Irritable bowel syndrome common in those with allergies

Researchers have found that people with symptoms of allergy have a high incidence of irritable bowel syndrome, suggesting a link between atopic disease and the bowel disorder.

Irritable bowel syndrome (IBS) has long been associated with various mental health issues such as depression but this new research shows that the correlation between allergic conditions and IBS is even stronger.

The study was conducted by researchers from the Department of Immunology/Microbiology at Rush University Medical Center, Chicago. The results appearand in this months edition of the Annals of Allergy, Asthma & Immunology, the journal of the American College of Allergy, Asthma and Immunology (ACAAI).

Various findings from previous studies have suggested indirectly that allergen exposure may lead to IBS symptoms in some patients, but the correlation between the incidences of allergy and IBS has not been studied.

A link is not unexpected since chemicals released during allergic reactions, such as histamine, are known to have an effect on the functioning of the digestive system. Histamine for example triggers the release of stomach acid, and affects muscle contraction in the intestines.

Mary C. Tobin, M.D, and colleagues looked at the medical histories and current symptoms of 125 adults and uncovered striking patterns of co-existing conditions.

They found that for people with allergic rhinitis (hayfever) the chances of having IBS were 2.67 times those for an otherwise healthy person, and for someone with allergic eczema the chances were even higher at 3.85 times the average. These figures compare with the chances of someone with depression having IBS of 2.56 times the average.

In a finding that closely matches results from previous research, asthma and irritable bowel syndrome were reported by 12 of 41 patients (29 per cent).

Dr. Tobin and colleagues write "The reported presence of allergic dermatitis was highly correlated to the presence of IBS in our population," investigators noted. "In atopic disease, allergic dermatitis is the first step of the 'atopic march.' In early childhood, AE (allergic eczema) is frequently associated with gastrointestinal dysfunction and food allergy. A clinical history of AE may be a useful marker for patients with gut hypersensitivity and atopic IBS."

The researchers conclude that "this subgroup of IBS (atopic IBS) be considered separately from patients with IBS without atopic symptoms, because they may have distinct pathophysiologic features and may benefit from specific therapeutic interventions."

Effectively what the researchers are saying is that when a patient has both allergic conditions and IBS, that treating the allergy symptoms may also lead to a resolution or improvemtn of the IBS symptoms. It is therefore important that both allergies and IBS be tackled together.

Source: Tobin MC et al (2008) Atopic irritable bowel syndrome: a novel subgroup of irritable bowel syndrome with allergic manifestations Annals of Allergy Asthma and Immunology 100:49-53