Garlic allergies more common, dangerous than suspected
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SAN ANTONIO — Garlic allergy may be more common and more dangerous than providers realize, according to data presented at the American Academy of Allergy, Asthma & Immunology Annual Meeting.
“People need to be aware that it does occur, and it can be an issue,” Thomas B. Casale, MD, professor of internal medicine and pediatrics and chief of clinical and translational research in the division of allergy, asthma and immunology, University of South Florida Morsani College of Medicine, told Healio.
IgE-mediated allergic reactions to garlic, or Allium sativum, are rarely reported even though it is commonly used worldwide, the researchers said.
Using data collected between May 2017 and October 2021, the researchers found 132 patients (58% female; 80% white) with garlic allergy among the approximately 13,000 entries in the Food Allergy Research & Education (FARE) Patient Registry.
“They reported allergies to over 200 different things,” Casale said, adding that garlic was the leading allergen in the “other” category after the “big nine” allergens of milk, eggs, fin fish, shellfish, peanuts, tree nuts, wheat, soy and sesame.
“This was very surprising to me,” Casale said.
Age at diagnosis ranged across the population, including 36% diagnosed at age 10 years or younger, 23% diagnosed between ages 11 and 25 years, 37% diagnosed between ages 26 and 64 years and 4% diagnosed at age 65 years and older.
“They tended to have been diagnosed at an older age,” Walaa Hamadi, MD, second year fellow in allergy and immunology at the Morsani College of Medicine, told Healio. “They had a higher rate of family history of food allergies as well.”
Patients also were more likely to have comorbid allergic rhinitis, asthma or atopic dermatitis.
Specifically, 39% of those with garlic only allergy and 28% of those with a different single food allergy had allergic rhinitis; 46% of those with garlic only allergy and 32% of those with a different single food allergy had asthma; and 47% of those with garlic only allergy and 33% with a different single food allergy had atopic dermatitis.
Further, 34 of these patients also reported an allergy to another Allium species such as onion, shallot, leek, scallion or chives. The researchers noted that the only clinically relevant garlic allergen identified to date is alliin lyase, which showed strong cross-reactivity with alliin lyases from other Allium species.
Two-thirds of these garlic allergies were diagnosed by an allergist, including skin prick tests (74%), significant IgE (58%), food diaries (26%), food elimination (25%) and oral food challenge (10%).
Hamadi noted that the number of patients who went to the hospital because of their reactions was significant.
“It wasn’t like, ‘I went to my allergist and got evaluated.’ It was, ‘No, I ended up in the hospital because of this reaction,’” she said. “I think that was what stood out to me the most.”
Overall, 56% of the patients with a reaction to garlic allergy presented to the ED, 19% were hospitalized and 6% were admitted to the intensive care unit. Combined with the lack of awareness, these reactions present real dangers, the researchers said.
“A lot of times, we see patients that have an acute allergic reaction after they’re eating, and they have no idea where it came from,” Casale said.
Garlic’s popularity adds to the risk, the researchers continued.
“I feel it’s even more prevalent than peanut, because you can’t get away from it,” Hamadi said. “Everything seems to have garlic extract, so it can be scary.”
“If patients do have garlic allergy, we would tell them to avoid it and to probably carry an EpiPen because garlic is in so many different things,” Casale said.
The researchers advised practitioners to be aware that garlic allergies are a potential diagnosis.
“Keep in mind that garlic might be more common than thought and to think about it when you find somebody and you’re not sure what they’re allergic to, but you’re convinced they have an IgE-mediated reaction to food,” Hamadi said.
“I think we need to publish it and make people aware that this exists,” Casale said.