Eosinophilic esophagitis (EoE) is a chronic inflammatory disease manifesting clinically with symptoms of esophageal dysfunction and histologically with eosinophilic infiltration of the esophageal epithelium. The pathomechanism of EoE is multifactorial and not fully elucidated. The majority of patients with EoE suffer from food and/or inhalant allergy. An important role in the pathogenesis of EoE is attributed to a T2-dependent mechanism. Eosinophilic esophagitis often co-occurs with allergic rhinitis, allergic conjunctivitis, and asthma. As such, it is an important component of multimorbidity. Allergists may contribute to the early detection of eosinophilic esophagitis by noting subtle signs of dysphagia and referring patients for endoscopic examination. Due to the frequent comorbid allergies, all patients with suspected EoE should be diagnosed for allergy.