Otitis externa is an infection of which part of the ear?

• A. Inner ear
• B. Middle ear
• C. Eardrum
• D. Outer ear

Answer: (D)

Otitis externa is infection of the outer ear—the part you see and feel, including the ear canal (external auditory canal) and surrounding skin. This region is more exposed to moisture and irritants, which is why infections called swimmer’s ear are common after swimming or when the ear canal remains damp. Symptoms typically include itching, redness, swelling in the ear canal, and sometimes discharge.

This is different from infections in the middle ear or inner ear. The eardrum (tympanic membrane) marks the boundary between the outer and middle ear, so an infection involving the eardrum is categorized with middle-ear problems rather than the outer ear. Understanding the location helps explain why the treatment focuses on the external canal with topical agents and keeping the ear dry.