Swimmer's ear, also known as otitis externa, is an inflammation of the outer ear canal. Although it is most prevalent among young adults and children, who often contract the condition from frequent swimming, swimmer's ear can affect anyone.
Swimmer's ear is an inflammation of the outer ear that may lead to a painful and often itchy infection. It begins with the accumulation of excess moisture from swimming or daily showering. The skin inside the ear canal may flake due to moisture. This flaking may cause persistent itching that may lead to a break in the skin from scratching. Broken skin allows bacteria or a fungus to infect the tissues lining the ear canal. Swimming in polluted water can easily bring harmful bacteria into the outer ear.
In swimmer's ear, the patient nearly always has a history of recent exposure to water combined with mild injury to the skin of the inner ear. This injury is typically caused by scratching or excessive and improper attempts to clean wax from the ears. Wax is one of the best defense mechanisms the ear has against infection due to the protection it offers from excess moisture and the environment it provides for friendly bacteria. Earwax should not be removed by such sharp objects as fingernails or hairpins. If the wax is scratched away, it becomes easier for an infection to occur.
The infection itself is usually caused by gram-negative bacilli (Pseudomonas aeruginosa or Proteus) or by fungi (Aspergillus) or even yeasts that thrive in moist environments. There are a surprisingly large number of different organisms that can cause otitis externa; one study of 2039 patients diagnosed with swimmer's ear found that 202 different species of bacteria, 32 species of yeast, and 17 species of mold could be identified as the infectious agents in this group of patients.
In recent years, some of the organisms most likely to cause otitis externa have developed resistance to antibiotics; the resistant organisms vary from country to country. One Asian study found that Staphylococcus aureus is responsible for more cases of swimmer's ear in East Asia than Pseudomonas aeruginosa, and that methicillin-resistant S. aureus, or MRSA, is an increasingly worrisome problem in these countries. A study done in Texas, however, found that Staphylococcus epidermidis was responsible for the largest number of antibiotic-resistant cases.
In a minority of cases, otitis externa is caused by an allergic reaction. The most common allergens in chronic otitis externa are topical medications used in the ear, particularly preparations containing neomycin; nickel and other metals used in inexpensive earrings; and some materials used to make hearing aids.
Beth Kapes, Rebecca J. Frey PhD, The Gale Group Inc., Gale, Detroit,