Overlapping Esophageal Disorders: A Population-Based Comparative Study of Eosinophilic Esophagitis Patients Also Diagnosed With Achalasia

Background: Eosinophilic Esophagitis (EoE) and achalasia are distinct esophageal disorders with overlapping symptoms, complicating diagnosis and treatment. While previous studies examined EoE among achalasia patients, less is known about the inverse relationship. We aimed to characterize features of EoE patients with and without the diagnosis of comorbid achalasia, as well as the temporal relationship between them. Methods: A retrospective, population-based cohort study was conducted using the Clalit Health Services database, covering over 5 million individuals. Patients diagnosed with EoE between 2000 and 2025 were included. Demographic, clinical, laboratory, and treatment data were compared between EoE patients with and without achalasia. Direct matching according to age, biological sex and ethnicity was used to identify independent predictors of achalasia. Results: Among 2496 EoE patients (median age 14, IQR 6.3–29.8 years; 73.2% male), 51 (2.0%) had achalasia, including 10 pediatric cases (0.6% of 1609 children). Achalasia preceded the EoE diagnosis in 20 patients (39.2%), occurred within 30 days in 20 (39.2%), and followed in 11 (21.6%). Compared to EoE-only patients, those with achalasia were older and had significantly higher rates of esophageal complications such as food impaction (23.5% vs. 12%, p = 0.013), esophageal stricture (11.8% vs. 4.6%, p = 0.017) and Barrett's esophagus (3.9% vs. 0.9%, p = 0.029). However, it had fewer atopic characteristics such as food allergy (3.9% vs. 24.7%, p < 0.001) and peripheral eosinophilia (15.7% vs. 29.5%). However, after direct matching there was no statistical difference. Conclusions: The concomitant diagnosis of achalasia occurs in a notable subset of EoE patients and tends to precede or coincide with EoE, suggesting that eosinophilic inflammation may be secondary in some cases. Awareness of this overlap may improve diagnostic elucidation in identifying the primary underlying process (eosinophilic infiltration or dysmotility) and diagnosis (EoE or achalasia).