Dermatologic diseases of the external auditory canal.

The external auditory canal is the only cul-de-sac lined with skin in the human body. Accordingly, most diseases of the external auditory canal, including infections and tumors, could rightly be considered dermatologic. This article, however, discusses only the involvement of the canal by primary dermatologic conditions that typically have a more general distribution as well as local dermatologic reactions to environmental insults.