Your activity: 4 p.v.

External otitis: Treatment

External otitis: Treatment
Authors:
Laura A Goguen, MD
Marlene L Durand, MD
Section Editors:
Daniel G Deschler, MD, FACS
Morven S Edwards, MD
Deputy Editor:
Jane Givens, MD, MSCE
Literature review current through: Dec 2022. | This topic last updated: Jul 13, 2022.

INTRODUCTION — External otitis, also known as otitis externa or swimmer's ear, refers to inflammation of the external auditory canal or auricle.

This topic will focus on the treatment of external otitis. The pathogenesis, clinical manifestations, and diagnosis of external otitis are discussed elsewhere. (See "External otitis: Pathogenesis, clinical features, and diagnosis".)

Malignant external otitis, 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 "Malignant (necrotizing) external otitis".)

(See "Acute otitis media in adults".)

(See "Chronic otitis media, cholesteatoma, and mastoiditis 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 an otolaryngologist 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 upon the severity of the external otitis, the presence of diabetes mellitus or immunocompromise, and the presence or absence of an intact tympanic membrane (TM).

Mild disease is characterized by minor discomfort and pruritus. There is minimal canal edema (picture 1).

Moderate disease is characterized by an intermediate degree of pain and pruritus. The canal may be partially occluded (picture 2).

Severe disease is characterized by intense pain, and on examination, the canal is completely occluded from edema. Auricular and/or periauricular cellulitis, regional lymphadenopathy, and fever may also be present (picture 3).

Intact tympanic membrane — The treatment of mild to moderate external otitis in immunocompetent patients with an intact TM is with topical medications [2].

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 otitis externa. (See "External otitis: 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 otitis externa.

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 — For patients with mild external otitis 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 non-antibiotic 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 have not resolved. Patients with mild disease and symptoms persisting beyond two weeks should be reevaluated for treatment failure.

Moderate disease — For patients with moderate disease and an intact TM, we suggest treatment with a combination topical preparation that is acidic and 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 and neomycin-polymyxin B-hydrocortisone are preferred first-line agents. We generally treat with ciprofloxacin-hydrocortisone; although it is more costly, it is 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 have not resolved. Patients with moderate disease and symptoms persisting after one to two weeks should be reevaluated for treatment failure.

Severe disease — 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 fail to respond to empiric therapy.

For severe external otitis, we suggest treatment with an acidic 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 and neomycin-polymyxin B-hydrocortisone are good first-line agents. We generally prefer ciprofloxacin-hydrocortisone; although it is more costly, it is 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 topical preparations containing aminoglycosides, and acidifying agents should be avoided due to potential ototoxicity. (See 'Non-intact (perforated) tympanic membrane' below.)

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 an otolaryngologist but can also be performed by a primary care practitioner with experience in the procedure.

Most topical preparations should be administered three to four times daily, although topical fluoroquinolones can be given twice daily.

For patients who have severe external otitis with preauricular or auricular cellulitis and/or fever, 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 upon the severity of the infection beyond the ear canal:

For patients with less severe infection, an oral fluoroquinolone (such as levofloxacin 500 mg orally once daily for seven days) may be given [5]. 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, are options for methicillin-susceptible S. aureus.

For patients with more severe infection, 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.

We prescribe an initial seven-day course of topical medication, with additional treatment possible depending on response to initial therapy. Patients with severe external otitis 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.

For any patient with diabetes or immunocompromise, unilateral ear pain, and inflammation in the external ear canal, malignant otitis externa should be considered. The approach to diagnosing and treating this more serious infection is detailed in a separate topic. (See "Malignant (necrotizing) external otitis", section on 'Systemic antimicrobial therapy'.)

Non-intact (perforated) tympanic membrane — The treatment of patients with a non-intact TM (eg, ruptured TM, tympanostomy tubes) is similar to patients with an intact TM, with the exception of the preferred topical preparations.

In patients with external otitis and a suspected or confirmed non-intact TM, ototoxic preparations containing aminoglycosides or alcohol, as well as acidic preparations, should not be given since they may reach the middle ear. For such patients, we suggest treatment with a topical fluoroquinolone (eg, ciprofloxacin-dexamethasone, ciprofloxacin, ofloxacin) rather than other topical preparations (table 1). Topical preparations that reach the middle ear through a disrupted TM can also reach the round window and cause significant ototoxicity, potentially affecting hearing and/or balance. Topical agents that contain aminoglycosides or alcohol, or that have a low pH, should be avoided due to potential pain and ototoxicity [6]. Other topical otic antibiotics or antiseptics are either known to be ototoxic when they reach the middle ear, or their safety has not been established [7]. Our approach is consistent with the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) [6].

In patients with external otitis and a non-intact TM who cannot tolerate a topical fluoroquinolone or who do not respond to this treatment, a course of oral antibiotics may be warranted. Cultures of the ear canal material should be obtained as these results can help guide therapy. Initial empiric treatment with either levofloxacin 500 mg orally once daily (preferred for Pseudomonas), cefuroxime 500 mg orally twice daily, or amoxicillin-clavulanate 875 mg orally twice daily for one week are options; antibiotic selection can be modified when culture results are available.

Immunocompromised hosts — Regardless of the severity of infection, for all patients with immunosuppression and external otitis, 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 external otitis refractory to therapy (eg, persistent ear drainage or pain) should be referred to an otolaryngologist for further management of the external otitis and evaluation for malignant otitis externa. (See "Malignant (necrotizing) external otitis".)

Topical otic preparations: General principles — Topical therapy delivers a high concentration of medication to the infected and inflamed external tissue with few side effects [1,6,8]. 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 external otitis [9]. One systematic review found that topical antibiotics increased the external otitis cure rate compared with placebo by 46 percent (95% CI 29-63 percent) [6]. 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 "External otitis: 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 external otitis 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 acute otitis externa, 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 external otitis, 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 external otitis 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 [6]. 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 'Non-intact (perforated) tympanic membrane' above.)

Systemic reviews and meta-analyses, albeit including low-quality trials, suggest that these agents are comparably effective to other topical agents [1,6]. 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 external otitis 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 [5,22]. Clinicians should be especially concerned if a patient with diabetes being treated for external otitis has persistent ear pain, as their diagnosis may be malignant otitis externa. (See "Malignant (necrotizing) 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 external otitis, 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. In young children, the earlobe should be pulled downward in order to adequately fill the 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 external otitis. During bathing or showering, patients can place a cotton ball coated with petroleum jelly in the ear canal. Patients with active external otitis 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 [5,22]. In addition, these devices should be disinfected prior to re-use.

Prevention of recurrence — Preventive interventions may be appropriate for patients with recurrent external otitis, 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.

External otitis 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 external otitis.

Hearing aids should be removed nightly and cleaned regularly.

Clinical follow-up and indications for referral — Most patients with otitis external 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 external otitis. Patients with mild external otitis 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. External otitis 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 "Malignant (necrotizing) 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 external otitis. (See "External otitis: 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 external otitis varies based upon the underlying etiology. They should be suspected in patients who fail to respond to initial therapy. (See "External otitis: Pathogenesis, clinical features, and diagnosis", section on 'Differential diagnosis'.)

Otomycosis — Otomycosis is a fungal infection of the external auditory canal (picture 4); Aspergillus and Candida are the major pathogens. Otomycosis can occur as the primary infection or can develop along with bacterial external otitis, usually as a result of antibiotic therapy. (See "External otitis: 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 "Malignant (necrotizing) 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 external otitis. (See "External otitis: 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 external otitis — Malignant (necrotizing) external otitis is a severe, potentially fatal complication of acute external otitis. 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 "Malignant (necrotizing) 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 is an essential first step in the treatment of external otitis. The removal of cerumen, desquamated skin, and purulent material greatly facilitates healing and enhances penetration of ear drops into the site of inflammation. (See 'Cleaning the ear canal' above.)

Approach to treatment- Our approach to treatment depends on the severity of the external otitis, the presence of diabetes mellitus or immunocompromise, and the presence or absence of an intact tympanic membrane (TM). (See 'Management approach' above.)

Intact tympanic membrane

-Mild external otitis – Mild external otitis is characterized by minor discomfort and pruritus, and minimal canal edema (picture 1). For immunocompetent patients with mild disease and an intact TM, we suggest treatment with a non-antibiotic topical preparation containing an acidifying agent and a glucocorticoid (eg, acetic acid-hydrocortisone) rather than other agents (table 1) (Grade 2C). We treat for one week, with instructions to continue for an additional week if symptoms have not resolved. Symptoms persisting beyond two weeks warrant reevaluation. (See 'Mild disease' above.)

-Moderate external otitis – Moderate external otitis is characterized by an intermediate degree of pain and pruritus, and the canal may be partially occluded (picture 2). For immunocompetent patients with moderate disease and an intact TM, we suggest treatment with a topical preparation that is acidic, contains an antibiotic with coverage against Pseudomonas aeruginosa and Staphylococcus aureus, an antiseptic, and a glucocorticoid rather than other topical preparations (table 1) (Grade 2C). We prefer ciprofloxacin-hydrocortisone; although it is more costly, it is associated with fewer side effects than neomycin-polymyxin B-hydrocortisone. We treat for one week, with instructions to continue for an additional week if symptoms have not resolved. Symptoms persisting after one to two weeks warrant reevaluation. (See 'Moderate disease' above.)

-Severe external otitis – Severe external otitis is characterized by intense pain, and the canal is completely occluded from edema (picture 3). There may be fever, periauricular or auricular cellulitis, regional lymphadenopathy, and/or fever. Cultures of the ear canal drainage should be obtained; the results may help guide therapy, particularly in patients who fail to respond to empiric therapy.

For immunocompetent patients with severe disease and an intact TM, we suggest treatment with a topical preparation that is acidic and contains an antibiotic with coverage against P. aeruginosa and S. aureus and a glucocorticoid rather than other preparations (table 1) (Grade 2C). We prefer ciprofloxacin-hydrocortisone; although it is more costly, it is associated with fewer side effects than neomycin-polymyxin B-hydrocortisone.

Patients with canal obstruction due to swelling require wick placement. A wick allows topical medications to reach the medial aspect of the ear canal and can also facilitate longer retention of the topical solution.

For patients who have severe disease with preauricular or auricular cellulitis and/or fever, we suggest dual therapy with both topical and systemic antibiotics rather than topical therapy alone (Grade 2C). Systemic treatment with a fluoroquinolone (such as levofloxacin 500 mg orally once daily for seven days) for coverage of S. aureus and P. aeruginosa is preferred. 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 option for methicillin-susceptible S. aureus. Intravenous (IV) antibiotics are be indicated for patients with more extensive infection.

Patients with severe external otitis 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 seen within three days to change the wick (if applicable) and to assess response to treatment. (See 'Severe disease' above.)

Non-intact TM

-The treatment of patients with a non-intact TM is similar to that in patients with an intact TM, with the exception of the preferred topical preparations. In patients with external otitis and a known or suspected non-intact TM, we suggest treatment with a topical fluoroquinolone (eg, ciprofloxacin-dexamethasone, ciprofloxacin, ofloxacin) rather than other preparations (Grade 2C). Topical agents that contain aminoglycosides or alcohol, or that have a low pH (table 1), should not be given due to potential pain and ototoxicity. (See 'Non-intact (perforated) tympanic membrane' above.)

In patients with moderate external otitis and a non-intact TM who cannot tolerate a topical fluoroquinolone or who do not respond to this treatment, a course of oral antibiotics (eg, levofloxacin 500 mg orally once daily, cefuroxime 500 mg orally twice daily, or amoxicillin-clavulanate 875 mg orally twice daily for one week) may be warranted. It should be noted that of these options, only levofloxacin has activity against Pseudomonas.

Immunocompromised hosts – Regardless of the severity of infection, for all patients with immunosuppression and external otitis, 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 external otitis 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.)

Correct instillation of topical preparation – Correct application of topical agents is a key element in the effective treatment of external otitis. 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 external otitis. 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 external otitis, including otomycosis, contact dermatitis, and malignant external otitis. (See 'Management of contributing or similar conditions' above.)

  1. Kaushik V, Malik T, Saeed SR. Interventions for acute otitis externa. Cochrane Database Syst Rev 2010; :CD004740.
  2. Llor C, McNulty CA, Butler CC. Ordering and interpreting ear swabs in otitis externa. BMJ 2014; 349:g5259.
  3. Yelland MJ. The efficacy of oral cotrimoxazole in the treatment of otitis externa in general practice. Med J Aust 1993; 158:697.
  4. Roland PS, Belcher BP, Bettis R, et al. A single topical agent is clinically equivalent to the combination of topical and oral antibiotic treatment for otitis externa. Am J Otolaryngol 2008; 29:255.
  5. Santos F, Selesnick SH, Gurnstein E. Diseases of the external ear. In: Current Diagnosis and Treatment in Otolaryngology: Head and Neck Surgery, Lalwani AK (Ed), Lange Medical Books/McGraw-Hill, 2004.
  6. Rosenfeld RM, Singer M, Wasserman JM, Stinnett SS. Systematic review of topical antimicrobial therapy for acute otitis externa. Otolaryngol Head Neck Surg 2006; 134:S24.
  7. Noonan KY, Saunders JE. External otologic infections. In: Infections of the Ears, Nose, Throat, and Sinuses, Durand ML, Deschler DG (Eds), Springer International Publishing, 2018. p.101.
  8. Rosenfeld RM, Schwartz SR, Cannon CR, et al. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg 2014; 150:S1.
  9. Rosenfeld RM, Brown L, Cannon CR, et al. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg 2006; 134:S4.
  10. Jones RN, Milazzo J, Seidlin M. Ofloxacin otic solution for treatment of otitis externa in children and adults. Arch Otolaryngol Head Neck Surg 1997; 123:1193.
  11. 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 2006; 22:1725.
  12. Roland PS, Younis R, Wall GM. A comparison of ciprofloxacin/dexamethasone with neomycin/polymyxin/hydrocortisone for otitis externa pain. Adv Ther 2007; 24:671.
  13. Roland PS, Stewart MG, Hannley M, et al. Consensus panel on role of potentially ototoxic antibiotics for topical middle ear use: Introduction, methodology, and recommendations. Otolaryngol Head Neck Surg 2004; 130:S51.
  14. Corisporin otic solution [package insert]. Pfizer Laboratories. Available at: https://www.pfizermedicalinformation.com/en-us/cortisporin-otic-solution?section=warnings (Accessed on September 30, 2020).
  15. Van Ginkel CJ, Bruintjes TD, Huizing EH. Allergy due to topical medications in chronic otitis externa and chronic otitis media. Clin Otolaryngol Allied Sci 1995; 20:326.
  16. Dohar JE, Kenna MA, Wadowsky RM. In vitro susceptibility of aural isolates of Pseudomonas aeruginosa to commonly used ototopical antibiotics. Am J Otol 1996; 17:207.
  17. Franco-Vidal V, Blanchet H, Bebear C, et al. Necrotizing external otitis: a report of 46 cases. Otol Neurotol 2007; 28:771.
  18. Duarte MJ, Kozin ED, Bispo PJM, et al. Methicillin-resistant Staphylococcus aureus in acute otitis externa. World J Otorhinolaryngol Head Neck Surg 2018; 4:246.
  19. Walker DD, David MZ, Catalano D, et al. In Vitro Susceptibility of Ciprofloxacin-Resistant Methicillin-Resistant Staphylococcus aureus to Ototopical Therapy. Otolaryngol Head Neck Surg 2018; 158:923.
  20. Kim JK, Cho JH. Change of external auditory canal pH in acute otitis externa. Ann Otol Rhinol Laryngol 2009; 118:769.
  21. van Balen FA, Smit WM, Zuithoff NP, Verheij TJ. Clinical efficacy of three common treatments in acute otitis externa in primary care: randomised controlled trial. BMJ 2003; 327:1201.
  22. Styers D, Sheehan DJ, Hogan P, Sahm DF. Laboratory-based surveillance of current antimicrobial resistance patterns and trends among Staphylococcus aureus: 2005 status in the United States. Ann Clin Microbiol Antimicrob 2006; 5:2.
  23. Wingelaar TT, van Ooij PA, van Hulst RA. Otitis externa in military divers: more frequent and less harmful than reported. Diving Hyperb Med 2017; 47:4.
  24. Osguthorpe JD, Nielsen DR. Otitis externa: Review and clinical update. Am Fam Physician 2006; 74:1510.
  25. Zhang T, Dai C, Wang Z. The misdiagnosis of external auditory canal carcinoma. Eur Arch Otorhinolaryngol 2013; 270:1607.
  26. McCullough WP, Pollock AN. Langerhans Cell Histiocytosis Presenting as Chronic Otitis Externa. Pediatr Emerg Care 2017; 33:67.
  27. Vennewald I, Klemm E. Otomycosis: Diagnosis and treatment. Clin Dermatol 2010; 28:202.
  28. Munguia R, Daniel SJ. Ototopical antifungals and otomycosis: a review. Int J Pediatr Otorhinolaryngol 2008; 72:453.
  29. Tom LW. Ototoxicity of common topical antimycotic preparations. Laryngoscope 2000; 110:509.
  30. Navaneethan N, YaadhavaKrishnan RP. Type of Antifungals: Does it Matter in Empirical Treatment of Otomycosis? Indian J Otolaryngol Head Neck Surg 2015; 67:64.
  31. Nemati S, Gerami H, Faghih Habibi A, et al. Sertaconazole versus Clotrimazole and Miconazole Creams in the Treatment of Otomycosis: A Placebo-Controlled Clinical Trial. Iran J Otorhinolaryngol 2022; 34:27.
  32. Jimenez-Garcia L, Celis-Aguilar E, Díaz-Pavón G, et al. Efficacy of topical clotrimazole vs. topical tolnaftate in the treatment of otomycosis. A randomized controlled clinical trial. Braz J Otorhinolaryngol 2020; 86:300.
  33. de la Paz Cota BR, Cepero Vega PP, Matus Navarrete JJ, et al. Efficacy and safety of eberconazole 1% otic solution compared to clotrimazole 1% solution in patients with otomycosis. Am J Otolaryngol 2018; 39:307.
  34. Bowles PF, Perkins V, Schechter E. Fungal malignant otitis externa. BMJ Case Rep 2017; 2017.
  35. Marchionni E, Parize P, Lefevre A, et al. Aspergillus spp. invasive external otitis: favourable outcome with a medical approach. Clin Microbiol Infect 2016; 22:434.
Topic 16516 Version 38.0

References