A 58-year-old man was admitted after an episode of purpuric skin eruption with blisters and ulcers, pain, and paresthesia of bilateral lower limbs. He had a 12-year history of asthma and was diagnosed with eosinophilic chronic rhinosinusitis (ECRS) at the age of 40. Four weeks prior to admission, the patient was diagnosed with eosinophilic pneumonia due to increased blood eosinophil counts (13,680/muL) and ground-glass shadows on chest radiograph and computed tomography (CT) (Fig. 1). His serum total immunoglobulin (Ig)E was 2,080 IU/mL. Aspergillus serology blood test revealed negative results. The results of chemiluminescent enzyme immunoassay testing showed a slight increase in the levels of myeloperoxidase anti:neutrophil cytoplasmic antibody (MPO-ANCA) (10.8 IU/ml; normal reference: < 3.5 U/ml). At age of 47, his left lung was removed due to bronchial tuberculosis. Therefore, he initially refused to take steroids, fearing tuberculosis relapse. The patient was treated for eosinophilic pneumonia with benralizumab (30mg administered subcutaneously) alone instead of corticosteroids. After treatment with benralizumab, the eosinophil count decreased from 13,680/muL to 2,450/muL at one week, to 110/muL at two weeks, and then increased again to 760/muL at three weeks. One week after benralizumab administration, pain appeared in the lower extremities, followed by numbness in the lower extremities at two weeks later. Moreover, three weeks after benralizumab administration, skin rash with ulceration occurred, resulting in hospitalization. The MPO-ANCA level had increased to 130 IU/ml. A skin biopsy of lower limb purpura revealed fibrinoid necrotic vasculitis of the superficial blood vessels, along with nuclear dust and perivascular eosinophilic dermatitis with neutrophil and granulomatous inflammation (Fig. 2). Since all six of the American College of Rheumatology (ACR)/European Alliance of Associations for Rheumatology (EULAR) classification criteria were met, the patient was diagnosed with EGPA. These criteria include: asthma, chronic rhinosinusitis, eosinophilia >10%, transient pulmonary opacities, polyneuropathy and extravascular eosinophils on histology. Prednisone treatment (60 mg daily) was initiated. The patient's symptoms rapidly improved. In addition, the prednisone dosage was gradually tapered. Written informed consent was obtained from the patient for the publication of this report.