The results of a new study performed at a University of Tennessee Health Science Center (UTHSC) affiliate clinic showed that alpha-gal (a complex sugar found in red meat from beef, pork, venison, etc.) was the most common known cause of red meat allergy anaphylaxis, a severe and potentially life-threatening allergic reaction. What’s additionally noteworthy is that these allergic reactions may all stem from a tick bite from the Lone Star tick.
The findings, which have been gaining national interest, were presented in a manuscript titled, “The changing face of anaphylaxis in adults and adolescents,” published in the Annals of Allergy, Asthma and Immunology, a scientific publication of the American College of Allergy, Asthma and Immunology (ACAAI).
The study participants, all of whom were evaluated at a private UTHSC-affiliated allergy and immunology clinic, were seen between 2006 and 2016. Since alpha-gal allergies had not yet been identified until 2008, previous reviews did not have this diagnosis included as a possible cause. However, due to increased awareness and more diagnostic testing available, alpha-gal allergy went from an unknown entity to the most commonly identified cause of anaphylaxis at the site.
“Of the 218 cases of anaphylaxis we reviewed, 33 percent were from alpha gal,” said Debendra N. Pattanaik, MD, MBBS, FACR, FAAAI, associate professor of rheumatology in the UTHSC College of Medicine and principal investigator of the study. “When we did the same review in 1993, and again in 2006, we had a great many cases, where the cause of the anaphylaxis couldn’t be identified. That number of unidentified cases dropped from 59 percent in 2006 to 35 percent in this report — probably from the number of identified alpha-gal cases. Our research clearly identified alpha-gal as the cause of anaphylaxis in the majority of cases where the cause was detected. Food allergies were the second leading cause, accounting for 24 percent.”
The research also reported that antibodies to alpha-gal are caused by bites of larval or adult Lone Star ticks. UTHSC is located in the central area of geographic distribution for this particular family of ticks in the United States. Jay Lieberman, MD, vice chair of the ACAAI Food Allergy Committee and co-author to the study, states that Tennessee is a state with a big population of Lone Star ticks, and that might have influenced the large number of alpha gal cases identified.
“The Lone Star tick is predominantly found in the southeastern United States and we would expect a higher frequency of anaphylaxis cases in this region would be due to alpha gal,” said Lieberman, who also serves as an associate professor of pediatrics at UTHSC. “However, the tick can be found in many states outside this region and there are already more cases being reported nationwide.”