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The Answer is in the Solution

By Edward Thalmann, M.D., DAN Associate Medical Director

The diving has been great all week. Now, while sitting in your room, you notice that one of your ears itches and feels wet. You look in the mirror and don't see any problem, so you go to bed. Next morning when you wake up, you feel a fullness in your ear and a twinge of pain. What a time for an earache! You wonder if you should cancel the day's diving.

Your problem is probably otitis externa, a fancy name for an external ear infection sometimes called swimmers ear. As the name implies, it's usually associated with someone who swims a lot - and divers certainly fit that bill on dive-intensive scuba holidays.

The Cause
Despite what most people believe, otitis externa is not caused by bacteria in the water: instead, it's triggered by the bacteria normally found in your external ear canal. Here's how these normally innocuous bacteria can become troublesome.

With frequent immersion, water swells the cells lining the ear canal. Eventually, these cells pull apart - far enough for the bacteria normally found on the surface of your ear canal to get underneath the skin, where they find a nice warm environment and start to multiply.

Next thing you know, your ear canal itches, is sore and becomes inflamed. If left untreated, the swelling can spread to the nearby lymph nodes and cause enough pain that moving your jaw becomes uncomfortable. At this point, the only treatment is antibiotics, and diving is definitely out.

Some History
When I first entered the Navy in 1972, I was asked to look into the problem of ear infections in saturation divers. These divers spend up to a month in diving chambers aboard ships, where they are kept at the same depth as the job they are performing in the sea, whether it's salvaging a sunken vessel or performing a research project.

Each day these divers are transferred from the chamber to the work site in a diving bell. The divers spend a great deal of their time immersed. Both the chamber and the bell provide a hot, humid environment, perfect for breaking down the cellular lining of the ear canal; and the result is often otitis externa.

Prevention
Otitis externa was so prevalent at the time I entered the Navy that up to 20 percent of all saturation divers were expected to get it. I searched the medical literature and found an article that had the answer: instructors at a summer camp found that dripping an acidic drying solution into the ear at the beginning and end of each day virtually eliminated swimmer's ear in their young charges. The trick, however, was that the solution had to remain in each canal a full five minutes. If this part of the treatment was ignored, ear infections soon reappeared.

To treat the Navy divers I decided to use Otic Domeboro®* Solution: 2 percent acetic acid, water, aluminum acetate, sodium acetate and boric acid. The acid retards bacterial growth, while the aluminum and sodium acetate act as astringents, drawing excess water out of the cells lining the ear canal. We had the divers put this solution in each ear canal twice a day and hold the solutions for at least five minutes at a time, timing them from outside the chamber.

The result? Otitis externa is no longer a problem in Navy saturation divers, and the above external ear prophylaxis remains a standard part of U.S. Navy Saturation diving procedure to this day. It's useful for sport diving, too, when there are frequent dives over several days.

Using the Solution
The only problem for sport divers is that Otic Domeboro Solution is a prescription drug, so you'll need to get it through a doctor. (Note: Bausch & Lomb and Qualtest make similar products.) And it's not cheap: a 2-ounce bottle costs in the neighborhood of $25. But that bottle should easily be enough for 60 or more days of use.

There are other preparations available over the counter (Auro-Dri, Swim-Ear) that are less expensive and consist of 95 percent isopropyl alcohol, with anhydrous glycerine. These preparations will certainly take care of drawing excess water out of the cells, but their lack of acidity makes them less powerful at inhibiting bacterial growth. Unfortunately, none of these over-the-counter preparations has been tested in the diving environment, so whether they will work as well as Otic Domeboro Solution is unknown.

Whatever preparation you choose to use, the trick is in the application. Before your first dive in the morning and after your last dive each night, here's what to do:

The head is tilted to one side and the external ear canal gently filled with the solution, which must remain in the canal for five minutes. The head is then tilted to the other side, the solution allowed to run out, and the procedure repeated for the other ear. The five-minute duration must be timed with a watch. If the solution does not remain in the ear a full five minutes, the effectiveness of the procedure is greatly reduced.
- From the U.S. Navy Diving Manual

Remember, this is a prophylactic procedure that should be started before the ear becomes infected - beginning it only after an infection occurs will not help much. One word of warning: Do not put drops in your ear if you have any reason to suspect you may have a ruptured eardrum from a squeeze. If you do, you may wash bacteria into the middle ear, where an infection can be really bad news.

Clearing That Waxy Buildup
If you're diving for an extended period of time, the cerumen in your ear may build up and cause the external ear canal to become blocked off. Once this happens, it greatly reduces the effectiveness of the external ear prophylaxis and makes an infection much more likely.

If you think your ear canal is blocked, the best way to find out is to have someone who is trained to use an otoscope use one to look in your ear. If the eardrum isn't visible, the excess cerumen should be removed. Don't use swabs or other instruments to remove cerumen. Gently flushing the canal with water while in the shower, with hydrogen peroxide, or by using commercial over-the-counter solutions designed to remove earwax are the best bet. If that doesn't work, see a doctor to have the wax removed. Any intrusion into the ear canal should be done by trained medical personnel only.

For preventive measures, one way to prevent the buildup of cerumen (earwax) is to gently flush the ear canal when showering: Cup your hand next to your ear, and let your hand fill with water, which will overflow into the ear canal. Don't let the shower stream enter your ear directly, though; it could damage your eardrum or hearing.

For more details, see More on Swimmers Ear.