Prevalence of Antihistamine Responsive Irritable Bowel Syndrome With Diarrhea

We have published a series of 5 patients with chronic post prandial diarrhea (PPD) that begins within 3 hours after eating, associated with dermatographia, responsive to antihistamines \[2\]. In these cases, no underlying causes were identified to explain PPD; diagnoses of food allergy, lactose intolerance, celiac disease, dumping syndromes, inflammatory bowel disease, systemic mastocytosis were excluded. Patients with the syndrome have prior histories of chronic urticaria and experience associated transient symptoms of flushing, headache, tachycardia, and abdominal bloating during PPD episodes. This syndrome, except for our published report, have not been previously described in the medical literature. Patients with systemic mastocytosis and mast cell activation syndrome experience PPD but along with anaphylactic manifestations (e.g. wheezing, hypotension) and measurable mast cell biomarkers are identifiable in affected patients (i.e. serum mast cell tryptase or 24 hour urine methylhistamine, PGF2a). Therefore, it is important to characterize PPD responsive to antihistamines in a general GI patient population and to publish our findings. The impact on human health will be substantial; we found that these patients are undiagnosed and untreated for many years. Our aim is to recruit 50-100 patients from the UC Health affiliated gastroenterology clinics with access UC health which has 300-500 potential subjects. We would need to recruit 10-20% percentage of these potential subjects. Kris Ramprasad MD, a faculty member in the Division of Gastroenterology, David Bernstein MD, a faculty member in the Division of Allergy and Rheumatology, allergy fellows and GI fellows will direct and implement subject screening and consenting.