Eosinophilic granulomatosis with polyangiitis with an abnormally sized nasal polyposis in a 24-year-old male: a case report.

Introduction and importance: Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare, multisystem vasculitic disorder characterized by asthma, eosinophilia, and necrotizing granulomatous inflammation with vasculitis affecting small- to medium-sized vessels. EGPA is classified as an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis. Presentation of case: Here, we present a case of a 24-year-old male who came to our institution with complaints of progressive, bilateral, non-tender, non-erythematous nasal swelling since last year. Upon further inquiry, he was found to have asthma managed with inhaled short-acting bronchodilators and had recurrent episodes of rhinosinusitis in the past. After several supportive investigations, a diagnosis of EGPA with nasal polyposis was confirmed, and the patient was initially treated with intravenous corticosteroids, followed by oral doses for maintenance therapy after discharge. Discussion: In most cases, EGPA presents clinically with a history of asthma. Upper respiratory tract involvement occurs in 70-90% of cases, typically manifesting as rhinosinusitis and nasal polyposis. A positive ANCA - especially with a perinuclear pattern (p-ANCA) and antigen specificity for myeloperoxidase (MPO-ANCA) - is a hallmark of EGPA and aids in diagnosis. Treatment generally includes high-dose corticosteroids, with cyclophosphamide added in severe cases. Conclusion: Diagnosing EGPA can be challenging due to its variable clinical manifestations. Our case exhibited typical upper respiratory tract involvement; however, positive ANCA, p-ANCA, and MPO-ANCA findings were instrumental in confirming the diagnosis. Based on our literature review, we recommend that such cases be thoroughly evaluated and managed in hospital settings.