Negative anti-neutrophil cytoplasmic antibodies and eosinophilic granulomatosis with polyangiitis accompanied by cough variant asthma: a case report.

Eosinophilic granulomatosis with polyangiitis (EGPA), formerly called Churg-Strauss syndrome, is a rare chronic necrotizing eosinophilic granulomatous inflammatory disease characterized by eosinophil-rich granulomatous inflammation and small- to medium-size vessel vasculitis associated with bronchial asthma and eosinophilia, which is positive for anti-neutrophil cytoplasmic antibody (ANCA) in approximately 50-70% of cases. We report a case of a 23-year-old woman was admitted to our hospital because of a of small vesicles on both lower limbs and a 4-month history of small scattered skin rash with pruritus V6 on both lower limbs four-month history of scattered skin rash with pruritus. Laboratory data from peripheral blood revealed leukocytosis, eosinophilia, thrombocytosis, hyperfibrinolysis, and mild renal injury. Her ANCA was negative, and the skin pathological examination showed granuloma lesions with eosinophils, while elevated eosinophils were also found in the bone marrow. EGPA was diagnosed. On the other hand, the patient had 2-year-long rhinosinusitis, 9-month-long nephrotic syndrome, and 1-month-long dry cough, which might be a type of asthma. With steroid therapy followed by systemic immunomodulatory therapy, the patient's symptoms were relieved. Our case report and literature review highlight the importance of recognizing cough variant asthma as an initial presenting symptom of EGPA, providing an opportunity for early diagnosis and treatment to reduce the risk of further disease progression and morbidity.