Q: I have recently begun getting hives and diarrhea after eating foods containing garlic (which seems the only common denominator). Is it possible to be allergic to garlic, and should I see an allergist?
Dr. Sharma: It is possible to be allergic to garlic, but it appears to be rare and only a few cases have been reported in the medical literature. Most of these cases describe people who developed occupational asthma or contact dermatitis (a skin rash similar to eczema) due to garlic.
While immediate allergic reactions to garlic are the least likely, they can range from mild reactions such as hives and diarrhea to anaphylaxis. In several of the reported cases, there was a history of reactions after consuming raw garlic but tolerance to cooked garlic. This may suggest that the proteins in garlic responsible for the allergy are degraded by heat or the process of digestion.
In terms of getting symptoms evaluated, skin testing with fresh garlic and a garlic extract and/or blood testing was sometimes helpful in supporting the diagnosis. So it certainly seems reasonable to see an allergist, who can review the history to determine whether you are likely allergic to garlic. An allergist could also assess for other causes of your symptoms.
Dr. Sharma is an allergist, clinical researcher and Assistant Professor of Pediatrics. He is Associate Chief of the Division of Allergy and Immunology at Children’s National Medical Center in Washington D.C. and Director of the Food Allergy Program. He co-authors “The Food Allergy Experts” column in the American Edition of Allergic Living magazine. Questions submitted below will be considered for answer in the magazine.