Infective otitis externa is a painful, sometimes itchy infection of the outer ear canal.

The outer ear canal is the short passage from the outside of the ear to the ear drum, which is an inch or so inside. Infection causes swelling, redness, heat and pain (inflammation), and is often associated with a discharge that contains white blood cells. These form part of the body's defence mechanisms.

There is sometimes a slight itch with discomfort, while there can be severe pain. Temporary deafness often results, as swelling and discharge may block the ear canal, and swelling may affect the ear drum itself.

The cause is a germ infecting the outer ear canal. Most often this is caused by bacteria (which can be treated with antibiotics), but sometimes other causes, such as fungus infection, are to blame.

The infection can happen to anyone. Sometimes a cause can be traced, such as swimming in infected sea water (many surfers will attest to this). Most times it is not possible to be sure why it started.

Some people seem to have one episode after another. It may be that some of these people have a habit of fiddling with or picking at their ears, and introduce the infection themselves, inadvertently.

Just touching the outer ear can be painful. Your doctor can usually tell all he or she needs to from looking in your ear. Sometimes a specimen is taken by wiping a swab just inside the ear, and this is sent to the laboratory to find out which germ is involved.

Most times your family doctor will treat the infection with either ear drops (which usually contain an antibiotic or antiseptic, along with some steroid), or a course of antibiotics. On occasion you may be given both drops and antibiotics.

If the pain is bad you may need to take pain killers (analgesics) such as paracetamol or anti inflammatory drugs in addition. Usually the infection settles quite quickly.

Sometimes the ear canal needs more attention. This may involve seeing a specialist, and perhaps having the ear cleaned out or a dressing inserted temporarily.