Eosinophilic colitis in children: a new and elusive enemy?

Purpose: Eosinophilic gastrointestinal disorders are rare in children and present with a broad spectrum of non-specific symptoms. To date, no guidelines for diagnosis, therapy and follow-up are validated. Aim of our study is to focus on eosinophilic colitis (EC), to determine a possible correlation between associated disorders, macroscopic findings and treatment/follow up. Methods: Retrospective study from 2015 to 2019 including all colonoscopies performed at our Institution. Eosinophilic colitis was defined according to the threshold identified by Collins: > 100 Eo/Hpf: right colon, > 84 Eo/Hpf transverse and left colon, > 64 Eo/Hpf sigma and rectum. We excluded colonoscopy in patients with IBD or other diseases causing hypereosinophilia (i.e., parasite infection, GVHD). Results: Among 399 colonoscopies performed in 355 patients, we made 50 diagnosis of EC, 36 males, 14 females, median age 8.5 (3–17). Symptoms leading to endoscopy were recurrent abdominal pain (66%), chronic diarrhea (64%), and chronic constipation (8%). Two patients presented with GI bleeding and one with weight loss. Macroscopic findings were mostly normal or lymphoid nodular hypertrophy presenting different endoscopic features. In seven children (14%) we found history of allergy and atopy. 22 children present a diagnosis of autistic spectrum disorder (ASD) with a prevalence higher than in the overall population (44% vs 28.5%, p = 0.03). According to symptoms, treatment consist variably of steroids, six food elimination diet, mesalamine. For patients with available follow-up, we found histological persistence of Eosinophils in 75%, even in patients with symptoms relief. Conclusion: This study focus attention on EC as a new challenging pathology. Multicentric randomized clinical trials are needed to understand physiopathological mechanisms to validate a possible endoscopic score and related histological threshold, and to standardize therapy according to clinical features and instrumental findings. The high prevalence of EC in ASD need further specific research.