B35-28 Not Your Average Wheeze: Early-Onset, ANCA-Negative EGPA in an Underrepresented Population

Abstract Introduction Eosinophilic granulomatosis with polyangiitis (EGPA), formerly Churg-Strauss syndrome, is a rare necrotizing vasculitis involving small- to medium-sized vessels, characterized by asthma, eosinophilia, and variable organ involvement. The disease typically progresses through prodromal, eosinophilic, and vasculitic phases, with most cases diagnosed in middle age. Early-onset EGPA is uncommon, and reports among Puerto Rican and Hispanic populations remain limited despite high asthma prevalence in these groups. Approximately 60% of cases are ANCA-negative, a phenotype more often associated with pulmonary-predominant disease than systemic vasculitis. Early recognition in the eosinophilic phase is essential to prevent irreversible organ damage. Case Presentation 35-year-old Puerto Rican man with adult-onset asthma and chronic allergic rhinitis presented with four days of worsening dry cough, nasal congestion, and mild dyspnea, accompanied by recent weight loss. He denied chest pain, hemoptysis, or gastrointestinal symptoms. He was afebrile, normotensive, and oxygenating at 96% on room air. Examination revealed diffuse wheezing and nasal mucosal edema. Laboratory studies showed leukocytosis with marked eosinophilia, hemoglobin 11.9 g/dL, and total IgE 1180 IU/mL. Renal and hepatic function were normal, and both MPO-ANCA and PR3-ANCA were negative. Chest CT revealed patchy bilateral migratory ground-glass infiltrates without consolidation or effusion, and sinus CT demonstrated diffuse mucosal thickening consistent with chronic rhinosinusitis. Echocardiography and neurologic evaluation were unremarkable. He was treated with intravenous methylprednisolone 60 mg daily, followed by an oral prednisone taper, leading to rapid clinical and hematologic improvement within 72 hours. The combination of asthma, eosinophilia, pulmonary infiltrates, and sinus disease met ≥4 ACR 1990 and ≥6 ACR/EULAR 2022 criteria, confirming EGPA. Discussion This case highlights early-onset, ANCA-negative EGPA in a young Hispanic patient, an underreported demographic. The ANCA-negative phenotype, representing most EGPA cases, commonly presents with eosinophilic lung disease rather than systemic vasculitis. Prompt recognition during the eosinophilic phase allowed timely corticosteroid therapy, preventing progression to irreversible organ involvement. This case underscores the need for diagnostic vigilance when evaluating young asthmatics with unexplained eosinophilia and pulmonary infiltrates, particularly in populations where EGPA is underrecognized. Conclusion EGPA should be considered in patients with asthma, marked eosinophilia, and migratory pulmonary infiltrates even when ANCA is negative. Early diagnosis and corticosteroid therapy are vital for preventing systemic vasculitic complications and improving outcomes, especially in underrepresented populations. This abstract is funded by: None