Dermatology

Swimmer’s ear (otitis externa, infection of the external ear canal)

Swimmer’s ear (otitis externa, infection of the external ear canal) ICD-9 380.12

Are You Confident of the Diagnosis?

What you should be alert for in the history

Swimmer’s ear, more properly termed otitis externa, is a bacterial infection of the extrenal portion of the ear canal. The most frequent etiological agent responsible is Pseudomonas aeruginosa. P. aeruginosa has been found to be present in 1-2% of the normal population’s ear canals.

The disease frequently will occur within a few hours to 1 week after exposure to a water source. Therefore patients should be asked about recent water activities.

Patients with diabetes and chronically immunosuppressed individuals are at higher risk for the development of otitis externa.

Characteristic findings on physical examination

Patients will present with tenderness and pain. Itching may be the first symptom. Patients are often unable to sleep on the affected side secondary to pain. When the earlobe is manipulated the pain worsens. Pushing against the tragus will also illicit pain. A decrease in hearing acuity on the affected side is often a complaint.

When the disease has firmly taken hold, purulent, malodorous drainage is frequent. The external portions of the ear that are visible are swollen, red, warm and tender.

Ask the patient to move the mandible from one side to other. This can cause severe pain in the affected ear. Check for fever. Perform an otoscopic exam to look for involvement of the tympanic membrane (specifically rupture).

Expected results of diagnostic studies

A bacterial and fungal culture of the external ear canal should be performed. The lab should be informed you are looking for Pseudomonas.

Diagnosis confirmation

The differential diagnosis includes:

--Foreign body: Children commonly will place objects in the ear canal without the knowledge of supervising adults. Similar symptoms may occur, with pain, purulence, and swelling. Otoscopic exam will reveal the cause. Treatment is to remove the object.

--Allergic contact dermatitis: These patients typically have been using a topical agent in the ear canal for any number of reasons. The history is typically not suggestive as they do not usually have water exposure. The skin is more eczematous in nature with more itching than pain. Swelling may be severe and cause pain. If the swelling closes the ear canal, a secondary otitis externa may form.

--Ear squeeze (scuba diving associated ear pain, barotitis media): This occurs in nearly all scuba divers at some time over their diving careers. It is caused by abnormal pressure differential between the middle ear and external ear. There is no drainage or swelling, and the pain is very acute and occurs during or immediately after the dive.

Who is at Risk for Developing this Disease?

Swimmers and others who spend considerable time in water sources (scuba divers, water skiers, and other aquatic activitites) are at increased risk for developing this condition. It is more common in the summer months. There is no racial or sex predilection, and the disease appears to be most common in children aged 7-12.

What is the Cause of the Disease?

Etiology

Swimmer’s ear is caused by overgrowth of bacteria, specifically P. aeruginosa. Many other bacteria (second most common being Staphlococcous aureus) and fungi can be present and play a role in disease formation.

Pathophysiology

Moisture retention: This in turn is directly related to the amount of time one spends in water. Swimmers are 5 times more likely to develop otitis externa than non-swimmers. Factors that lead to moisture retention include: abnormalities in the anatomy of the external auditory canal, excessive buildup of cerumen, and chronic dermatoses (such as psoriasis) due to the buildup of scale which is able to retain moisture.

Temperature: The ear canal is at the perfect temperature for the growth of bacteria. The ear canal temperature is an excellent approximation of the core body temperature.

Bacteria: Bacteria are present normally within the external ear canal, and when moisture retention occurs they are able to proliferate, invade the epithelial lining of the canal and cause disease. The normal acidic nature of the ear canal (pH 4-5) inhibits bacterial growth under normal circumstances. During moisture retention, and a build up of cerumen and epithelial debris, the pH increases significantly and thus innate protection is decreased.

Swimmers are more prone to developing otitis externa as they introduce more bacteria into the ear canal along with moisture allowing for the perfect growth enviornment.

Trauma: Any damage to the lining of the ear canal can increase the likelood of developing otitis externa.

Systemic Implications and Complications

Rupture of the tympanic membrane may lead to otitis media and permanant loss of hearing acuity.

If the infection is allowed to persist, it may penetrate the underlying cartilage of the ear canal wall causing auricular cellulitis, ultimately causing facial cellulitis. This can also lead to infection within the parotid gland and a septic temporomandibular joint (TMJ).

Myringitis can occur, causing inflammation or infection of the tympanic membrane (ear drum).

Chronic cases can lead to stenosis of the external ear canal. This increases the likelihood of future development of otitis externa and can lead to permature hearing loss.

Malignant otitis externa (necrotizing external otitis), a life threatening complication, is rare; however, one must be aware of its clinical signs and symptoms due to its seriousness. Hyperbaric oxygen in conjunction with the appropriate surgical and antibiotic therapy has been shown to be helpful in cases. Malignant otitis externa is caused by an infection of the temporal bone and potentially other basilar skull bones.

P. aureginosa is the most frequent bacterial agent, and it occurs after untreated or partially treated otitis externa. Patients with poorly controlled diabetes, the elderly and those that are immunosuppressed are at greatest risk. Untreated otitis externa may invade the cartilage of the ear canal with extension into the temporal bone. Symptoms are nearly the same as with otitis externa, with the exception of severe night pain in the affected ear.

Evaluation with an otoscope is required. If one sees granulation tissue in the external auditory canal at the junction of the bone to cartilage interface the diagnosis can be made. Once the diagnosis of malignant otitis externa is considered a CT scan of the head is required. Referral to a head and neck ENT surgeon should be promptly performed. Prolonged antibiotics (based on culture and sensitivity results) with the possibility of surgical debridement is the therapy of choice. Hyperbaric oxygen has been shown to be helpful.

Treatment Options

Treatment options are summarized in the Table I.

Table I.

Treatment Options for Swimmers Ear
Medical Surgical
Decrease moisture Removal of ear canal debris after swelling is reduced, by a physician
Wicks soaked in Burow's solution  
Antibiotics - topical first line  
Antibiotics - oral for complicated cases or topical failures  
Topical acetic acid  
Pain control - analgesics  
Avoid oral steroids  
Intravenous antibiotics - necrotizing otitis externa  

Prevention Options

Prevention options are summarized in the Table II.

Table II.

Prevention Options for Swimmer's Ear
Preventing water from entering the ear canal Removing water from the ear canal
There is no great way to do this. Ear plugs may help, but have not been proven. Remove ear wax from ear canal prior to swimming. Many over the counter products are available or to be certain - check with a physician
Avoid plugging the ear canal with petroleum jelly - this does not work, and may make things worse Shaking one's head or jumping up and down to dislodge trapped water after the aquatic activity
Maximize therapy for underlying primary dermatological condtions (example: psoriasis) Hair dryer on low heat
Avoid aquatic activities Fanning the ear canal after exposure
The use of prophylactic acidifiying drops per and post water exposure - such as acetic acid otic drops Avoiding cotton tip applicators (Q-tips®) - they can push cerumen deep into the canal causing blockage. They can also traumitize the lining of the ear canal casuing microerosions and increasing risk for cellulitis

Optimal Therapeutic Approach for this Disease

Have the patient stay out of the water until the patient is clear.

Topical antibiotics are the first-line treatment. Flouroquinolones are the author’s first-line choice. Aminoglycosides can be used. One word of caution. If the tympanic membrane is ruptured the use of topical aminoglycosides may increase the patient’s risk for developing an ototoxic drug reaction.

Any of the following can be used alone for uncomplicated swimmer’s ear (5 drops = 0.25ml):

Topical ciprofloxacin 0.2% otic solution (Cetraxal®). 3-4 drops applied twice daily for 7 days. The efficacy and safety in children more than 1 year of age was studied in the reference below by Roland et al. This therapy is well tolerated in individuals more than 1 year of age. There are no studies in children under 1 year of age.

Topical oflaxacin 0.3% otic solution (Floxin®). Patients 13 years and older, 10 drops once daily for 7 days. For patients 6 months to 13 years old - 5 drops once daily for 7 days. The author’s preferred option.

Topical otic solutions with ciprofloxicin 0.3%/dexamethasone 0.1% sterile solution (Ciprodex®). Insert 4 drops 4 times daily for 7 days.

Topical hydrocortisone/neomycin/polymyxin B suspension (Cortisoprin Otic®). 3-4 drops every 6-8 hours for 10 days.

Topical acetic acid/aluminum acetate (Domeboro Otic®). 2-3 drops every 4 hours while awake for 7 days.

Topical acetic acid/propylene glycol (VoSol®). 5 drops every 6- 8 hours for 7 days.

Pain control with ibuprofren or acetaminophen.

If there is no relief or symptoms worsen with the above agents the patient needs to contact you. They should see improvement by 4 days.

If the swelling is severe an ear wick should be inserted in the canal by a pediatrician, ENT or appropriately trained individuals.

Complicated otitis externa (failed topical therapy, immunosuppressed, diabetic) should be treated with an oral fluoroquinolone. Oral floroquinolones are not FDA approved for this indication in the pediatric population. (Oral and intravenous ciprofloxacin are approved for pediatric cystic fibrosis patients with pseudomonal lung infections, inhalation anthrax and complicated Escherichia coli pyleonephritis.)

Children have been successfully treated with oral floroquinolones, for serious infections. Consult a pediatric infectious disease specialist. If the benefits outweigh the risks they should be used.

Ciprofloxacin 500mg orally twice daily for 7 days is the author’s treatment of choice in conjunction with one of the above topical therapies.

Referral to ENT is required if you at all consider necrotizing otitis externa.

Patient Management

Almost all patients will clear with water avoidance and a topical agent. If patients do not improve in 4 days they should contact you for reevaluation. If the patient is worsening on topical therapy, fever, or any evidence of facial cellulitis they should be referred to ENT for evaluation for malignant otitis externa.

Follow up with the culture results to make sure you are covering the appropriate agent.

Refer to ENT if necrotizing otitis media is suspected.

If you are seeing multiple patients that you think may have a common source (local pool), contact your local or state heath department so they can investigate.

Unusual Clinical Scenarios to Consider in Patient Management

MRSA appears to be an emerging cause of swimmer’s ear, hence a culture should always be performed at the initial visit.

Streptococcal and anaerobic bacteria have also been implicated.

There is a risk of development of necrotizing (malignant) otitis externa. (See section on systemic implications and complications).

Rare fungal causes have included Candida and Aspergillus species.

What is the Evidence?

Strauss, MB, Dierker, RL. "Clin Dermatol". vol. 5. 1987. pp. 103-111.

(Excellent review of the pathophysiology, treatment and prevention of otitis externa. Uses actual case studies to make various points on diagnosis and therapy. Includes a fabulous table of all otic preparations used at the time of publication.)

Handzel, O, Halperin, D. "Necrotizing (malignant) external otitis". Am Fam Physician. vol. 68. 2003. pp. 309-312.

(Wonderful review of necrotizing external otitis. Discusses pathophysiology and has many recommendations for imaging testing, follow up and therapeutic options.)

Kaushik, V, Malik, T, Saeed, SR. "Interventions for acute otitis externa (review)".

(As with all Cocharne database reviews a nice compilation of most studies ever performed on the therapy of otitis externa. Over 100 pages long, it is a task to read and somewhat difficult to find the information you are looking for. The end recommendations are not strong, but they do give some guiding principles.)

Nussinovitch, M, Rimon, A, Volovitz, B, Raveh, E, Prais, D, Amir, J. "Cotton-tip applicators as a leading cause of otitis externa". Int J Ped Otolaryngol. vol. 68. 2004. pp. 433-435.

(Recommends against using cotton-tipped applicators to clean the ears in children. They conclude this is likely the leading cause for predisposing an individual to developing otitis externa.)

Silvestre, JF, Betlloch, MI. "Cutaneous manifestations due to pseudomonas infection". Int J Dermatol. vol. 38. 1999. pp. 419-431.

(A thorough review of all cutaneous manifestations of pseudomonas infections. Small section on swimmer's ear and necrotizing external otitis.)

Marom, T, Yelin, R, Goldfarb, A, Rakover, Y, Shlizerman, L, Eilat, E. "Comparison of safety and efficacy of foam-based versus solution-based ciprofloxacin for acute otitis externa". Otolaryngol Head Neck Surg. vol. 143. 2010. pp. 492-499.

(Comparison of safety and efficay of foam-based versus solution-based ciprofloxacin for acute otitis externa. Phase 2 study looking at the safety of using foam based ciprofloxacin vs traditional solution based agents. Both treatments were equally effective. This foam based medication is not yet available.)

Roland, PS, Pien, FD, Schultz, CC, Henry, DC, Conroy, PJ, Wall, GM. "Efficacy and safety of topical ciprofloxacin/dexamethasone versus neomycin/polymxin B/hydrocortisone for otitis externa". Curr Med Res Opin. vol. 20. 2004. pp. 1175-1183.

(Study comparing the two otic antibiotic solutions in patients 1 year of age and older. Both therapies were well tolerated, clinical cure rates and bacterial eradication were higher with the ciprofloxacin/dexamethasone regimen.)

Ruben, RJ. "Efficacy of oflaxacin and other otic preparations for otitis externa". Pediatric Infect Dis J. vol. 20. 2001. pp. 108-110.

(Reviews the efficacy and safety of various preparations for treating otitis externa topically in children more than 12 years of age.)

Schwartz, RH. "Once-daily ofloxacin otic solution versus neomycin sulfate/polymyxin B sulfate/hydrocortisone otic suspension four times a day: a multicenter, randomized, evaluator-blinded trial to compare the efficacy, safety, and pain relief in pediatric patients with otitis externa". Curr Med Res Opin. vol. 22. 2006. pp. 1725-1736.

(Studied children 6 months of age to 12 years of age. Well tolerated therapy with oflaxacin otic 5 drops once daily for 7 -10 days. The author concludes that oflaxacin otic is a better choice over neomycin/polymyxin B/hydrocortisone because of a much decreased risk of ototoxicity.)
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