AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
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Background

Otitis externa is an infection of the external ear canal and is a common problem in most EDs. Usually simple to care for, external otitis may lead to serious problems in people who are diabetic or immunocompromised. Basic treatment measures cure 90% of cases without complication.

Otitis externa is defined as chronic when the duration of the infection exceeds 4 weeks or when more than 4 episodes occur in 1 year.

Pathophysiology

Glands within the ear canal produce a layer of protective cerumen. Too little cerumen may predispose to infection, while too much cerumen may cause retention of water and debris. Most ear canal infections are caused by excessive moisture carrying bacteria into the cerumen of the ear canal, leading to maceration and inflammation. Another common cause is local trauma allowing bacteria to enter compromised skin. The most common causative organism is Pseudomonas species. Staphylococci, streptococci, and (in rare cases) fungi are other causative agents.

Otitis externa can also result from nonbacterial origins such as atopic dermatitis or allergic contact dermatitis.

Frequency

United States

Acute otitis externa occurs in 4 of every 1000 people each year, and the chronic form affects 3-5% of the population. The condition is most common in persons who are swimmers and/or divers or who have other exposures that allow contaminated water to be trapped in the external canal.

Mortality/Morbidity

Infection of the deep structures (ie, malignant external otitis) occurs almost exclusively in patients who are immunocompromised. People who are diabetic are particularly vulnerable.

• This complication should be suspected if tenderness, erythema, and edema of the external ear or adjacent tissues are present.
• This condition can lead to cellulitis and osteomyelitis, with the untreated mortality rate approaching 50%.
• When a fever, other signs of systemic toxicity, or underlying immunocompromise is present, the patient may need admission and treatment with high-dose antibiotics covering Pseudomonas species.
• Life-threatening temporal bone infection occurs in less than 0.5% of cases.

Race

People in some racial groups have small ear canals, which may predispose them to obstruction and infection.

Sex

Rates of occurrence are equal in males and females.

Age

All ages are affected, with a peak incidence in children aged 7-12 years.

CLINICAL

Section 3 of 11  

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• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

History

• In general, a history of 1-2 days of progressive ear pain
• Frequently, a history of exposure to water
• Itching
• Purulent discharge
• Conductive hearing loss
• Feeling of fullness or pressure

Physical

• The sine qua non of otitis externa is pain on gentle traction of the external ear.
• Periauricular adenitis may occur, but it is not necessary for the diagnosis.
• Speculum examination of the canal reveals erythema, edema of the epithelium, and accumulation of moist debris in the canal.
• The tympanic membrane may be difficult to visualize and may be mildly inflamed, but it should be normally mobile on insufflation.
• Spores and hyphae may be seen in the external canal, if the etiology is fungal.
• Eczema of the pinna may be present.
• By definition, cranial nerve (CN) involvement (ie, of CNs VII and IX-XII) is not associated with simple otitis externa.

Causes

• Traumatized external canal (particularly due to cotton-tipped swabs)
• Bacterial infection
• • Pseudomonas species (38-50% of all cases)
  • Staphylococcus species
  • Gram-negative rods
• Fungal infection (rare, 10%) - Aspergillus species
• Yeast (rare) - Candida species
• Eczematous otitis externa
• • Eczema
  • Seborrhea
  • Neurodermatitis
  • Contact dermatitis from earrings or hearing aid use
  • Purulent otitis media with perforation of the tympanic membrane and drainage (This may mimic findings in otitis externa, but it is usually painless and has no swelling of the canal.)
  
  
  • Sensitivity to topical medications
• Chronic otitis externa is usually a result of nonbacterial sources as described above, but it can also result from inadequately treated acute otitis externa.

DIFFERENTIALS

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Other Problems to be Considered

Chondritis
Cranial nerve palsy
Hearing loss
Wisdom tooth eruption
Intracranial abscess
Cavernous sinus thrombosis

WORKUP

Section 5 of 11  

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Lab Studies

• Gram staining and culture of the canal discharge is occasionally helpful, particularly when a fungal cause is suspected.
• Patients with a fever or signs of toxicity should receive a standard laboratory assessment. No tests are necessary to diagnose external otitis beyond history taking and physical examination.

Imaging Studies

• If the patient has toxicity or signs of bony involvement, CT scanning of the mastoid may be appropriate.

Other Tests

• Adults with otitis externa may benefit from a screening blood glucose (chemstick) and/or a urine dipstick test to rule out occult diabetes.

Procedures

• Gentle cleaning with a soft plastic curette or a small Frazier suction tip may be performed. Irrigation with a mix of peroxide and water may be helpful in removing debris from the canal but only if able to determine that the tympanic membrane is intact. Any water instilled must be successfully removed to avoid worsening of the condition.
• Wick placement (see Treatment section) may be needed to facilitate delivery of the prescribed medications.
• Pneumatic otoscopy may be used to evaluate for otitis media.

TREATMENT

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Emergency Department Care

• Care generally involves diagnosing otitis externa, cleaning debris from the canal (if possible), and providing patient education and prescriptions.
• Use of an ear wick with a simple acidifying solution cures most cases of otitis externa in a few days.
• • If the canal is significantly edematous, a foam (Pope) or gauze wick (quarter-inch packing works well) may be inserted to facilitate the delivery of medications. The foam wicks are highly compressed and expand with absorption of liquids.
  • The gauze wick may be wound over the tip of a small metal or wood probe and inserted into the canal.
  • For the first several days, the medication drops are placed on the external end of the wick and carried into the recesses of the ear canal. As the edema decreases, the wick falls out or is removed.
• Most physicians prescribe topical antibiotics.
• • Prior to antibiotic therapy, astringents and acetic acid solutions (VoSol) were used to treat otitis externa. These solutions can be painful to inflamed ear canals.  Currently, these solutions are primarily used for preventative measures.
  • An aminoglycoside combined with a second antibiotic and a topical steroid such as neomycin, polymyxin B, and hydrocortisone used to be the most commonly prescribed topical antibiotic. However, caution must be used to watch for a hypersensitivity reaction to the neomycin and ototoxicity from the aminoglycoside. This preparation should not be used in cases of a perforated tympanic membrane, which is not always easy to determine in cases of otitis externa.
  • In 1990, fluoroquinolones became available as topical antibiotics. More recently, ofloxacin (1997) and ciprofloxacin (1998) became approved by the US Food and Drug Administration (FDA) as topical therapy for otitis externa. Fluoroquinolones are not associated with ototoxicity, and ofloxacin is safe in cases of a perforated tympanic membrane. Ofloxacin otic is the drug of choice when a perforated tympanic membrane cannot be ruled out.
  • Mild fungal infections can usually be treated with an acetic acid solution, while more severe cases may require a topical antifungal such as 1% clotrimazole. 
• Mildly affected afebrile patients with ear involvement may be monitored closely on an outpatient basis with antibiotics.
• Analgesics, antipruritics, and/or antihistamines may be indicated.

Consultations

In general, the otorhinolaryngologist (ENT) is not involved unless the patient has a suppurative complication or has a perforated tympanic membrane.

MEDICATION

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The agents used include analgesics for pain relief and acidifying solution to treat the infection. Oral antibiotics rarely are used or are necessary to treat simple otitis externa.

Drug Category: Analgesics

Otitis externa is quite painful for some, and patients frequently request analgesics. Inexpensive simple nonsteroidal anti-inflammatory drugs (NSAIDs) and/or narcotics are appropriate. In some cases, systemic analgesics are helpful before ear cleaning or wick placement.

Drug Category: Acidifying agents

The inflammation and accumulated debris allow the growth of Pseudomonas species. This growth is counteracted by the use of mild acidifying medications, such as acetic acid solutions (eg, VoSol).

Drug Category: Otic antibiotics

These agents are commonly prescribed for treating otitis externa with cure rates between 87% and 97%.

FOLLOW-UP

Section 8 of 11  

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• Follow-up
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Deterrence/Prevention

• Patients who have recurrent episodes of otitis externa should be taught to use acidifying drops in the ears after every exposure to water to prevent recurrences.

• Attention to elimination of water after swimming or bathing may help prevent recurrence. The use of a blow dryer on a low setting after swimming to dry the ear canal has been suggested as a preventive measure. No studies have demonstrated the effectiveness of this suggestion.

• Nonprescription drops are available, and some even use a couple of drops of vinegar.

• Patients should avoid frequently washing the ear canal with soap because this makes the ear canal more alkali and thus more prone to infection.

Complications

• Malignant otitis externa is the only significant complication.

• Most frequently, the disease occurs in diabetic patients and involves bacterial spread to the cartilage of the external ear with pain and edema.

• It may be accompanied by a fever and systemic manifestations of infection.

• Treatment requires parenteral antibiotics with coverage for Pseudomonas species, in addition to local care.

• These patients may require specialty consultation and hospitalization.

• Acute otitis externa may spread to the pinna, resulting in a chondritis, particularly in patients with newly pierced ears.

• Diabetic ketoacidosis is often present in diabetics with this condition.

Prognosis

• Most patients with external otitis improve greatly within 48-72 hours and are well in 1 week to 10 days.

• Failure to improve within several days should call the diagnosis into question and prompt the physician to reevaluate the patient.

• Surgical intervention is required occasionally for chronic otitis externa.

• Resolution of eczematous otitis externa occurs with control of the primary skin condition.

Patient Education

• Prevention by using acidifying drops is encouraged in patients with recurrent episodes of external otitis.

• Avoidance of cotton-tipped swabs to avoid ear canal trauma should be discussed with patients. Improper use of cotton-tipped applicator sticks simply packs cerumen into the canal and can cause trauma to the tympanic membrane.

MISCELLANEOUS

Section 9 of 11  

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• Clinical
• Differentials
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• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

• Failure to recognize the occasional patient with malignant external otitis and then to provide that patient with systemic therapy is the worst error related to this condition.
• Adults infrequently have external otitis; adult patients with this condition should be screened for diabetes, which places them at risk for complications.

Special Concerns

• Children may insert a foreign body (FB) in their ear canal and not mention it to parents.
• If any pain accompanies purulent drainage, consider the presence of a FB.
• The patient with a FB will not improve until it is removed.

MULTIMEDIA

Section 10 of 11  

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• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  Otitis externa with ear wick in place. Note discharge from canal and swelling of canal.
	View Full Size Image
Media type:  Photo

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

• Ann Otol Rhinol Laryngol Suppl. Diagnosis and treatment of acute otitis externa: an interdisciplinary update. Feb 1999;176:1-23. [Medline].
• Beers SL, Abramo TJ. Otitis externa review. Pediatr Emerg Care. Apr 2004;20(4):250-6. [Medline].
• Block SL. Otitis externa: providing relief while avoiding complications. J Fam Pract. Aug 2005;54(8):669-76. [Medline].
• Bluestone CD. The ear. In: Nelson's Textbook of Pediatrics. Philadelphia, PA: WB Saunders Co; 1979:1182-4.
• Brook I. Treatment of otitis externa in children. Paediatr Drugs. Oct-Dec 1999;1(4):283-9. [Medline].
• Cantor RM. Otitis externa and otitis media. A new look at old problems. Emerg Med Clin North Am. May 1995;13(2):445-55. [Medline].
• Halpern MT, Palmer CS, Seidlin M. Treatment patterns for otitis externa. J Am Board Fam Pract. Jan-Feb 1999;12(1):1-7. [Medline].
• Hickham M, Amedee RG. Malignant otitis externa. J La State Med Soc. Dec 1996;148(12):511-3. [Medline].
• Mirza N. Otitis externa. Management in the primary care office. Postgrad Med. May 1996;99(5):153-4, 157-8. [Medline].
• Niparko JK. Hearing loss and associated problems. In: Principles of Ambulatory Medicine. 4^th ed. Lippincott Williams & Wilkins; 1995:1408-9.
• Osguthorpe JD, Nielsen DR. Otitis externa: Review and clinical update. Am Fam Physician. Nov 2006;74(9):1510-6. [Medline].
• Rosenfeld RM, Singer M, Wasserman JM, Stinnett SS. Systemic review of topical antimicrobial therapy for acute otitis externa. Otolaryngol Head Neck Surg. Apr 2006;134(4 Suppl):S24-48. [Medline].
• van Asperen IA, de Rover CM, Schijven JF, et al. Risk of otitis externa after swimming in recreational fresh water lakes containing Pseudomonas aeruginosa. BMJ. Nov 25 1995;311(7017):1407-10. [Medline].

Article Last Updated: Jul 26, 2007