AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

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• 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
• References

Background

Otitis externa (OE) is a common disease affecting all age groups.¹ OE usually represents an acute bacterial infection of the skin of the ear canal but can be caused by a fungal infection. Although OE rarely causes prolonged problems or serious complications, the infection is responsible for significant pain and acute morbidity.

Pathophysiology

OE is a superficial infection of the skin in the ear canal. Two common initiating events may lead to OE. If trapped in the ear canal, moisture may cause maceration of the skin and provide a good breeding ground for bacteria. This may occur after swimming (especially in contaminated water) or bathing, hence the common lay-term swimmer's ear. It may also occur in hot humid weather (when OE is more prevalent).

The second significant factor is trauma to the ear canal that allows invasion of bacteria into the damaged skin. This often occurs after attempts at cleaning the ear with a cotton swab, paper clip, or any other utensil that can fit into the ear.

Once infection is established, an inflammatory response occurs with skin edema. Exudate and pus often appear in the ear canal as well. If severe, the infection may spread and cause a cellulitis of the face or neck. The most common pathogen is Pseudomonas aeruginosa, followed by Staphylococcus aureus, then other gram-negative organisms. Occasionally, fungi, such as Candida or Aspergillus species, cause OE.

Necrotizing (or malignant) OE is a complication that occurs in patients who are immunocompromised or in those who have received radiotherapy to the skull base. In this condition, bacteria invade the deep soft tissues and cause osteomyelitis of the temporal bone. This is a life-threatening disorder with an overall mortality rate that approached 50% historically.

Frequency

United States

OE is a very common disease that occurs in all regions of the United States. The infection is believed to be more prevalent in hot and humid conditions.

International

Although OE is a very common disease that occurs worldwide, the infection is believed to be more prevalent in hot and humid conditions.

Mortality/Morbidity

• OE can cause severe otalgia requiring narcotic pain relievers in some patients.
• Temporary hearing loss is common secondary to canal occlusion.
• Severe infections may cause lymphadenitis or cellulitis of the face or neck.
• Necrotizing OE is a serious condition that requires prolonged treatment and often results in severe morbidity or mortality.

Race

No racial disposition is known.

Sex

OE affects both sexes equally.

Age

Although the infection can affect all age groups, OE appears to be most prevalent in the older pediatric and young adult population.

CLINICAL

Section 3 of 11  

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

History

Patients with otitis externa (OE) may complain of the following:

• Otalgia ranging from mild to severe
• Hearing loss
• Ear fullness or pressure
• Tinnitus
• Fever (occasionally)
• Ear discharge
• Itch (especially in fungal infections or chronic OE)
• Severe deep pain (If experienced by a patient who is immunocompromised or diabetic, be alerted to the possibility of necrotizing OE.)

Physical

Characteristics of OE present upon physical examination may include the following:

• Pain upon palpation of the tragus (anterior to ear canal) or when applying traction to the pinna (hallmark of OE)
• Edema and redness of the ear canal (see Media file 1)
• Purulent or serous discharge in the ear canal
• Conductive hearing loss
• Cellulitis of the face or neck or lymphadenopathy of the unilateral neck (in some patients)
• Fungal OE characteristics include the following:
• • Fungal infections result in severe itch but less pain than bacterial OE.
  • A thick discharge that may be white or gray is often present.
  • Upon close examination, the discharge may have visible fungal elements or a fuzzy appearance.
• Necrotizing (malignant) OE characteristics include the following:
• • The sine qua non of necrotizing OE is pain out of proportion to clinical findings.
  • Upon close examination, granulation tissue may be present in the ear canal.

Causes

Risk factors for OE include swimming (hence, the commonly used term swimmer's ear), any source of water trapped in the ear canal, trauma to the ear canal, and a hot humid environment.

• Causative organisms for OE: These are usually Pseudomonas species, S aureus, or other gram-negative organisms.
• Fungal OE
• • Fungal OE may result from overtreatment of the ear canal with topical antibiotics, or it occasionally may present de novo from moisture trapped in the ear canal.
  • The most common organisms involved with fungal OE are Candida and Aspergillus species; however, many others have been isolated.
• Chronic OE
• • Chronic OE is a fairly common condition that may be the result of incomplete treatment of acute OE.²
  • However, chronic OE more often is caused by overmanipulation of the ear canal due to cleaning and scratching.
  • This results in a low-grade inflammatory response that further causes itching of the skin.
  • Eventually the skin thickens, and canal stenosis may occur.
• Necrotizing OE: Necrotizing OE occurs in patients who are immunocompromised and represents a true osteomyelitis of the temporal bone.

DIFFERENTIALS

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Other Problems to be Considered

Ear canal trauma
Temporomandibular Joint Syndrome
Ear canal foreign body
Ear canal carcinoma
Otitis media with a perforation or ventilation tube present

WORKUP

Section 5 of 11  

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• Medication
• Follow-up
• Miscellaneous
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Lab Studies

• Most persons with otitis externa (OE) are treated empirically.
• A culture taken from the ear canal discharge may be helpful in individuals with OE that is not responding to the usual measures.

Imaging Studies

• Imaging studies are only performed in persons with suspected necrotizing OE (ie, malignant).
• Classically, radionucleotide bone scan and gallium scan have been used to make the diagnosis.
• Currently, high-resolution CT scanning of the temporal bone plays a more important role.
• Although MRI has not been used to the same extent as these other tests, MRI may also be useful.

Procedures

• Use of an ear wick helps topical medication penetrate a severely swollen ear canal.
• The wick may be commercially prepared from a hard sponge material that expands when wet (eg, Merocel ear wick, Pope Oto-Wick), cut from a bigger sponge by the physician, or made from a narrow packing gauze.
• The wick is placed in the ear canal (unfortunately, this causes brief but significant discomfort) and is moistened with topical antibiotic eardrops.
• The ear wick usually is removed after 2-3 days.

TREATMENT

Section 6 of 11  

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• Follow-up
• Miscellaneous
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Medical Care

• Topical treatment
• • Most cases of acute otitis externa (OE) respond well to topical treatment.
  • Antibiotic eardrops, with or without a steroid, are the mainstay of treatment.
  • Topical acidifying and drying agents may be used in mild or resolving cases and are useful in fungal infections.
  • Some patients require strong analgesics for the first few days of treatment.
• Oral antibiotics
• • Most persons with OE do not require oral medications.
  • Administer oral antibiotics in individuals with cellulitis of the face or neck skin or in persons in whom severe edema of the ear canal limits penetration of topical agents.
  • Consider oral antibiotics in patients who are immunocompromised.
• Intravenous antibiotics
• • Intravenous (IV) antibiotics are used in individuals with necrotizing OE.
  • They may also be appropriate in patients with severe cellulitis or in persons whose symptoms do not respond to topical and oral antibiotics.
  • A prolonged course of IV antibiotics lasting as many as 6 weeks may be needed for individuals with necrotizing OE.
  • If the patient is stable, IV antibiotics may be administered at home.
  • Begin treatment with antibiotics to cover pseudomonads and alter medication depending on culture results.

Surgical Care

• Debridement
• • Surgical debridement is occasionally required in individuals with necrotizing (ie, malignant) OE.
  • Debridement of the ear canal is often necessary in more severe cases of OE or when a significant amount of discharge is present in the ear.
  • An otolaryngologist usually performs debridement using magnification and suction equipment.
  • Debridement is the mainstay of treatment for fungal infections.
• Incision and drainage
• • Occasionally, an abscess forms in the ear canal. This usually occurs in OE caused by S aureus.
  • The abscess often requires a simple incision and drainage procedure that is usually performed by an otolaryngologist using a needle or small blade.

Consultations

• Consider consultation with an otolaryngologist for persons with severe OE or when the patient does not respond to treatment as expected. Debridement of the ear canal is often necessary for resolution of the infection (see Surgical Care).
• Necrotizing OE necessitates consultation with otolaryngology, infectious disease, and, in some instances, neurosurgery.

Activity

• During treatment of OE and for 1-2 weeks following its resolution, advise the patient to keep the ear canal dry.
• During bathing or showering, advise the patient to place an earplug or cotton ball lightly coated with petroleum jelly in the ear canal to prevent water penetration.

MEDICATION

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Drug Category: Otic antibiotic agents

Most individuals with otitis externa (OE) may be treated with topical antibiotic preparations. Some preparations also contain a corticosteroid ingredient to decrease inflammation.

Drug Category: Otic acidifying agents

These agents are useful in fungal OE or in mild infections believed to be bacterial. They can also be useful for prevention.

Drug Category: Oral antibiotics

These agents are used to treat severe infection or cellulitis. Fluoroquinolones are drugs of choice because of Pseudomonas species coverage.

FOLLOW-UP

Section 8 of 11  

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• Follow-up
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Further Outpatient Care

• Monitor patients to ensure complete resolution. Usually a follow-up visit one week after starting treatment is adequate.

Deterrence/Prevention

Some patients acquire otitis externa (OE) multiple times and should use a preventive strategy.

• Earplugs worn for swimming and bathing are effective. Wipe earplugs with rubbing alcohol after use.
• Acidifying drops placed in the ear after swimming or bathing also have a prophylactic benefit.

Complications

• Complications of OE are rare. As mentioned, cellulitis or lymphadenitis may occur and should be treated with an oral antibiotic therapy.

Prognosis

• Most incidents of OE resolve without difficulty.
• Pain usually improves 2-5 days after initiating therapy.
• Most incidents of OE resolve in 7-10 days.
• In some patients with OE, the ear must be debrided prior to full resolution.

Patient Education

• For excellent patient education resources, visit eMedicine's Ear, Nose, and Throat Center Center. Also, see eMedicine's patient education article Swimmer's Ear.

MISCELLANEOUS

Section 9 of 11  

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• Miscellaneous
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Medical/Legal Pitfalls

• Failure to recognize necrotizing (ie, malignant) otitis externa (OE) is a significant pitfall. A patient who is diabetic or immunocompromised with severe pain in the ear should have necrotizing OE excluded by an otolaryngologist.
• Although rare, malignant tumors of the ear canal sometimes are misdiagnosed as OE. If the condition does not respond to treatment as expected, an otolaryngologist should evaluate the patient.
• Use of aminoglycoside antibiotic eardrops in the presence of a perforation or ventilation tube may cause problems. Although this is controversial, many otolaryngologists believe that aminoglycoside eardrops may be ototoxic if they enter the middle ear. In this situation, using an alternative such as quinolone drops may be safer.

MULTIMEDIA

Section 10 of 11  

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• Follow-up
• Miscellaneous
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Media file 1:  Acute otitis externa. The ear canal is red and edematous, and discharge is present.
	View Full Size Image
Media type:  Photo

REFERENCES

Section 11 of 11

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• References

1. Rowlands S, Devalia H, Smith C, et al. Otitis externa in UK general practice: a survey using the UK General Practice Research Database. Br J Gen Pract. Jul 2001;51(468):533-8. [Medline].
2. Roland PS. Chronic external otitis. Ear Nose Throat J. Jun 2001;80(6 Suppl):12-6. [Medline].
3. Benjamin B, Bingham B, Hawke M. A Colour Atlas of Otorhinolaryngology. London, UK: Martin Dunitz Ltd; 1995.
4. Bluestone CD, Klein JO. Otitis Media in Infants and Children. Philadelphia, PA: WB Saunders; 1988.
5. Hawke M, Jahn AF. Diseases of the Ear: Clinical and Pathologic Aspects. Philadelphia, PA: JB Lippincott Co; 1988.
6. Hawke M, Keene M, Alberti PW. Clinical Otoscopy: An Introduction to Ear Diseases. Edinburgh, UK: Churchill Livingstone; 1990.
7. Holten KB, Gick J. Management of the patient with otitis externa. J Fam Pract. Apr 2001;50(4):353-60. [Medline].
8. Hughes E, Lee JH. Otitis externa. Pediatr Rev. Jun 2001;22(6):191-7. [Medline].
9. Tierney PA, Price T, Gillet D. Improving standards in the treatment of acute otitis externa by the use of a treatment protocol and open access to aural toilet. J Laryngol Otol. Feb 2001;115(2):87-90. [Medline].
10. Waitzman AA, Hawke, M. Otoscopic examination: what to look for in the external ear. Consultant. 1996;36(5).
11. Walshe P, Rowley H, Timon C. A worrying development in the microbiology of otitis externa. Clin Otolaryngol. Jun 2001;26(3):218-20. [Medline].

Article Last Updated: Mar 14, 2008