NICE CKS Otitis externa
Otitis externa is inflammation of the external ear canal
- Localised otitis externa is a folliculitis (infection of a hair follicle) that can progress to become a furuncle (boil) in the ear canal
- Diﬀuse otitis externa (also known as swimmer’s ear, or tropical ear) is widespread inflammation of the skin and subdermis of the external ear canal, which can extend to the external ear and the tympanic membrane (ear drum)
- Otitis externa is defined as:
- acute if it has lasted for 3 weeks or less
- chronic if it has lasted for longer than 3 months
- Malignant otitis externa is an aggressive infection that predominantly aﬀects people who are immunocompromised, or have diabetes mellitus, or the elderly. Otitis externa spreads into the bone surrounding the ear canal (the mastoid and temporal bones). It is also known as necrotising otitis.