慢性外耳炎（COE）是由外耳道（EAC）或耳廓的红斑、瘦痒性皮炎脱屑引起的，病人常述有耳部懂痒和由于EAC水肿或脱屑而继发的传导性耳聋。多数病例可以通过清洁EAC，偶尔用抗生素滴耳液治愈。但有些病例则很顽固，持续多年久治不愈，此时需做鉴别诊断，包括EAC癌、皮蛆病、牛皮 Chronic otitis externa (COE) is caused by the erythema of the external auditory meatus (EAC) or the pinna, pruritus dermatitis, and patients with pruritus and conductive deafness secondary to EAC edema or desquamation. Most cases can be cleaned EAC, and occasionally cured with antibiotic ear drops. However, some cases are very stubborn, persist for many years, when the need for differential diagnosis, including EAC cancer, myiasis, leather