Abstract Background Eosinophilic granulomatosis with polyangiitis (EGPA), formerly Churg-Strauss syndrome, is a rare ANCA-associated vasculitis featuring adult-onset asthma, eosinophilia, and multisystem vasculitis. It often overlaps with chronic eosinophilic pneumonia (CEP), a Th2-driven, lung-limited disorder (3% of interstitial lung diseases) with eosinophilic alveolar infiltration, female predominance (2:1), and asthma in 60-75% of cases. Differentiation is vital: EGPA requires immunosuppression to prevent organ damage, while CEP is steroid-responsive. Case A 45-year-old man with adult-onset asthma, chronic eosinophilia, GERD, and post-cholesteatoma hearing loss presented with dyspnea, wheezing, near-syncope, productive cough, hemoptysis, night sweats, weight loss, myalgias, and arm heaviness. Exam showed fever (38.3 °C), tachycardia (110 bpm), 94% SpO2, and bilateral wheezes. Travel history included recent international trips; medications: omeprazole, prednisone (5 mg), budesonide-formoterol, ketoprofen. Labs: leukocytosis (13,750/µL) with 77% eosinophils (10.62 × 10³/µL), elevated IgE (307 IU/mL), CRP (35 mg/L), ESR (54 mm/hr), MPO-ANCA ≥149 U (p-ANCA+). HRCT: bilateral lower-lobe opacities, tree-in-bud nodularity, centrilobular nodules in ground-glass, favoring EGPA over CEP’s typical peripheral consolidations. Infectious workup negative. BAL: 49% eosinophils; biopsies: eosinophil-rich inflammation without vasculitis. Diagnosis: EGPA (ACR criteria met: asthma, eosinophilia 10%, infiltrates, neuropathy, ANCA+). Treatment: IV methylprednisolone (40 mg daily) resolved pulmonary symptoms; rebound eosinophilia prompted pulse steroids (1 g ×3). Discharged on prednisone taper; post-discharge small bowel obstruction (EGPA-related) resolved conservatively. Mepolizumab (300 mg SC monthly) initiated; at 3 months, asymptomatic on 5 mg prednisone. Discussion This case highlights EGPA-CEP overlap, with initial CEP-like features (subacute symptoms, BAL eosinophils) masking systemic vasculitis. Clues to EGPA: ANCA+, extrapulmonary involvement (neuropathy, GI), centrilobular nodules. EGPA phases (allergic/eosinophilic/vasculitic) risk cardiac/GI complications untreated. Steroids induced remission; mepolizumab enabled tapering per MIRRA trial (higher remission, fewer relapses). Conclusion EGPA may mimic CEP, delaying diagnosis. ANCA testing, systemic assessment, and imaging aid differentiation. Biologics like mepolizumab offer steroid-sparing control, improving outcomes. This abstract is funded by: none
Ogaryan et al. (2026) studied this question.