Allergic otitis externa.

Chronic otitis externa is a common condition, which is usually successfully treated by topical medications and aural toilet. In cases that persist despite conventional treatment, a diagnosis of allergic otitis externa should be considered. Sensitization to otic medications (secondary contact otitis) is not uncommon. Topical aminoglycosides are the most common sensitizers although many components of topical preparations can cause sensitization. Patients who may have developed allergic otitis externa should undergo patch testing. Otolaryngologists should consider using topical antibiotics with a low allergenic potential and avoiding neomycin when treating patients with otitis externa. Primary contact otitis may occur to metals used in earrings and also to hearing aid moulds. Treatment of both primary and secondary contact otitis consists of identifying the allergen, avoiding further contact and use of simple preparations avoiding common sensitizers.