Sinusitis and Late-Onset Asthma: A Red Flag of Eosinophilic Granulomatosis With Polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare systemic disease that develops with necrotizing granulomatous inflammation and is characterized by eosinophilia, asthma, and small vessel vasculitis. We report the case of a 74-year-old woman with a history of asthma, admitted to the Emergency Room with fever, headache, general malaise, weight loss and night sweats with one-month evolution, previously medicated with antibiotics without improvement. She presented with sinus palpation tenderness and lower leg bilateral sensitivity impairment. Laboratory tests showed neutrophilia and eosinophilia, normocytic anemia and elevated erythrocyte sedimentation rate and C-reactive protein. A computed tomography revealed sphenoid and maxillary sinusitis. Blood cultures and lumbar puncture were innocent. An extended autoimmune panel exposed a strong positive perinuclear anti-neutrophil cytoplasmic antibody - myeloperoxidase (pANCA-MPO). Sinus biopsy showed tissue infiltration by eosinophils, confirming EGPA. Corticosteroid (1 mg/kg/day) treatment was started with gradual improvement. Six months later there were no signs of active disease under prednisolone 10 mg and azathioprine 50 mg/day. This case highlights that refractory sinusitis in the presence of constitutional syndrome and peripheral eosinophilia should alert clinicians to the possibility of EGPA, particularly in patients with late-onset asthma.