Introduction:
An increase in the incidence of eosinophilic oesophagitis (EoE) in children is being observed worldwide. The diagnosis is confirmed by the morphological examination of the mucosa biopsies. The aim of our study was to evaluate the clinical course of EoE in the first year of diagnosis, and the effectiveness of the first-line treatment of EoE in children.

Material and methods:
This single-centre retrospective study included children with EoE newly diagnosed between January 2015 and December 2020. Patients were monitored after initial treatment and 12 months after diagnosis. The study assessed clinical, endoscopic, and histological responses to various therapeutic strategies.

Results:
Of the 27 children diagnosed with EoE, 19 were enrolled in the study. The median age of children with EoE was 9 years (range 2–17 years) and the majority were male (84.2%). The most frequent initial treatments were proton pump inhibitors (PPIs) (47.4%), also in combination with an elimination diet (36.8%). Clinical improvement was noted in 73.7% of cases after initial therapy and in 84.2% of patients after 12-month follow-up. However, endoscopic and histological improvement was observed less frequently, in 52.6% and 47.4% of patients, respectively. Forty-two per cent of children with EoE obtained clinical, endoscopic, and histological improvement, and the majority of them received PPIs in mono- or combination therapy with an elimination diet.

Conclusions:
Choosing an effective treatment that provides clinical, endoscopic, and histological improvement in patients with EoE is a challenge for clinicians. According to our observations, clinical improvement should not be a single indicator of treatment success; therefore, it is necessary to repeat upper endoscopy and oesophageal biopsy.