What is otitis externa?

Otitis externa refers specifically to an infection or inflammation of the outer ear canal, which is the part of the ear that runs from the outer ear to the eardrum. This condition is often colloquially known as "swimmer's ear" because it can occur when water remains in the ear canal, creating a moist environment conducive to bacterial or fungal growth.

When we consider the other options, a middle ear infection pertains to otitis media, which affects the space behind the eardrum, while an inner ear infection affects structures deeper within the ear, responsible for hearing and balance. Eardrum perforation refers to a hole in the tympanic membrane, which may occur due to various causes, including infections, but it is not synonymous with otitis externa. Therefore, the correct answer accurately reflects the specific area and type of infection involved when diagnosing otitis externa.