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