A diagnosis of CSS was made on the basis of bronchial asthma, neuropathy of the peroneal nerve and ulnar nerve, findings of angiitis by biopsy of the left sural nerve, increased eosinophil counts, and positivity for myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA). Here, MPO is linked to eosinophilic granulomatosis with polyangiitis.