Version July 2025
INTRODUCTION —
Otitis externa, also known as external otitis or swimmer's ear, refers to inflammation of the external auditory canal or auricle.
This topic will focus on the treatment of acute otitis externa (AOE). The pathogenesis, clinical manifestations, and diagnosis of AOE are discussed elsewhere. (See "Acute otitis externa in adults: Pathogenesis, clinical features, and diagnosis".)
Malignant otitis externa, which refers to extension of infection to the skull base, is discussed elsewhere, as are acute otitis media and chronic suppurative otitis media with tympanic membrane (TM) perforation, which may result in ear canal inflammation.
●(See "Necrotizing (malignant) external otitis".)
●(See "Acute otitis media in adults".)
●(See "Chronic otitis media and cholesteatoma in adults".)
●(See "Chronic suppurative otitis media (CSOM): Treatment, complications, and prevention".)
CLEANING THE EAR CANAL —
Cleaning out the external canal (aural toilet) is the first step in treatment. The removal of cerumen, desquamated skin, and purulent material from the ear canal greatly facilitates healing and enhances penetration of topical ear drops into the site of inflammation [1].
Ear canal cleaning should be performed using an otoscope that allows for direct visualization, employing a loop-tipped ear curette or cotton swab to remove cerumen and debris. If the tympanic membrane (TM) is intact, the ear canal can be irrigated (with a 1:1 dilution of 3% hydrogen peroxide with water at body temperature) to enhance debris removal.
In patients with a ruptured TM, or in those whose TM cannot be completely visualized, referral to otolaryngology (ENT)for cleaning and further management is appropriate. Otolaryngologists can clean infected ears using a microscope, which provides magnified binocular vision and allows the use of both hands for cleaning. This technique may facilitate cleaning when the ear is extremely tender.
TREATING THE INFECTION
Management approach — Our approach to treatment depends on the severity of the AOE, the presence of diabetes mellitus or immunocompromise, and the presence or absence of an intact tympanic membrane (TM).
Intact tympanic membrane — The treatment of mild to moderate AOE in immunocompetent patients with an intact TM is with topical medications (algorithm 1) [2]. For patients in whom the TM cannot be fully visualized, we avoid ototoxic agents and use the same treatment options as in patients with a nonintact TM (See 'Nonintact tympanic membrane or unknown tympanic membrane status' below.).
There are no randomized trials directly comparing topical with oral antibiotic therapies, and there are no trials comparing the addition of an appropriate oral antibiotic (eg, with coverage against typical otitis externa pathogens) with topical therapy alone.
●In a 1993 randomized trial in Australia including patients with mostly mild to moderate infection, there was no difference in the clinical response score comparing treatment with a topical ointment (containing an antifungal, a glucocorticoid, and two antibiotics) plus oral placebo with the same ointment plus oral trimethoprim-sulfamethoxazole [3]. It should be noted, however, that trimethoprim-sulfamethoxazole has no activity against Pseudomonas, a major pathogen in AOE. (See "Acute otitis externa in adults: Pathogenesis, clinical features, and diagnosis", section on 'Microbiology'.)
●In a multicenter randomized trial comparing topical ciprofloxacin/hydrocortisone alone with topical neomycin/polymyxin/hydrocortisone plus oral amoxicillin, there was no difference in treatment outcomes [4]. Oral amoxicillin, however, has no efficacy against Pseudomonas or most isolates of Staphylococcus aureus, the major causative pathogens of AOE.
Given the absence of any trial using oral antibiotics with activity against the usual pathogens, no conclusions can be drawn regarding relative efficacy of topical versus systemic treatment. However, topical antibiotics are preferred in patients with moderate disease and an intact TM in order to avoid the potential side effects of oral antibiotics.
Mild disease — Mild disease is characterized by minor discomfort and pruritus. There is minimal canal edema (picture 1).
For patients with mild AOE and an intact TM, we suggest treatment with a combination topical preparation such as acetic acid-hydrocortisone (an acidifying agent and a glucocorticoid) rather than other topical agents (table 1) (see 'Antiseptics and acidifying solutions' below and 'Glucocorticoids' below). We prefer not using a topical antibiotic in these patients because of the marginal additional benefit obtained.
The nonantibiotic topical preparations for the treatment of mild disease should be administered three to four times daily.
We prescribe an initial seven-day course of topical medication with instructions to continue it for one additional week if symptoms are improving but have not resolved. Patients who presented with mild disease but have symptoms persisting beyond two weeks or worsening during the course of treatment should be reevaluated for treatment failure, with repeat examination of the ear, cultures of any ear discharge, and prompt referral to ENT.
Moderate disease — Moderate disease is characterized by an intermediate degree of pain and pruritus. The canal may be partially occluded (picture 2).
For patients with moderate disease and an intact TM, we suggest treatment with a combination topical preparation that contains an antibiotic and a glucocorticoid rather than other topical preparations (table 1). The antibiotic should have coverage against S. aureus and Pseudomonas aeruginosa. Ciprofloxacin-hydrocortisone, ciprofloxacin-dexamethasone, or neomycin-polymyxin B-hydrocortisone are preferred first-line agents. We generally treat with ciprofloxacin-hydrocortisone or ciprofloxacin-dexamethasone; although they are more costly, they are associated with fewer side effects than neomycin-polymyxin B-hydrocortisone. (See 'Antibiotics' below.)
In ears where the integrity of the TM cannot be confirmed, neomycin-polymyxin B-hydrocortisone, other preparations containing aminoglycosides, and acidifying agents should be avoided due to potential ototoxicity.
Most topical preparations should be administered three to four times daily, although topical fluoroquinolones can be given twice daily.
We prescribe an initial seven-day course of topical medication with instructions to continue it for one additional week if symptoms are improving but have not resolved. Patients with moderate disease and symptoms persisting beyond two weeks, or worsening at any point, should be reevaluated for treatment failure with repeat examination of the ear, cultures of any ear discharge, and prompt referral to ENT.
Severe disease — Severe disease is characterized by intense pain, and on examination, the canal is completely occluded from edema (picture 3). Periauricular erythema, regional lymphadenopathy, and fever may be present.
For patients with severe disease and an intact TM, management includes topical therapy, and in some patients, wick placement and systemic antibiotics. In addition, cultures of the ear canal drainage should be obtained; the results may help guide therapy, particularly in patients who do not improve with empiric therapy.
●Topical therapy for all patients with severe disease – For severe AOE, we suggest treatment with a topical preparation that contains an antibiotic and a glucocorticoid rather than other topical preparations (table 1). The antibiotic should have coverage against S. aureus and P. aeruginosa. Ciprofloxacin-hydrocortisone, ciprofloxacin-dexamethasone, or neomycin-polymyxin B-hydrocortisone are good first-line agents. We generally prefer ciprofloxacin-hydrocortisone or ciprofloxacin-dexamethasone; although they are more costly, they are associated with fewer side effects than neomycin-polymyxin B-hydrocortisone. (See 'Antibiotics' below.)
However, in ears where the integrity of the TM cannot be confirmed, neomycin-polymyxin B-hydrocortisone, other topical preparations containing aminoglycosides, and acidifying agents should be avoided due to potential ototoxicity. (See 'Nonintact tympanic membrane or unknown tympanic membrane status' below.)
Most topical preparations should be administered three to four times daily, although topical fluoroquinolones can be given twice daily.
●Additional oral antibiotics for patients with fever – For patients with severe AOE who are febrile, we suggest dual therapy with both topical and systemic antibiotics. In general we use an oral fluoroquinolone (such as levofloxacin 500 mg orally once daily for seven days) for coverage against Pseudomonas. Providers should be aware of the potential adverse effects associated with fluoroquinolone use (see "Fluoroquinolones", section on 'Adverse effects'). For patients who are not candidates for systemic fluoroquinolones, treatment with an antistaphylococcal beta-lactam antibiotic, such as cefuroxime 500 mg orally twice daily or amoxicillin-clavulanate 875 mg orally twice daily for seven days, is an alternative, although these options do not have activity against Pseudomonas.
●Wick placement for patients with complete canal obstruction – Patients with canal obstruction due to swelling require wick placement to facilitate adequate delivery of topical medication. Wicks, made of polyvinyl alcohol sponge, expand as the ototopical medicine is applied. They allow topical medications to reach the medial aspect of the ear canal and can also facilitate longer retention of topical solution in the affected areas. If swelling persists, wicks should be replaced every one to three days but can be removed once ear canal swelling subsides. Wick placement usually requires referral to otolaryngology (ENT) but can also be performed by a primary care practitioner with experience in the procedure.
We prescribe an initial seven-day course of medication, with additional treatment possible depending on response to initial therapy. Patients with severe AOE are seen in follow-up within one week; patients requiring a wick and those with infection that has spread beyond the external ear canal are generally seen within three days to change the wick (if applicable) and to assess response to treatment.
Nonintact tympanic membrane or unknown tympanic membrane status — The treatment of patients with mild or moderate disease and a nonintact TM (eg, ruptured TM, tympanostomy tubes) or unknown TM status (eg, unable to clearly visualize on otoscopy) is similar to patients with an intact TM, with the exception of the preferred topical preparations and the recommendation for earlier referral to ENT if not responding to initial treatment. Our approach is consistent with the American Academy of Otolaryngology-Head and Neck Surgery (algorithm 1) [5].
●Initial topical treatment for all patients – For patients with a nonintact TM or unknown TM status (eg, unable to visualize), we suggest a seven-day course of treatment with a topical fluoroquinolone (eg, ciprofloxacin-dexamethasone, ciprofloxacin, ofloxacin) rather than other topical preparations (table 1).
In patients with AOE and a suspected or confirmed nonintact TM, ototoxic preparations containing aminoglycosides or alcohol, as well as acidic preparations, should not be given since they may reach the middle ear causing pain and ototoxicity [5]. Similarly, we avoid other topical otic antibiotics or antiseptics known to be ototoxic when they reach the middle ear or whose safety has not been established [6].
●Patients with fever or cellulitis – Patients with fever or complicating cellulitis should have systemic antibiotic coverage prescribed as part of initial therapy. As discussed above, empiric treatment options include levofloxacin 500 mg orally once daily, ciprofloxacin 500 mg orally twice daily, cefuroxime 500 mg orally twice daily, or amoxicillin-clavulanate 875 mg orally twice daily for one week. Of these options, only levofloxacin and ciprofloxacin have activity against Pseudomonas, and ciprofloxacin is the most active fluoroquinolone against Pseudomonas.
●Patients with an allergy to fluoroquinolones – For patients with a suspected or confirmed nonintact TM who cannot tolerate fluoroquinolones (eg, a history of associated anaphylaxis, hypersensitivity reactions with organ involvement or skin desquamation, neurologic side effects, or tendinitis), ear canal drainage should be cultured, and empiric treatment with an oral antibiotic (eg, cefuroxime 500 mg orally twice daily, or amoxicillin-clavulanate 875 mg orally twice daily for one week) should be started. The patient should also be referred to ENT. If ear drainage culture in such a patient grows Pseudomonas and the patient has failed to respond to the treatment given, a brief course of intravenous antibiotics with activity against the patient's Pseudomonas isolate may be required in order to treat the infection.
●Patients who do not improve – Patients who do not improve after one week of treatment should be referred to ENT. In addition, a culture of the external drainage should be obtained and empiric treatment with an oral antibiotic started (if not already done). Antibiotics may need to be changed once culture results are available.
In those rare patients with a nonintact TM, a ciprofloxacin-resistant Pseudomonas isolate in ear drainage cultures, and failure to respond to topical plus oral ciprofloxacin, a brief course of intravenous antibiotics may be necessary to clear the infection.
Patients with cellulitis — In some cases, severe AOE may be complicated by periauricular or facial cellulitis (picture 4).
For patients who have severe AOE complicated by preauricular or auricular cellulitis, we suggest dual therapy with both topical and systemic antibiotics. For such patients, in addition to obtaining cultures of the ear canal, topical and systemic treatment targeting S. aureus and Pseudomonas should be initiated. The type of systemic antibiotic will depend on the severity of the infection beyond the ear canal:
●Topical antibiotic therapy – For severe AOE complicated by cellulitis, we suggest treatment with a topical preparation that contains an antibiotic and a glucocorticoid rather than other topical preparations (table 1). The antibiotic should have coverage against S. aureus and P. aeruginosa. Ciprofloxacin-hydrocortisone, ciprofloxacin-dexamethasone, or neomycin-polymyxin B-hydrocortisone are good first-line agents. We generally prefer ciprofloxacin-hydrocortisone or ciprofloxacin-dexamethasone; although they are more costly, they are associated with fewer side effects than neomycin-polymyxin B-hydrocortisone. (See 'Antibiotics' below.)
However, in ears where the integrity of the TM cannot be confirmed, neomycin-polymyxin B-hydrocortisone, other topical preparations containing aminoglycosides, and acidifying agents should be avoided due to potential ototoxicity. (See 'Nonintact tympanic membrane or unknown tympanic membrane status' above.)
●Systemic antibiotic therapy – Patients with less severe cellulitis can be treated with oral antibiotics, whereas those with severe or rapidly progressing cellulitis may need intravenous (IV) antibiotics.
•For patients with less severe cellulitis, an oral fluoroquinolone (such as levofloxacin 500 mg orally once daily for seven days) may be given [7]. Providers should be aware of the potential adverse effects associated with fluoroquinolone use (see "Fluoroquinolones", section on 'Adverse effects'). For patients who are not candidates for systemic fluoroquinolones, treatment with an antistaphylococcal beta-lactam antibiotic, such as cefuroxime 500 mg orally twice daily or amoxicillin-clavulanate 875 mg orally twice daily for seven days, is an alternative, although these options do not have activity against Pseudomonas.
•For patients with more severe cellulitis, administration of IV antibiotics (eg, IV vancomycin plus IV cefepime) may be necessary until the infection is improving. The choice of oral antibiotic to complete the course of therapy can be guided by ear canal culture results. Additional details on treatment of cellulitis are reviewed elsewhere. (See "Acute cellulitis and erysipelas in adults: Treatment".)
Immunocompromised hosts — Regardless of the severity of infection, for all patients with immunosuppression (eg, chemotherapy, high-dose corticosteroids or other immunocompromising conditions, solid organ or stem cell transplant recipient, untreated or advanced HIV) and AOE, we suggest treatment with combined systemic and topical antibiotics rather than topical therapy alone. For such patients, the preferred topical and systemic antibiotics are the same as those used for severe disease. (See 'Severe disease' above.)
In addition, all patients with diabetes or immunosuppression who have AOE refractory to therapy (eg, persistent ear drainage or pain) should be referred to an otolaryngologist for further management of the AOE and evaluation for malignant otitis externa (see "Necrotizing (malignant) external otitis"). Referral to an infectious disease specialist may also be helpful.
Topical otic preparations: General principles — Topical therapy delivers a high concentration of medication to the infected and inflamed external tissue with few side effects [1,5,8]. Several classes of topical agents are available, including antibiotics, antiseptics, glucocorticoids, and acidifying solutions [1]. They come as single agents and in combination (table 1). Most preparations are in liquid form, although ointments and powders are also available. One meta-analysis of 19 randomized trials found no clinically meaningful differences between various topical interventions, except that acetic acid was less effective than antibiotic/glucocorticoid drops for patients whose symptoms had not resolved by one week [1]. The overall quality of the studies was low.
Selection among the different types of topics preparations depends upon the severity of disease and other factors such as the presence or absence of an intact tympanic membrane. (See 'Treating the infection' above.)
Antibiotics — Topical antibiotics are highly effective for treating AOE [9]. One systematic review found that topical antibiotics increased the AOE cure rate compared with placebo by 46 percent (95% CI 29-63 percent) [5]. There was no difference in cure rates between topical antibiotics and antiseptics or combination antibiotic/glucocorticoid preparations. There was also no difference between quinolone and nonquinolone antibiotics.
Certain factors should be considered when selecting an ototopical antibiotic; coverage of specific pathogens, side effect profile (including ototoxicity and risk of contact dermatitis), and cost.
The ideal antibiotic regimen should have coverage against the most common pathogens, S. aureus and P. aeruginosa:
●The topical fluoroquinolones ofloxacin and ciprofloxacin provide coverage against both pathogens. In two clinical trials, topical ofloxacin appeared to be as effective as topical neomycin-polymyxin B-hydrocortisone [10,11]. Another trial found that topical ciprofloxacin-dexamethasone was superior to topical neomycin-polymyxin B-hydrocortisone in decreasing inflammation, edema, and achieving pain control [12].
●Polymyxin B (a polypeptide antimicrobial) and neomycin (an aminoglycoside) are antibiotics that are combined in many frequently used ototopical medications (table 1). Polymyxin B is effective against P. aeruginosa, while neomycin is effective against S. aureus.
●Topical aminoglycosides (eg, tobramycin and gentamicin) are also effective against both S. aureus and P. aeruginosa.
While we generally prefer topical fluoroquinolones over other options for the treatment of otitis externa because of their antimicrobial spectrum, lack of potential ototoxicity, and lower risk of allergic reactions, they are more costly than other options and in the United States, insurance coverage is variable. Neomycin-polymyxin B-hydrocortisone is a reasonable alternative in ears with an intact TM.
Ototoxicity is the most important concern with aminoglycoside preparations, including neomycin, tobramycin, and gentamicin [13]. Aminoglycosides are a potential source of iatrogenic hearing loss and balance dysfunction, particularly in the presence of a non-intact TM. The risk of ototoxicity is greater with prolonged use, and manufacturer labeling suggests limiting the duration of topical neomycin-polymyxin B-hydrocortisone therapy to 10 consecutive days [14].
Allergic contact dermatitis is commonly associated with neomycin when used for prolonged courses [15]. Topical fluoroquinolones can cause local irritation. (See "Acute otitis externa in adults: Pathogenesis, clinical features, and diagnosis", section on 'Contact dermatitis'.)
Concerns have been raised about the development of antibiotic resistance, particularly against P. aeruginosa, with the chronic use of ototopical fluoroquinolones. However, in one study from 1996, in vitro P. aeruginosa sensitivity to norfloxacin remained high (98 percent) despite long-term use [16]. No other studies of AOE are available, but in a 2007 study of malignant otitis externa, 18.5 percent of Pseudomonas isolates were resistant to ciprofloxacin [17].
There is an increasing prevalence of methicillin-resistant S. aureus (MRSA) in AOE, with one center reporting that Pseudomonas accounted for 44 percent of isolates, methicillin-susceptible S. aureus 22 percent, and MRSA nearly 9 percent (of which one-third were resistant to fluoroquinolones) [18].
The significance of susceptibility testing for ototopical preparations in predicting clinical response is unclear, however. Susceptibility results pertain to antibiotic levels achieved with systemic administration, while topical application produces much higher local antibiotic levels [19]. This may account for the success in using topical antibiotics to treat AOE, although some the resistance of some isolates may not be overcome by high local antibiotic concentrations.
Glucocorticoids — Topical glucocorticoids decrease inflammation, resulting in relief of pruritus and improvement in pain. Some preparations used to treat AOE include hydrocortisone, dexamethasone, and prednisolone (table 1) [1]. They are generally well tolerated.
In a meta-analysis of randomized trials including three studies comparing topical antimicrobial with and without topical glucocorticoid therapy, there were comparable clinical and bacteriologic cure rates at seven days [5]. The addition of a hydrocortisone to either acetic acid or ciprofloxacin, however, decreased time to symptom resolution by one day.
Antiseptics and acidifying solutions — Antiseptics, such as alcohol and acetic acid (table 1), have broad-spectrum antimicrobial activity. Acidifying solutions inhibit bacterial growth; S. aureus and P. aeruginosa do not grow as well in environments with a pH <6 to 7 [20]. These agents are generally well tolerated but may be associated with local irritation manifested by burning or stinging. In the presence of TM perforation, however, alcohol and acidifying solutions should not be used as they can be particularly irritating to the mucosa of the middle ear. (See 'Nonintact tympanic membrane or unknown tympanic membrane status' above.)
Systemic reviews and meta-analyses, albeit including low-quality trials, suggest that these agents are comparably effective to other topical agents [1,5]. However, in one high-quality trial, acetic acid alone was less effective than acetic acid plus a glucocorticoid and an antibiotic plus a glucocorticoid at two and three weeks [21].
PAIN MANAGEMENT —
The pain from AOE is variable. Most patients with mild to moderate levels of ear pain will get prompt relief after initiation of topical therapy. Patients who require additional analgesia will generally respond to oral nonsteroidal antiinflammatory agents (NSAIDs) such as ibuprofen or naproxen, which can be started at the initial visit (see "NSAIDs: Therapeutic use and variability of response in adults"). Care should be exercised to ensure that pain medications are not masking inadequate treatment [7,22]. Clinicians should be especially concerned if a patient with diabetes being treated for AOE has persistent ear pain, as their diagnosis may be malignant otitis externa. (See "Necrotizing (malignant) external otitis".)
PATIENT COUNSELING
Installation of topical preparations — Correct application of topical agents to the site of infection is a key element in the effective treatment of AOE, regardless of severity. A common cause of failure for topical treatment is underdosing.
Proper installation of ear drops entails tilting the head toward the opposite shoulder, pulling the superior aspect of the auricle upward, and filling the ear canal with drops. Patients should ensure that sufficient medication is used to adequately fill the entire ear canal, typically 4 to 6 drops for an adult ear canal.
Patients should lie on their (opposite) side for three to five minutes following instillation or place a cotton ball in the ear canal for 20 minutes following instillation to maximize medicine exposure.
Ear hygiene during acute episode — The ear should be protected from water during treatment for AOE. During bathing or showering, patients can place a cotton ball coated with petroleum jelly in the ear canal. Patients with active AOE should not swim and ideally should refrain from water sports for 7 to 10 days. Competitive swimmers may consider return to swimming at two to three days if pain has resolved and they wear well-fitting ear plugs.
Hearing aids, "ear-buds," and other similar devices should not be worn until pain and discharge have subsided [7,22]. In addition, these devices should be disinfected prior to re-use.
Prevention of recurrence — Preventive interventions may be appropriate for patients with recurrent AOE, immunocompromised hosts, and patients with a dermatologic condition affecting the ear(s).
To prevent recurrence, patient education regarding proper ear hygiene is essential. Patients should be advised that the ear canal is self-cleaning, and that fingers, towels, cotton swabs, or other foreign objects should not be inserted into the canal.
AOE is a frequent occurrence in individuals who are habitually in the water [23]. Specific measures for those who engage in water sports include use of ear plugs, shaking the ear dry after swimming, and blow drying the ear after water exposure (placing the blow dryer on low speed and heat settings at least 12 inches away from the ears) [24].
Drops containing alcohol and/or acetic acid help to dry the ear, prevent skin maceration, and re-acidify the ear canal may be used, but it is unclear if this prevents recurrence of AOE.
Hearing aids should be removed nightly and cleaned regularly.
Clinical follow-up and indications for referral — Most patients with AOE will experience some symptom improvement within 36 to 48 hours after treatment is initiated, with full symptom resolution by about six days [1]. The timeframe for clinical follow-up depends upon the severity of AOE. Patients with mild AOE only need to return if symptoms persist or worsen beyond one week. For patients with moderate disease, follow-up is recommended at one to two weeks. Patients with severe disease may need to be seen sooner, typically within one week. (See 'Mild disease' above and 'Moderate disease' above and 'Severe disease' above.)
In patients who do not respond to initial treatment, the ear canal should be cultured [2]. Community-acquired methicillin-resistant S. aureus infection is one possible explanation for treatment failure [22]. The patient should be queried regarding medication adherence, adherence to water precautions, and avoidance of ear canal manipulation. AOE that fails to resolve despite appropriate antimicrobial treatment, those with unrelenting deep pain, and coexisting cranial nerve dysfunction or vertigo should raise suspicion for neoplasia of the auditory canal [25,26] or malignant otitis externa; such patients should be promptly referred to an otolaryngologist for further evaluation. Cranial nerve dysfunction warrants urgent referral.
All patients with diabetes or immunosuppression who have severe otitis externa or persistent unilateral ear pain may be at risk for malignant external otitis and should be referred to an otolaryngologist for further management. Clinical manifestations of malignant external otitis are discussed elsewhere. (See "Necrotizing (malignant) external otitis", section on 'Clinical manifestations'.)
Patients who do not respond to initial treatment should also be evaluated for other conditions that may mimic, complicate, or underlie AOE. (See "Acute otitis externa in adults: Pathogenesis, clinical features, and diagnosis", section on 'Differential diagnosis'.)
MANAGEMENT OF CONTRIBUTING OR SIMILAR CONDITIONS —
The treatment of other conditions that present similarly to or complicate bacterial AOE varies based upon the underlying etiology. They should be suspected in patients who fail to respond to initial therapy. (See "Acute otitis externa in adults: Pathogenesis, clinical features, and diagnosis", section on 'Differential diagnosis'.)
Otomycosis — Otomycosis is a fungal infection of the external auditory canal (picture 5); Aspergillus and Candida are the major pathogens. Otomycosis can occur as the primary infection or can develop along with bacterial AOE, usually as a result of antibiotic therapy. (See "Acute otitis externa in adults: Pathogenesis, clinical features, and diagnosis", section on 'Otomycosis'.)
The mainstay of therapy for otomycosis is meticulous cleaning of the ear canal and topical antifungal therapy [27]. All debris and visible fungal elements must be removed; this should be done by a clinician under direct visualization with a cerumen loop or cotton swab. Binocular magnified vision facilitates removal of debris that is often present in the medial aspect of the ear canal, coating the tympanic membrane (TM).
Several topical medications are used to treat otomycosis, including antifungals, antiseptics, acidifying solutions, and drying agents [27]. Although topical antifungals are considered first-line pharmacologic treatment [28], there are no dedicated otic antifungal preparations, and none have Food and Drug Administration (FDA) approval for treating otomycosis. In addition, information about potential ototoxicity of these agents is mostly limited to animal studies. Some antifungals are available in liquid form, and others only as a cream or ointment that is either injected into or swabbed into the ear canal.
For treatment of otomycosis in patients with an intact TM, we use clotrimazole 1% solution, applied twice daily into the ear canal for 10 to 14 days. The ototoxicity of topical clotrimazole in patients with non-intact TMs has not been studied in humans; in an experimental study of guinea pigs, clotrimazole appeared to be safe [29]. However, extrapolating from animal models to humans should be done with caution, and systemic antifungal therapy may be appropriate for patients with otomycosis and non-intact TMs.
Several studies have evaluated the efficacy of various topical antifungal agents in the treatment of otomycosis:
●In a randomized trial including 295 patients with otomycosis, participants were randomly assigned to treatment with 1% clotrimazole solution, miconazole cream, or fluconazole solution (concentration not reported); treatment efficacy was similar between all groups [30].
●In a randomized controlled trial including 138 patients with otomycosis, following initial debridement and instillation of a 2% acetic acid solution, patients were randomly assigned to receive sertaconazole 2% cream, miconazole 2% cream, clotrimazole 2% cream, or a placebo cream [31]. Outcomes were similar between all active treatment groups, and superior compared with placebo (88 to 95 versus 17 percent complete response after four weeks).
●In a randomized controlled trial including 48 patients with otomycosis, participants were randomly assigned to treatment with topical clotrimazole cream or topical tolnaftate solution [32]. At one week, clotrimazole was more effective in achieving clinical cure compared with tolnaftate (75 versus 45 percent, respectively).
●In a randomized controlled trial including 190 otomycosis patients in which participants were treated with eberconazole 1% otic solution or clotrimazole 1% solution, complete response rates were high and similar between both treatment groups (82 versus 84 percent, respectively) [33].
After 10 to 14 days of topical antifungal therapy, the ear canal should be reassessed. If there is evidence of ongoing inflammation or infection, the canal should be swabbed, and the material examined for fungal elements and submitted for culture. If fungal elements are identified, the ear canal should again be meticulously cleaned and undergo a further 10- to 14-day course of topical antifungal treatment with reassessment thereafter. Patients with persistent otomycosis should be referred to an otolaryngologist to ensure optimal cleaning of the external canal (usually with microscopic otoscopy). Ear cleaning followed by topical therapy and reassessment at two-week intervals may be required for several cycles to achieve eradication.
For patients with otomycosis that is refractory to topical therapy, or in patients who have a non-intact TM, systemic antifungal therapy may be used. Options include oral fluconazole to treat Candida infections (although some species are resistant) and oral voriconazole for Aspergillus and other susceptible molds. Clinicians should be aware that these systemic azoles have potential for hepatotoxicity and drug-drug interactions with other medications (see "Pharmacology of azoles"). In patients with invasive otomycosis (ie, malignant otitis externa due to molds), treatment with a systemic antifungal agent is necessary. Such patients should be managed in consultation with an infectious disease clinician. (See "Necrotizing (malignant) external otitis".)
Contact dermatitis — Contact dermatitis in the external auditory canal can be caused by ototopical medication, cosmetics, or shampoos and thus can mimic or complicate treatment for AOE. (See "Acute otitis externa in adults: Pathogenesis, clinical features, and diagnosis", section on 'Contact dermatitis'.)
Initial treatment of contact dermatitis involves eliminating the causative agent. The ear should be thoroughly cleaned by the clinician. Acidic solutions such as acetic acid otic help re-acidify the ear canal, dry weeping lesions, and debride crust. Topical glucocorticoids can be used in combination with acidic solutions to control the inflammatory response (table 1).
Malignant otitis externa — Malignant (necrotizing) otitis externa is a severe, potentially fatal complication of AOE. The infection begins in the ear canal, usually at the bony-cartilaginous junction, and then invades the deeper tissues, eventually leading to osteomyelitis of the skull base. Patients with malignant external otitis should have the ear canal cultured and then be promptly started on systemic antipseudomonal antibiotics. In addition, we advise urgent referral to otolaryngology and an infectious disease specialist. Rarely, invasive fungal external otitis can occur, and the clinician should keep this in mind if a patient fails to respond to antibacterial agents [34,35]. The clinical features, evaluation, and management of malignant external otitis is reviewed in detail elsewhere. (See "Necrotizing (malignant) external otitis".)
SOCIETY GUIDELINE LINKS —
Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Acute otitis media, otitis media with effusion, and external otitis".)
INFORMATION FOR PATIENTS —
UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: Outer ear infection (The Basics)" and "Patient education: Removing objects stuck in the ear (The Basics)")
●Beyond the Basics topics (see "Patient education: External otitis (including swimmer's ear) (Beyond the Basics)")
SUMMARY AND RECOMMENDATIONS
●Importance of cleaning the ear canal – Cleaning out the external ear canal under direct visualization is an essential first step in the treatment of AOE (also called external otitis or "swimmer's ear") in adult patients. Removal of cerumen, desquamated skin, and purulent material facilitates healing and enhances penetration of ear drops. (See 'Cleaning the ear canal' above.)
●Assess disease severity and tympanic membrane status – Treatment of AOE in adults depends on disease severity, whether the tympanic membrane (TM) is intact, and the presence of diabetes mellitus or immunocompromise (algorithm 1).
We assess severity as follows:
•Mild – Minor discomfort and pruritus, and minimal canal edema (picture 1).
•Moderate – Intermediate degree of pain and pruritus; the canal may be partially occluded (picture 2).
•Severe – Intense pain, and edema completely occludes the canal (picture 4). There may be periauricular erythema, regional lymphadenopathy, and/or fever.
In patients with diabetes or immunocompromise who present with severe otalgia and signs of granulation tissue in the external ear canal, malignant otitis externa should be considered. (See 'Management approach' above and "Necrotizing (malignant) external otitis".)
●Patients with intact TM and without cellulitis or fever – For immunocompetent adults with AOE with an intact TM and without associated cellulitis or fever, treatment depends on disease severity (algorithm 1).
•Mild disease – We suggest topical therapy with a combined antiseptic plus glucocorticoid (eg, acetic acid-hydrocortisone) rather than other agents (table 1) (Grade 2C).
•Moderate or severe disease – We suggest topical therapy with a combined fluoroquinolone plus glucocorticoid agent (eg, ciprofloxacin-hydrocortisone or ciprofloxacin-dexamethasone) rather than other agents. (table 1) (Grade 2C) because it is well tolerated and has appropriate broad-spectrum coverage, including against Pseudomonas aeruginosa and Staphylococcus aureus. Neomycin-polymyxin B-hydrocortisone is a reasonable alternative that is less costly, though it is associated with a greater risk of side effects.
If the ear canal is obstructed due to swelling, an aural wick should be placed to ensure delivery of ear drops to the inner ear canal.
For patients with severe disease, we obtain cultures of the ear canal drainage prior to initiation of treatment; results may help guide therapy.
We treat for one week, with instructions to continue topical therapy for an additional week if symptoms are not resolved. Symptoms persisting beyond two weeks or worsening at any time warrant reevaluation.
●AOE associated with cellulitis and/or fever – For immunocompetent adults with AOE that is associated with cellulitis and/or fever, we suggest therapy with both topical and systemic antibiotics rather than topical therapy alone (Grade 2C). Cultures of the ear canal drainage should be obtained prior to initiation of treatment. An aural wick may be needed to ensure delivery of ear drops to the inner ear canal if the ear canal is obstructed due to swelling.
Systemic antibiotic coverage should include coverage for S. aureus and P. aeruginosa.
-For patients with less severe cellulitis, we use an oral fluoroquinolone (eg, levofloxacin). For patients who are not candidates for systemic fluoroquinolones, acceptable alternatives include cefuroxime or amoxicillin-clavulanate although these options do not have activity against P. aeruginosa.
-For patients with more severe or rapidly progressing cellulitis, administration of intravenous (IV) antibiotics (eg, IV vancomycin plus IV cefepime) may be necessary until the infection is improving. The choice of oral antibiotic to complete the course of therapy can be guided by ear canal cultures results.
●AOE with nonintact TM or unknown TM status – The treatment of AOE with nonintact TM or if TM status is unknown (eg, unable to visualize) differs in terms of the preferred topical preparations and the recommendation for earlier referral to otolaryngology (ENT) if not responding to treatment (algorithm 1).
•Initial treatment – For adults with AOE (any degree of severity) and a nonintact TM, we suggest a seven-day course of a topical fluoroquinolone-containing treatment (eg, ciprofloxacin-dexamethasone, ciprofloxacin, ofloxacin) rather than other topical preparations (Grade 2C). Topical agents that contain aminoglycosides or alcohol and those with a low pH (table 1) should not be used in this setting due to risk of ototoxicity.
If there is associated cellulitis and/or fever, systemic antibiotic therapy is warranted in addition to topical therapy, as discussed above.
•Patients with an allergy to fluoroquinolones – For patients with a suspected or confirmed non-intact TM who cannot tolerate fluoroquinolones (eg, anaphylaxis, rash, systemic reaction, neurologic side effect, tendonitis), ear canal drainage should be cultured, and empiric treatment with an oral antibiotic (eg, cefuroxime 500 mg orally twice daily, or amoxicillin-clavulanate 875 mg orally twice daily) should be started. The patient should also be referred to ENT. If ear drainage culture in such a patient grows P. aeruginosa and the patient has not responded to the treatment given, a brief course of intravenous antibiotics with activity against the patient's P. aeruginosa isolate may be required in order to treat the infection.
•Refractory symptoms – In adults with persistent symptoms, we obtain a culture of the external drainage (if not already done), begin treatment with an oral antibiotic for one week, and refer to ENT for further management. (See 'Nonintact tympanic membrane or unknown tympanic membrane status' above.)
●Immunocompromised hosts – Regardless of the severity of infection, for all patients with immunosuppression and AOE, we suggest treatment with combined topical and systemic antibiotics rather than topical therapy alone (Grade 2C). For such patients, the preferred topical and systemic antibiotics are the same as those used for severe disease. All patients with diabetes or immunosuppression who have severe AOE or persistent unilateral ear pain may be at risk for malignant external otitis and should be referred to an otolaryngologist for further management (see 'Immunocompromised hosts' above and 'Severe disease' above and 'Clinical follow-up and indications for referral' above). Referral to an infectious diseases specialist may also be helpful.
●Patient counseling: Instillation of drops and ear hygiene – We provide education on the proper instillation of ear drops, and ear hygiene to employ during the acute episode and to prevent recurrence (table 2). Sufficient medication to adequately fill the entire ear canal should be used, typically 4 to 6 drops for an adult ear canal. Patients should lie on their (opposite) side for three to five minutes following instillation or place a cotton ball in the ear canal for 20 minutes following instillation. (See 'Installation of topical preparations' above.)
●Ear hygiene and prevention of recurrence – The ear should be protected from water during treatment for AOE. Hearing aids, "ear-buds," and other similar devices should not be worn until pain and discharge have subsided. These devices should be disinfected prior to reuse. To prevent recurrence, patient education regarding proper ear hygiene is essential. Specific measures for those who engage in water sports include using ear plugs, shaking the ear dry after swimming, and blow drying the ear after water exposure. (See 'Ear hygiene during acute episode' above and 'Prevention of recurrence' above.)
●Evaluation and management of contributing or similar conditions – Patients who do not respond to initial treatment should also be evaluated for other conditions that may mimic, complicate, or underlie AOE, including otomycosis, contact dermatitis, and malignant external otitis. (See 'Management of contributing or similar conditions' above.)
