A history of swimming or diving or of repetitive ear cleansing with soapy water and cotton-tipped swabs often is elicited. Most patients are seen for evaluation of ear pain, itching, and fullness. Pain is exacerbated by manipulation of the pinna or tragus, a feature useful in differentiating between otitis externa and otitis media. Purulent discharge may be present in the external auditory canal. The canal walls are diffusely erythematous and edematous. Ipsilateral cervical lymph node enlargement may be noted, but usually fever is absent.

Otitis externa is a clinical diagnosis. The historical features and physical findings are sufficiently characteristic so most patients present no real diagnostic dilemma. Conversely, several other
conditions mimic external otitis in some cases. Furunculosis is, in a sense, a focal form of otitis externa. Symptoms and signs resemble those of the diffuse condition, but otoscopy reveals a discrete furuncle or pustule with surrounding erythema in the outer portion of the external auditory canal. Otitis media causes ear pain that is not exacerbated by manipulation of the pinna. Usually, perforation of the tympanic membrane results in symptomatic improvement, although the external canal may fill with purulent debris. Cleansing the canal permits otoscopic detection of the perforated tympanic membrane. A foreign body, usually visible in the external canal, may cause inflammation and discharge closely mimicking diffuse external otitis.