Red Meat Allergy May Be An Expanding Problem

Re-examination revealed that alpha-gal allergy resulted in a change in the identification of definitive anaphylaxis triggers in 25% of cases.

Phillip L. Lieberman, MD

New data from a private, university allergy clinic has shown that there may be growth in the number of cases of anaphylaxis caused by galactose-alpha-1,3-galactose (alpha-gal) allergy—commonly known as red meat allergy.

The team, led by Angela Fadahunsi, MD, sought to determine whether the indicators and etiologies of anaphylaxis were altered from their original determination over the course of time in an ongoing series of studies.

A dataset of 281 cases—222 of which were determined to be the International Classification of Disease (ICD) code 995.0, anaphylactic shock—were collected, with the mean age of patients being 41 years (range, 9—78 years). The cases were recorded from the clinic since 1993, and data revealed that 40% (n = 88) of the cases had a definite trigger and 26% (n = 58) had a probable trigger. The cause of the anaphylaxis was unknown in 34% (n = 76) cases.

“Interestingly, among cases of anaphylaxis with a definitive cause, the most common trigger was a reaction to galactose-alpha-1, 3-galactose, better known as alpha-gal,” author Phillip L. Lieberman, MD, FAAAAI, said in a statement. “That is the compound that patients with mammalian meat allergy react to after ingesting red meats like beef or pork.”

Earlier reports from the clinic did not fully explain alpha-gal as the trigger—prior to the updated data, 59% of the cases (n = 131) of anaphylaxis were caused by an unknown source. The drop of unknown causes of anaphylaxis in one-quarter of the cases is, according to the researchers, largely due to the increase in alpha-gal cases.

The researchers declared the second-leading cause to be food allergy, consisting of 25 cases (28%). Alpha-gal was the leading cause at 32% of cases (n = 28).

“There has been such an influx in anaphylaxis caused by alpha-gal, that the rate of anaphylaxis without a clear cause has dropped 25%,” Thanai Pongdee, MD, FAAAAI, said in a statement. “The correct diagnosis of anaphylaxis is paramount for patient care, and understanding common causes is vital in this regard.”

The researchers concluded that alpha-gal allergy may be an increasing problem, which could have severe implications for patients with alpha-gal allergy, as “correct diagnosis of anaphylaxis is paramount for patient care, and understanding common etiologies [is] vital in this regard,” they wrote.

The results of the study were presented at the 2018 American Academy of Allergy, Asthma, and Immunology/World Allergy Organization Joint Congress in Orlando, Florida.

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