On a humid afternoon following a hot hike, a plunge in the lake is irresistible. But beware, water sometimes gets trapped in the ear canal, causing it to become swollen and wrinkly. With that water come bacteria and fungi, which take up residence in your ear and cause infection (swimmer's ear). The swollen canal hurts, sometimes to miserable extremes, and your ear may feel blocked. To test for swimmer's ear, tug lightly on the outer ear; if you feel pain in the canal, you have it.
To treat the problem, try irrigation; it usually works, and may be your only option in the wilderness. With your head tilted so the affected ear is toward the ground, gently flush the canal with warm treated or filtered water in a small squeeze bottle, such as those used for eyedrops or saline solution. Even better is a solution of 4 parts water to 1 part alcohol or vinegar. Don't plunge objects, such as cotton swabs, into an ear canal. They abrade the surface, making matters worse. Irrigate three or four times daily until the pain subsides. Between treatments, keep your ear dry.
If your ear canal is too swollen to permit irrigation, hike out and find a physician. Over-the-counter painkillers offer some relief of symptoms. If you know you're susceptible to ear infections, flush your ear with the water and alcohol or vinegar solution after swimming.