Food allergy and atopy might be underlying factors in some patients with irritable bowel syndrome (IBS), two new studies suggest.
In fact, the constellation of allergic asthma, rhinitis, and eczema in a subgroup of IBS patients goes hand-in-hand with diarrhea and gastrointestinal reactions to food.
"The thinking is that if you can figure out their food allergies, you can really improve their diarrhea and abdominal pain. And we see in the clinic that they do feel better," said senior investigator Mary Tobin, MD, an allergist at the Rush University Medical Center in Chicago.
The findings of both studies were presented here at the American College of Allergy, Asthma & Immunology 2015 Annual Scientific Meeting.
In a previous study that Dr Tobin was involved in, patients with atopic symptoms were shown to be more likely to have IBS than patients without atopic symptoms (odds ratio, 3.2) (Ann Allergy Asthma Immunol. 2008;100:49-53).
In their current study, Dr Tobin and her colleagues identified a possible connection between the allergic airway and the allergic gut.
They evaluated 122 with atopic IBS and 32 with nonatopic IBS. Median age was 34.2 years.
In patients with atopic IBS, the predominant GI symptom was diarrhea, whereas in those with nonatopic IBS, the predominant GI symptom was constipation (P < .05).
The diarrhea is possibly from increased mucosal mast cells and gut permeability, which are associated with IgE-mediated reactions, such as food allergy, Dr Tobin explained.
Testing for Food Allergies
In the second study, 48 patients with atopic IBS, 65% of whom reported GI symptoms after eating specific foods, underwent skin prick testing for a panel of food allergens, including peanut, tree nuts, fish, shellfish, egg, milk, cereals, meats, poultry, fruits, vegetables, and legumes. Mean age was 37.2 years.