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

Because AOE is more likely to occur among swimmers and in warm, humid environments, it is not surprising that AOE peaks in the summer months (more than 44% of visits for AOE occur from June through August). Also, rates of AOE are higher in the humid Southeast (9.1/1,000 population), compared with other regions of the United States (see map). With increasing use of indoor recreational water facilities, however, it is not surprising to encounter AOE year round.

AOE is found among patients of all ages. The highest rates occur in 5- to 9-year-olds, but more than half of cases occur among adults (see table, p. 27). Once diagnosed with AOE, approximately 3.6% of ambulatory care patients are referred to another provider for additional care, and approximately 2.7% of all patients seen in the emergency department with AOE are admitted to the hospital.

Recent systematic reviews of treatment options for AOE have determined that topical treatment is highly effective.^16-18 Topical antimicrobials either alone or in combination with a corticosteroid are superior to placebo; cure rates are comparable between topical combination drops and topical antimicrobials alone.17 More research is needed to determine if topical corticosteroids alone are effective.¹⁶

For straightforward cases of AOE that do not involve cellulitis, necrotizing otitis externa, or other complicating factors (e.g., diabetes or immuno­­suppression), there does not appear to be any advantage to administering systemic antimicrobials.1,18 Addition of oral antibiotics will not improve symptoms, compared with using topical agents alone.^1,18

Instruct patients to use the drops for at least a week, continuing use for a few days after symptoms resolve. Most patients have resolution of symptoms by 6 days after starting treatment.16 If no improvement is noted in 48-72 hours, or if symptoms persist beyond 2 weeks, consider switching to a different agent.^1,16

Patients with AOE should avoid submerging their heads in water for 7-10 days, but competitive swimmers might be able to return to the pool if pain has resolved and they use well-fitting ear plugs.¹

Although AOE readily responds to appropriate treatment, it is a disease that can be prevented by some simple measures. So what do you tell families about preventing AOE? Addressing the subject at the first encounter might head off more visits later in the summer swim season and help ensure that kids won’t have to miss out on all the summer fun. The literature is sadly lacking in scientific studies on preventive measures, so we rely instead on reducing established predisposing factors.^1,16,18

Strategies for preventing AOE involve limiting water content in the ear canal and maintaining a barrier of healthy skin (see sidebar, p. 26). Keeping ears as dry as possible is important in both treating and preventing AOE. Tell your patients to dry their ears thoroughly after swimming or bathing. Use a towel to dry the ear, tilt the head to each side in turn to allow water to drain from the down-turned ear, and consider using a blow dryer set on the lowest heat and fan speed held several inches away from the ear.^{6,8,9,16,19-21}

Some sources recommend using alcohol-based ear drops after swimming (or each morning and evening) to reduce moisture content in the ear canal, correct the ear pH, and reduce bacterial growth.^9,16,19-24 Commercially prepared, alcohol-based ear-drying solutions are available, or patients can make their own 1:1 mixture of rubbing alcohol and white vinegar. Note that these drops should not be used in the presence of ear tubes, perforated tympanic membranes, or acute external ear infection.

Instruct patients and parents to avoid putting objects into the ear canal, even if the ear feels moist, itchy, or blocked with cerumen. Nothing should be put into the ears, including fingers or cotton-tip swabs.^7-10,19-21

Some research suggests using ear plugs when swimming.^{1,6,16,19,22,25} Other research indicates this might actually increase the risk of infection by traumatizing the skin.^8,9,21 Swimming caps have been suggested as an alternative way to exclude water from the ear.^8,21 However, occlusive head gear has also been associated with external ear infections.26 If any type of ear plug is to be worn, cotton wool smeared with petroleum jelly is as effective at keeping water out as more expensive devices.²⁵

Although AOE is generally a mild illness, it is a frequently diagnosed condition responsible for a substantial burden in health care dollars and clinicians’ time. Passing along a few simple messages to our patients and their families can help prevent some future cases of AOE. Swimming is a healthful activity that should be encouraged. We can help keep kids active and healthy by giving patients and their parents ideas on how to prevent future cases of swimmer’s ear.

Dr. Piercefield and coauthors are with the Centers for Disease Control and Prevention.

For further information about Recreational Water Illness and Injury Prevention Week, please visit www.cdc.gov/healthywater/swimming/rwi/rwi-prevention-week/index.html. General information about recreational water illnesses can be found at www.cdc.gov/healthywater/swimming/rwi. More information for patients on swimmer’s ear is located at www.cdc.gov/healthywater/swimming/rwi/illnesses/swimmers-ear.html.

References

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