Swimmer’s ear is an infection of the outer ear canal that is usually caused by bacteria. The official name of the infection is “otitis externa,” but it’s usually called swimmer’s ear because it so often occurs in swimmers.

You’ve probably experienced itching and redness in and around the ear. You may have had yellow, green or even cheesy drainage from the ear. You may have felt pain when you touched your ear or when you chewed or talked. If the ear canal was very swollen, you may have had some trouble hearing.

Normally, the skin inside your ear canal is dry. When you swim, the skin inside your ear canal stays wet. It gets white and puffy.

The function of skin is to serve as a barrier against infectious organisms: It is a wall that keeps them outside us. When it gets and stays wet for a while, the wall weakens. Bacteria get through and underneath the skin.

When the skin of the ear canal is weakened by water, bacteria can start to invade. That can cause itching. If you scratch the itch inside your ear, that can injure the skin and make it easier for the infection to worsen.

Prescription eardrops contain medicines to counter infection and inflammation. With treatment, symptoms usually improve within 24 hours and go away in two or three days.

To help prevent swimmer’s ear:

If you get water in your ears, dry them thoroughly. First, turn your head to the side and pull the earlobe in different directions to help the water run out. Gently dry the opening to the ear canal. Then use a hair dryer briefly on its lowest setting held at arm’s length to dry the rest of the canal.

Do not use cotton swabs to clean your ears. Swabs can cause trauma to ear canals.

Do not use earplugs unless they are designed specifically to keep water out.

Eardrops after swimming can reduce your risk of getting swimmer’s ear. You can buy non-prescription eardrops at the drugstore. You can make a similar “home-grown” remedy by mixing equal parts white vinegar and rubbing alcohol. Use three to four drops in each ear after swimming.