[DIAGNOSIS OF ANTINEUTROPHIL CYTOPLASMIC ANTIBODY-NEGATIVE EOSINOPHILIC GRANULOMATOSIS WITH POLYANGIITIS BASED ON...

Eosinophilic granulomatosis with polyangiitis (EGPA) is a form of necrotizing vasculitis typically accompanied by asthma and eosinophilia. Only a small number of cases lacking asthma symptoms have been reported.

A man in his fifties with no history of asthma, allergic rhinitis, or eosinophilic sinusitis was admitted with fever, shortness of breath, and a rash. Peripheral blood eosinophilia and multi-organ dysfunction were also observed. Myocardial and gastrointestinal tract biopsies revealed eosinophil-predominant inflammatory infiltrates. Renal biopsy revealed pauci-immune necrotizing crescentic glomerulonephritis with eosinophilic interstitial nephritis. Although anti-neutrophil cytoplasmic antibodies (ANCA) were negative, the patient was diagnosed with EGPA based on the classification criteria.

Systemic corticosteroid therapy was initiated, followed by the administration of intravenous cyclophosphamide and immunoglobulin. The patient achieved remission and was discharged from the hospital.

Even in ANCA-negative patients without asthma, the presence of eosinophilia and characteristic renal pathological findings provides important diagnostic clues. EGPA should be included in the differential diagnosis of renal impairment with eosinophilia, and an early renal biopsy should be considered.