Functional dyspepsia is associated with duodenal eosinophilia in an Australian paediatric cohort

Summary Background The pathophysiology of functional dyspepsia ( FD ) remains unknown. Duodenal eosinophil infiltration has been reported. Aim To assess the association between dyspeptic symptoms and duodenal eosinophilia in children undergoing upper gastrointestinal endoscopy. Methods In this retrospective cohort study, children with normal upper endoscopy and routine histology at a single tertiary paediatric centre between 2010 and 2014 were included. FD was defined as epigastric pain or discomfort >2 months without response to acid suppression. Controls presented with nonerosive reflux disease, dysphagia or rumination syndrome. Intramucosal eosinophil counts were compared between the groups using uni‐ and multivariate regression analyses. Results Thirty‐six cases and 36 nonmatched controls were identified. Atopic history (39% vs. 25%) and psychological comorbidity (53% vs. 39%; both P = 0.2) were frequent in cases and controls. Self‐reported nausea (64% vs. 17%; P < 0.0001), lethargy (19% vs. 0%; P = 0.005) and family functional gastrointestinal disorder( FGID ) (28% vs. 3%; P = 0.003) were more common in cases than controls. Duodenal eosinophil counts [median ( IQR ): 151 (118–207) vs. 76 (60–106) per mm 2 ; P < 0.001] were significantly higher in cases than controls with >112 eosinophils per mm 2 predictive for FD ( OR : 33.6, 95% CI : 7.1–159.0; P < 0.001). Duodenal eosinophilia was associated with weight loss ( OR : 7.1, 95% CI : 1.1–45.5; P = 0.04). Conclusions Functional dyspepsia in children is strongly associated with duodenal eosinophilia, in the absence of endoscopic or routine histological findings. Frequent atopic and psychological comorbidity illustrate likely multifactorial mechanisms.