The best way to prevent otitis externa is to keep the ear canal dry. After a bath or shower, gently wipe the ear with a towel. Frequent swimmers should use a drying agent — such as hydrogen peroxide or rubbing alcohol — after swimming. Earplugs worn during swimming do not seem to reduce the risk of otitis externa.

If your child has otitis externa, some data suggest that acetic acid (vinegar) drops help reduce bacteria in the canal. The recommended regimen is five drops of acetic acid given three times a day for one week. This may be a reasonable thing to try, but if the symptoms get worse, or if your child does not improve with the drops, you should contact your doctor.

There are also many swimmer’s ear drops sold over the counter.

When does my doctor need to be involved?
Call your doctor if the ear appears red or if liquid is draining from the canal. If your child is in significant pain anytime the ear is touched, let your doctor know.

If your child has symptoms of otitis externa along with a fever, you should call your doctor, as the two don’t generally go together.

What tests need to be done, and what do the results mean?
Most of the time, tests are unnecessary with otitis externa. However, if the condition becomes chronic, or if it fails to improve with treatment, a culture may be performed. This can help determine precisely what type of bacteria is causing the problem and what antibiotic will be most effective.

The culture is very easy to do: a sterile Q-Tip-like device is used to swab the lining of the canal. But it is usually not that important to do a culture to determine precisely what kind of bacteria is causing the infection. Remember that bacteria normally inhabit the skin, including the skin in the ear canal. Therefore, when a sample is taken, the results often show normal skin bacteria. This is not very helpful in determining a course of action, because it can be very hard to tell whether the normal bacteria are contaminating the culture (masking the true source of the infection) or they have actually infected the ear canal. Normal bacteria can cause otitis externa, but almost all antibiotic treatments used for otitis externa are effective against these bacteria. If your child is started on antibiotics, you can be fairly certain that the medicine will treat an infection caused by the bacteria it normally live on the skin. So unless the ear continues to get worse despite treatment, a culture usually is not needed.