disease and other tick-borne ailments, a new threat is emerging from ticks whose bites can prompt an allergy to red meat.
Can a tick bite make you allergic to red meat?
Tick bites can cause a long list of problems, and now there is evidence that a tick bite could be the trigger for an allergy to red meat, according to Dr. Scott Commins, Associate Professor of Medicine in the Department of Allergy & Immunology at the University of North Carolina.
A woman from Maryland had a horrible reaction while eating an Italian-style pork sausage last year, and her symptoms were all linked back to a tick bite she got three weeks earlier, while walking her dog.
What is the association between ticks and red meat?
In susceptible individuals, multiple tick bites appear to result in sensitization to alpha-gal, a substance present in red meat, which then causes an allergic reaction, according to Dr. Commins.
“Over 90% of patients who develop red meat allergy due to alpha-gal report tick bites," he told ABC News. "Many recall a specific bite that had a ‘bad reaction’ or ‘was slow to heal’ or ‘itched for weeks.'"
Dr. Commins and his team recently published a few cases of rising IgE (antibody levels in the blood produced by the immune system) following tick bites. They also have some preliminary evidence that by injecting tick salivary gland extract into mice, they can reproduce this red meat allergy.
What are symptoms?
In adults, the most common symptoms of this red-meat allergy include itching, hives, and gastrointestinal symptoms, according to Commins.
One unusual feature: symptoms can be relatively delayed in onset, beginning as quickly as several minutes, or as delayed as 3-6 hours after eating red meat, Commins said. Symptoms may occur in the middle of the night, for instance, after eating meat for dinner.
Which ticks cause red-meat allergy?
Many ticks cause this, but one of the most commonly-identified in the U.S. is the Lone Star tick Amblyomma americanum. It it most frequently found in the Southeast portion of the U.S., but the range of the tick is expanding across other areas of the U.S.
How common is tick-induced red meat allergy?
Tick-induced red meat allergy, while not common, is widespread. It is more likely to be found in the eastern and southern parts of the U.S.
“We know of over 5,000 cases in the U.S.,” Dr. Commins told ABC News.
There are also cases reported in Europe, Australia, Sweden, and South Africa, he said.
The Center for Disease Prevention and Control (CDC) warns that tick-borne diseases are on the rise and prevention should be on everyone’s mind, particularly during the spring, summer, and early-fall when ticks are most active.
How is the allergy diagnosed/treated?
The diagnosis of meat allergy is challenging, but experts will generally diagnose this condition with a combination of the patient's medical history, blood or skin allergy testing, and, possibly, a “food challenge” - where meat is fed to the patient, and then they are observed for a reaction.
There’s no established treatment, but people who fear they are susceptible can avoid red meat, and learn how to use an EpiPen if needed for accidental exposures, Commins said. This allergy can become less severe over time.
Which food items need to be avoided?
“Beef, pork, lamb, goat, rabbit, buffalo, horse, etc," Commins said. "Particularly fatty cuts are the worse for causing more severe reactions. This includes organs meat as well."
“Occasionally dairy can be an issue but most patients are okay with dairy," Commins said. "And this should go away over two to three years as long as [there are] no additional tick bites…so take requisite tick precautions.”
How are tick-borne diseases prevented?
Wearing long-sleeved shirts and pants and enclosed shoes when you’re outdoors helps, according to the Centers for Disease Control and Prevention (CDC). Some people pull their socks up over the hems of their pants to make sure ticks can’t get in. The CDC also suggests wearing insect repellent containing DEET, and if you are walking through or brushing against vegetation, perform daily self-examinations for ticks and remove them.
Dr. Karine Tawagi is an Internal Medicine resident in Ann Arbor, Michigan working in the ABC News Medical Unit.
