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Am Fam Physician. 2023;107(2):145-151

Patient information: See related handout on acute otitis externa (swimmer's ear), written by the authors of this article.

This clinical content conforms to AAFP criteria for CME.

Author disclosure: No relevant financial relationships.

Acute otitis externa is an inflammatory condition that affects the external ear canal. It is usually of rapid onset and is generally caused by bacterial infection. The primary bacterial infections are Pseudomonas aeruginosa and Staphylococcus aureus. Acute otitis externa presents with pain (otalgia), redness, and swelling of the canal. It is more common in children and young adults. Tenderness on movement of the pinna or tragus is the classic finding. Analgesics and topical antibiotics are the mainstays of therapy. Topical medications include acetic acid 2%, aminoglycosides, polymyxin B, and quinolones with and without corticosteroids. There is no evidence that any one preparation is clinically superior to another, and the choice of treatment is based on factors such as cost, whether the tympanic membrane is intact, and patient adherence. Oral antibiotics are indicated only if evidence of cellulitis occurs outside of the ear canal or if associated conditions such as immunocompromise, diabetes mellitus, or conditions that would not allow for the use of topical treatment are found. Duration of topical treatment is usually seven to 10 days. Keys to prevention include avoiding injury to the ear canal and keeping it free of water.

Acute otitis externa, also known as swimmer's ear, is an inflammatory condition affecting the external ear canal that is a common problem encountered in primary care offices. This article provides a brief update and summary of the best available patient-oriented evidence for treating acute otitis externa.

RecommendationSponsoring organization
Do not prescribe oral antibiotics for uncomplicated acute external otitis.American Academy of Otolaryngology–Head and Neck Surgery


  • Acute otitis externa occurs in all age groups. An estimated 10% of people will develop acute otitis externa during their lifetime.1 Younger age groups are most commonly affected, with decreased incidence as one ages (Table 12).

  • Acute otitis externa is responsible for more than 500,000 emergency department visits each year.3

  • Risk factors for acute otitis externa are summarized in Table 2,4 with the most common factor being swimming.4,5

Age (years)Incidence (%)
Birth to 47
5 to 919
10 to 1416
15 to 199
20 and older5
Anatomic abnormalities
Canal stenosis
Hairy ear canals
Canal obstruction
Foreign body
Impacted cerumen
Inclusion cyst
Cerumen/epithelial integrity
After cerumen removal
Earplug usage
Hearing aid or ear bud usage
Instrumentation or itching of canal
Dermatologic conditions
Water in canal
Swimming* or prolonged water exposure
Purulent otorrhea from otitis media
Soap irritation
Type A blood


  • The clinical diagnosis of acute otitis externa is based on symptoms of inflammation in the ear canal. Criteria proposed by the American Academy of Otolaryngology–Head and Neck Surgery to aid in diagnosis are listed in Table 3.5 Figure 1 and Figure 2 demonstrate the redness and edema of the canal seen with acute otitis externa.4

  • The most common symptom is pain in the tragus, pinna, or both,6 which is disproportionate to what is expected on visual inspection.5 Other causes that may be included in the differential diagnosis of ear canal inflammation are listed in Table 4.4

  • Physicians should review the presenting symptom onset and exposure to water (e.g., swimming) as well as any trauma to the canal and history of other skin conditions such as eczema, psoriasis, or seborrhea. Additional history should include prior surgeries, radiation therapy, or history of systemic illnesses such as diabetes mellitus, or conditions that may predispose to immune suppression.

  • The pinna, tragus, ear canal, and regional lymph nodes should be examined. Use of pneumatic otoscopy is recommended to help differentiate acute otitis externa from otitis media and to assist in determining that the tympanic membrane is intact without perforation because these determinations have implications for treatment options.4 If a perforation has occurred, the medications that can be used topically are limited.

  • An examination for signs of cellulitis or extension beyond the ear canal should be performed.

  • Cultures of otorrhea are usually not performed because most cases of acute otitis externa are caused by bacterial infection,7 predominantly with Pseudomonas aeruginosa or Staphylococcus aureus.

Rapid onset of symptoms (usually within 48 hours) in the past three weeks
Symptoms of ear canal inflammation
 Ear pain (otalgia)
 Sense of fullness
 With or without hearing loss or jaw pain
Signs of canal inflammation
 Pinna or tragus tenderness on movement
 Diffuse canal edema or redness
May also have otorrhea, tympanic membrane rupture, pinna cellulitis, or local lymphadenitis
ConditionDistinguishing characteristicsComments
Acute otitis mediaPresence of middle ear effusion, no tragal or pinnal tendernessUse pneumatic otoscopy or tympanometry; treat with systemic antibiotics
Chronic otitis externaItching is often the predominant symptom, found in the erythematous canal, lasts more than three monthsTreat underlying causes and conditions
Chronic suppurative otitis mediaChronic otorrhea, nonintact tympanic membraneControl otitis externa symptoms, then treat otitis media
Contact dermatitisAllergic reaction to materials (e.g., metals, plastics, soaps) in contact with the skin/epithelium; itching is the predominant symptomCheck for piercings or use of hearing aids, ear buds, or earplugs; discontinue exposure when possible
EczemaItching is the predominant symptom; often chronic; history of atopy, outbreaks in other locationsConsider treatment with topical corticosteroids
FurunculosisFocal infection, may be pustule or nodule, often in distal canalConsider treatment with heat, incision and drainage, or systemic antibiotics; can progress to diffuse otitis externa
Malignant otitis externaHigh fever, granulation tissue or necrotic tissue in ear canal, may have cranial nerve involvement; patient has diabetes mellitus or is immunocompromised, has elevated erythrocyte sedimentation rate, or has findings on computed tomographyMedical emergency with high morbidity rate and possible mortality; warrants emergent consultation with otolaryngologist, hospitalization, intravenous antibiotics, debridement
MyringitisTympanic membrane inflammation, may have vesicles; pain is often severe; no canal edemaUsually results from acute otitis media or viral infection
OtomycosisItching is predominant symptom, thick material in canal; less edema; may see fungal elements on otoscopyCan coexist with bacterial infections; treat with acetic acid, half acetic acid/half isopropyl alcohol, or topical antifungals; meticulous cleaning of ear canal
Ramsay Hunt syndromeHerpetic ulcers in canal; may have facial numbness or paralysis, severe pain, loss of tasteTreatment includes antivirals, systemic corticosteroids
Referred painNormal ear examinationLook for other causes based on patterns of referred pain
SeborrheaItching and rash on hairline, face, scalpTreatment includes lubricating or moisturizing the external auditory canal
Sensitization to oticsSevere itching, maculopapular or erythematous rash in conchal bowl and canal; may have streak on pinna where preparation contacted skin; vesicles may be presentType IV–delayed hypersensitivity reaction to neomycin or other components of otic solutions; discontinue offending agent; treat with topical corticosteroids



  • Per 2014 guidelines from the American Academy of Otolaryngology–Head and Neck Surgery,5 which were endorsed by the American Academy of Family Physicians and reaffirmed in 2019,8 treatment for acute otitis externa should include an assessment of pain. Using analgesics as a mainstay of therapy to help in the management of acute otitis externa allows for increased comfort and more rapid return to normal activities.9 Figure 3 presents an algorithm for treatment.5

  • Analgesics that can provide relief include acetaminophen, nonsteroidal anti-inflammatory drugs, or, in rare cases, the addition of a short-term opioid. Based on expert opinion, fixed dosing intervals are recommended rather than as-needed dosing.9

  • Available topical analgesics are limited to over-the-counter homeopathic medications for which there is no evidence of benefit. The use of otic benzocaine with or without antipyrine was withdrawn from the U.S. market in 2015.10 Concerns with the use of topical analgesics include the potential dilution of antibiotic drops and unknown ototoxicity if there is a perforated tympanic membrane.

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