We are getting ready to go on vacation! My 9-month old gets a lot of ear infections. Should I take any kind of medication with me to prevent swimmer's ear? What type of SPF lotion should I use (he has an olive complexion)?

Dr. Greene: Your questions are timely ones for our readers in the Northern Hemisphere -- it's time for fun in the sun and the water! My apologies to those of you from Brazil, Australia, South Africa, and other countries that are heading into the winter months. But wherever you are, if you are a summer lover, take comfort in knowing that this information will be useful to you – in a few months.

Swimmer's ear is an infection of the skin lining the ear canal. Bacteria normally live on the surface of this skin with no ill effect. If there is a break in the skin's normal barrier, however, the bacteria can get inside and cause an infection called external otitis or swimmer's ear (this is different from otitis media). If the ear is wet for a long period of time, the skin can become prune-like in the same way one's fingers and toes become soft and wrinkled when they are in water for a long period of time. Bacteria can easily move into the soft skin. Tiny scratches in the ear canal (usually from sticking a finger or some other object into the ear) also leave the skin vulnerable to infection. The skin can even be breached as a result of the ear's becoming extraordinarily dry, causing the skin to crack. Ironically, swimmer's ear can be the result of spending time in desert conditions.

Swimmer's ear is more common in people who spend time in swimming pools than in people who swim in lakes. This is thought to be the case because the chlorine in swimming pools kills the good bacteria in the ear fairly effectively, but is not as effective against the harmful bacteria hiding in the ear canal. This does not mean the water in the swimming pool is infected -- the wetness is the problem. For unclear reasons, swimmer's ear is not common in infants, but it is particularly prevalent in pre-school and school-age children.

There are a couple of ways to prevent swimmer's ear. One is to make sure the ears get dry after being in the water. This can be facilitated by turning the head and gently pulling the ear in different directions to help drain the water out of the ear. It is also very helpful to dry the opening of the ear very carefully as far as you can reach with a towel. Avoid using cotton-tip applicators in the ear. If swimmer's ear becomes a recurrent problem, you can put a few drops of rubbing alcohol in each time it becomes wet, to facilitate drying. Another good alternative is instilling a few drops of white vinegar. The acetic acid inhibits the growth of bacteria in the skin.

The symptoms of swimmer's ear are itchy and/or painful ear. This is often accompanied by a small amount of clear discharge. The ear is particularly sensitive to the ear lobe's being moved up and down. If a child does develop swimmer's ear, it can often be treated with a few drops of white vinegar placed in both ears. Put the vinegar in one ear and leave it for about five minutes before turning that ear down in order to drain the vinegar solution. Repeat this twice a day for three days. If the symptoms worsen or persist for over three days, prescription antibiotic drops may be necessary.

Swimming is generally not associated with the other type of ear infections -- otitis media.