Abstract
Hypereosinophilic syndrome (HES) is a spectrum of diseases characterised by an elevated eosinophilic count causing end-organ damage. Differential diagnoses of hypereosinophilia are vast and include drug hypersensitivities, allergies, infections, cancers, autoimmune disorders and rare eosinophilic syndromes. Herein, we describe a case of a patient presenting with gastrointestinal (GI) symptoms including progressive dysphagia, abdominal distension, vomiting, diarrhoea and abdominal pain with significant peripheral eosinophilia who was found to have an overlap HES involving the GI tract. This patient's eosinophilia was rapidly corrected with intravenous methylprednisolone, and the patient experienced gradual resolution of clinical symptoms with maintenance oral prednisone. Due to the rarity and diverse presentation of HES, there are few large, longitudinal studies that describe disease progression and inform treatment guidelines. This case demonstrates the difficulty in designing a treatment regimen for these patients and emphasises the clinical need for improved understanding of HES.