Otitis externa: a practical guide to treatment and prevention.

Otitis externa is most commonly caused by infection (usually bacterial, although occasionally fungal), but it may also be associated with a variety of noninfectious systemic or local dermatologic processes. The most characteristic symptom is discomfort that is limited to the external auditory canal, while the most characteristic signs are erythema and swelling of the canal with variable discharge. Excessive moisture and trauma, both of which impair the canal's natural defenses, are the two most common precipitants of otitis externa, and avoidance of these precipitants is the cornerstone of prevention. Thorough cleansing of the canal is essential for diagnosis and treatment, but flushing should be avoided. Acidification with a topical solution of 2 percent acetic acid combined with hydrocortisone for inflammation is effective treatment in most cases and, when used after exposure to moisture, is an excellent prophylactic. Other prophylactic measures such as drying the ears with a hair dryer and avoiding manipulation of the external auditory canal may help prevent recurrence.