Otitis Externa - Diagnosis

Diagnosis

When the ear is inspected, the canal appears red and swollen in well-developed cases. The ear canal may also appear eczema-like, with scaly shedding of skin. Touching or moving the outer ear increases the pain, and this maneuvre on physical exam is important in establishing the clinical diagnosis. It may be difficult to see the eardrum with an otoscope at the initial examination because of narrowing of the ear canal from inflammation and the presence of drainage and debris. Sometimes the diagnosis of external otitis is presumptive and return visits are required to fully examine the ear. Culture of the drainage may identify the bacteria or fungus causing infection, but is not part of the routine diagnostic evaluation. In severe cases of external otitis, there may be swelling of the lymph node(s) directly beneath the ear.

The diagnosis may be missed in most early cases because the examination of the ear, with the exception of pain with manipulation, is nearly normal. In some early cases, the most striking visual finding is the lack of cerumen. As a moderate or severe case of external otitis resolves, weeks may be required before the ear canal again shows a normal amount of cerumen.