External Ear Infections - Otitis Externa

The ear is divided into three parts: the outer ear (the pinna and external ear canal), middle ear (behind the ear drum) and inner ear (cochlea). Infections of the outer and middle ear are much more common than inner ear infections.

External Ear Infections: Otitis Externa

An infection affecting the external ear canal is called otitis externa, commonly known as ‘swimmer’s ear’. Anyone can get otitis externa.

• An itchy and/or painful ear with foul-smelling fluid discharge from the ear.
• Hearing is often affected and you may complain of your ears being blocked.
• The skin of the external ear will be red and swollen and extremely sensitive to touch.

The ear has a self-cleansing mechanism and clearing of wax with cotton-tips or any tools is unnecessary. Ear wax also has anti-bacteria properties that help to prevent ear infection.

If you swim regularly, it is important to make sure the ears are dried after a swim. Turning the head and gently pulling the ear in different directions helps to drain the water out of the ear.

Gentle use of cotton-tips may be necessary but it is not advisable to vigorously clean the ear. Ear plugs can be used to prevent water from getting into the external ear canal.

You can also prevent water from entering the ear canal in the shower by plugging the outside ear with a piece of cotton wool that is slightly soaked with baby oil.

Causes of external ear infections - Otitis Externa

The skin of the ear canal is normally protected by a waxy, water-resistant coating.

• Bacteria living on the surface of the skin can cause otitis externa when there is a break in the skin’s barrier. Trauma to the skin of the ear canal from cotton-tips or finger nails can result in a break in the barrier. Someone who swims frequently is also predisposed to external ear infection. Prolonged exposure to moisture results in the water-resistant coating and skin becoming soft, allowing bacteria to infect the skin.
• High humidity in tropical countries, like Singapore, ups the risk for external ear infections.
• Diabetics are at higher risk due to poor immunity. They are also more prone to an aggressive form of infection called malignant otitis externa, in which the infection involves the skull bone.

Otitis externa can be diagnosed from history and/or a physical exam. Cultures of the fluid or swabs of the ear may be necessary to identify the specific bacteria and the antibiotics that are active against it.

Occasionally, when the offending agent is a fungus, the infection is called Otomycosis. Spores and hyphae (an element of fungus) can be seen in the external ear canal.

You can be treated by your family doctor with antibiotic ear drops. Occasionally, ear toilet by a specialist ENT surgeon is necessary. The ENT surgeon may insert an ear wick into the ear to allow the topical antibiotics to reach the deeper part of the ear canal. Some prescription drops may contain topical steroids which can help to rapidly reduce pain and swelling in the ear. Sometimes, oral pain medicines are necessary.

In patients with diabetes mellitus, intravenous antibiotics may be necessary for malignant otitis externa.