Acute otitis externa (AOE), known as “swimmer’s ear,” is a common problem encountered in emergency medicine practice, especially in the summer months. As a conservative estimate, 2.4 million U.S. health care visits result in a diagnosis of AOE annually (8.1 visits/1,000 population), affecting at least 1 in 123 persons each year. In 2007, 1 in 324 emergency department visits and 1 in 481 ambulatory care clinic visits resulted in a diagnosis of AOE. Although the illness is usually relatively mild, patients might be prevented from attending school, work, or social activities.

AOE can be costly, too. Nonhospitalized visits for AOE cost more than $489 million in direct health care costs. Also, in 2004, an estimated $310 million was spent on ototopical medicines.1 These figures do not include the additional costs of lost wages at work, school absence, lost social opportunities, and in the worst cases, inpatient care.

A median of 15 minutes is spent per patient diagnosing and treating AOE in the outpatient setting. Ambulatory health care providers expend an estimated 598,000 hours on patients with AOE annually. A few simple messages passed along to patients and their parents at the first encounter might help reduce the overall burden of AOE.

AOE is inflammation of the outer ear canal characterized by redness, swelling, pruritis, occasional exudate, and pain that is aggravated when the pinna is moved. The vast majority of AOE is caused by bacteria.^1,2 The most common bacterial pathogens cultured from infected ear canals include Pseudomonas aeruginosa and Staphylococcus species.^2-4 Factors that predispose the ear to infection include increased environmental temperature, high humidity, and water exposure, especially swimming.^1,5,6

Exposure of the skin of the ear canal to water, particularly prolonged exposure, can lead to maceration of the skin, making the ear more vulnerable to minor trauma and infection. Minor trauma could be caused by anything inserted in the macerated ear canal such as cotton-tip swabs,⁷ hearing aids, other foreign objects, or even one’s own finger when scratching itchy ears.^1,8,9 Water exposure can also wash away protective cerumen, the waxy ear substance that serves as a water-repellent coating for the skin of the canal and has antimicrobial properties.¹⁰

Studies have shown that AOE is more likely to occur among swimmers.^3,5,11-13 The longer swimmers are in the water and the more frequently they submerge their head, the greater the risk of developing AOE.^12-14 Some studies found that frequent showering or bathing increased risk,¹² although others did not.^3,5 Soaps, shampoos, and chlorine from pool water might irritate the skin of the external auditory canal and also contribute to the loss of protective cerumen.¹⁵