Irritable bowel syndrome (IBS) is notoriously difficult to treat and this situation is unlikely to change until the pathophysiology is better understood. There is no doubt that IBS is a multifactorial condition but it is likely that the relative contribution of the various factors involved varies from patient to patient. Consequently, in some individuals one mechanism may have such a strong effect that its elimination may lead to a substantial improvement in symptoms. This paper describes a patient with severe asthma and IBS where the administration of an anti-Immunoglobulin E (IgE) monoclonal antibody not only improved her asthma but also resulted in an almost complete resolution of her IBS symptoms. This observation suggests that some form of allergic process, which may be mediated by IgE, might be driving IBS in some patients and there is evidence from the literature that atopy is more common in this condition. Therefore, in patients with IBS and atopy where the response to standard treatment is poor, it may be worth considering targeting the allergic diathesis. Possible approaches include skin testing with food antigens followed by an appropriate exclusion diet or pharmacological mast cell stabilization.
Keywords: Xolair; atopy; irritable bowel syndrome; omalizumab.