Otitis externa Dr Trisha Macnair Otitis externa is commonly referred to as swimmer’s ear.

In this article

What is otitis externa? Symptoms

Causes and risk factors Treatment and recovery

Otitis externa is an inflammation of the outer ear canal - the tube between the skin surface of the external ear and the ear drum.

There's redness and swelling of the skin of the ear canal. It may be itchy (especially in the early stages) and can become sore and painful. There may be a discharge, or increased amounts of ear wax. If the canal becomes blocked by swelling or secretions, hearing can be affected.

Otitis externa is usually caused by an infection, which may be fungal or bacterial. A bacterial infection is more likely to result in a localised problem, such as an inflamed spot or boil in the ear canal, but can cause cellulitis or more widespread inflammation of the tissues.

Fungal otitis externa usually causes a more diffuse irritation of the skin. Otitis externa may also develop in skin conditions such as eczema or dermatitis, where there's no infection but generalised inflammation of the skin.

Anyone can develop otitis externa. It can follow localised trauma to the skin of the ear canal - for example, if objects are placed in the ear - or if the canal is scraped by a cotton tipped bud in an attempt to remove wax (cerumen to give it its technical name) which plays an important protective role - too little may predispose to infection, although too much causes retention of water in the ear canal, which can allow bacteria to thrive.

Constantly getting the ears wet can damage the normal immune defences in the ear leading to infection (hence swimmer's ear). People with diabetes are at increased risk of infections, especially of the skin.

The ear must be examined using an instrument called an otoscope, and a swab taken to test in the laboratory for bacteria or fungi. Cleaning the ear and removal of discharge, using gentle suction, may be all that's needed in very mild cases to allow the body to clear the infection.

Most cases are usually treated with antibiotics, usually as ear drops. Occasionally, in more severe or recurrent otitis externa, antibiotics must be given by mouth. Steroid cream or drops may also be given.

In most cases, symptoms resolve with treatment within two to three days. Occasionally, more often in diabetics, the infection spreads to surrounding tissue and intravenous antibiotics are needed. Some people who experience recurrent episodes of otitis externa may benefit from the use of acidifying ear drops after every exposure to water (such as showers and swimming).

This article was last medically reviewed by Dr Trisha Macnair in May 2009.