The medical term for an ear discharge is otorrhoea. An ear may discharge wax, blood, pus, serum (the pale yellow liquid part of blood without the cells) or cerebrospinal fluid (CSF – the fluid that surrounds and supports the brain).
The most common substance to be discharged is wax, and if a patient has a fever, the higher temperature may melt the wax in the ear canal, allowing it to flow out more easily than normal.
If there is a foreign body in the ear canal (e.g. a small toy, nut, insect), the irritation may cause pain, bleeding, dermatitis (and a watery discharge of serum) and infection with pus formation.
Otitis externa (swimmer’s ear) is a bacterial or fungal (tropical ear) infection of the ear canal. The ear becomes very painful, and as the infection progresses, a smelly discharge usually develops.
Middle ear infections (otitis media) are a very common cause of temporary deafness in children that if left untreated, may progress to a permanent partial loss of hearing. The ear is painful, the child is feverish and when a doctor examines the ear, a red bulging eardrum can be seen. If the drum bursts pus will discharge from the ear, but the pain will diminish.
Other causes include a furuncle (a boil in the ear), weeping dermatitis or eczema in the ear canal, a severe head injury in which the skull around the ear is fractured (some of the cerebrospinal fluid that surrounds and supports the brain may leak into the ear canal) and rarely, tumours or cancers in the ear canal will discharge and bleed.