Central Annals of Otolaryngology and Rhinology

Cite this article: Treviño González JL, Moreno KD (2017) Otitis Externa: And Update. Ann Otolaryngol Rhinol 4(8): 1195.

*Corresponding author

Jose Luis Treviño González, Av. Madero y Gonzalitos Colonia Mitras Centro, Monterey, México, Tel: 83334846; Email:

Submitted: 20 September 2017

Accepted: 24 October 2017

Published: 26 October 2017

ISSN: 2379-948X

Copyright© 2017 Treviño González et al.

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Keywords•Acute otitis externa•Treatment guideline•Otitis externa maligna•Drug resistance

Review Article

Otitis Externa: And UpdateJosé Luis Treviño González* and Karla Durán MorenoDepartment of Otolaryngology and Head and Neck Surgery, School of Medicine, University A. of Nuevo León, México

Abstract

Acute otitis externa is the inflammation and infection of the external auditory canal. The acute form can be classified as diffuse otitis externa, which is the most common form of OE, and localized otitis externa. This pathology occurs primarily in swimmers because of the prolonged exposure to water, but it can also be caused by minor traumas in an inappropriate cleaning. Pseudomonas aeruginosa and Staphylococcus aureus are the most common pathogens found in AOE.

Signs and symptoms include otalgia, itching, canal edema, erythema and otorrhea. The most significant sign is soreness of the tragus with movement.

Diagnosis is clinical with help of an otoscope to have a direct and clearer view.

For the management of acute otitis externa, a combination of measures is necessary. The most important step is an exhaustive cleaning or aspiration of the ear canal, so there is a correct penetration of the drug therapy.

Treatment for AOE involves acidifying agents alone, acidifying agents with steroids, or antibiotics with steroids. This last one is the most recommended treatment, being Ciprofloxacin the first line of treatment in antibiotics.

ABBREVIATIONSAOE: Acute Otitis Externa; EAC:External Auditory Canal; OE:

Otitis Externa

INTRODUCTIONAcute otitis externa is a condition that involves inflammation

of the external ear canal which may extend laterally to the pinna and proximally to the tympanic membrane resulting in otalgia, itching, canal edema, erythema and otorrhea. Soreness with movement of the tragus or pinna is a classic finding.

This pathology often occurs after swimming or minor trauma from inappropriate cleaning. Local defense mechanisms become disabled by prolonged ear canal wetness, and skin desquamation leads to microscopic fissures that provide a portal of entry for infecting organisms. The acute diffuse form, which is this review main issue, is caused primarily by bacterial infection, with Pseudomonas aeruginosa and Staphylococcus aureus as the most common pathogens [1,2].

Each year, otitis externa is reported to affect four out 1000 Americans of all age groups, and it affects males and females equally. The incidence is highest in children. A study from US reported that from 2003 to 2007, rates of ambulatory visits for otitis externa were highest among children 5-9 years and 10-14 years [3,4].

Classification

Acute otitis externa can be classified based on its etiology,

location and time course of illness. These include acute diffuse otitis externa, which is the main subject in this review, acute localized otitis externa, otomycosis, herpes oticus, dermatoses and malignant otitis externa [5].

Microbiology

The bacterial flora of the EAC is predominantly composed of gram positive organisms. The most commonly recognized microorganisms are Staphylococcus epidermidis (38%) and Diptheroid (22.4%). Gram negative organisms are less prevalent, isolated from <5% of the external auditory canal specimens. Following prolonged water exposure, however, the flora of the EAC changes, becoming dominated by gram negative organisms.

Pseudomonas aeruginosa is the most frequent pathogen in AOE, identified in 22-62% of cases in series on AOE. Staphylococcus aureus (11-34% of cases) is the most important gram positive pathogen [5-8].

Risk factors

There are several factors that can cause AOE, one of them being associated with dermatological disease of the ear canal and conchal bowl, such as eczema and, less commonly, psoriasis. These abnormalities are more common in swimmers, humid environments, in people with narrow external ear canals, in hearing aid users, and after mechanical trauma or ear syringing [9-11]. Otitis externa may also occur secondary to ear canal obstruction by impacted cerumen, foreign object, a dermoid cyst, sebaceous cyst, or furuncle [12].

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Diagnosis

The diagnosis of AOE is primarily clinical. The clinical history should identify predisposing factors including exposure to potentially contaminated water or mild trauma from inappropriate cleaning.

Symptoms include otalgia (70%), itching (60%), or fullness (22%), with or without hearing loss (32%) or ear canal pain on chewing. A hallmark sign of diffuse AOE is tenderness of the tragus, the pinna, or both, when manipulated [12].

Otoscopy will reveal diffuse ear canal edema, erythema, with or without otorrhea. Regional lymphadenitis or cellulitis of the pinna and adjacent skin may be present in some patients [12].

Apart from the typical acute form of otitis externa, special forms can appear such as an acute localized otitis externa, which originates from a hair follicle, or otitis externa necroticans (“maligna”), which can take a fulminant course and therefore requires intravenous treatment [13].

Treatment

There are 5 fundamental steps in the management of external otitis: cleaning the ear canal, treat inflammation and infection, control pain, avoid promoting factors, and follow up [14].

The most important step in treating an AOE is an exhaustive, gentle cleansing, suction and instrumentation of the external auditory canal under direct microscopic inspection. This facilitates healing and enhances penetration of ear drops into the site of inflammation.

Sometimes the debris is hard, crusted and difficult to take out, in those cases, topical otic drops or hydrogen peroxide can help softening the canal’s content. The frequency of canal cleansing depends on the amount of debris and secretion, and may vary from once every 1 to 5 days [15].

Once the external auditory canal is clean, the next step is the topical drug therapy. A topical approach is considered to be better than oral antibiotics or surgery, because the disease is limited to the skin of the ear canal. The treatment includes acidifying agents, and topical antibiotics. Topical corticosteroids and non steroidal anti-inflammatory drugs can also be employed, to assist in the resolution of the local edema and pain relief [15].

Acidifying solutions (Antiseptics)

Antiseptics function as bacteriostatic agents; they make the ear canal less habitable for bacteria and may loosen debris in the ear canal. P. aeruginosa and S. aureus, which are the most common pathogens, need an optimal pH between 6.5 and 7.3 in the ear canal to have perfect growing conditions, they do not grow well in a lower pH. That’s why by simply acidifying the ear canal, bacterial growth inhibition occurs. Some of the antiseptics used are aluminium acetate and acetic acid 2%.

Acidifying solutions are well tolerated, but may be associated with local irritation manifested by burning or stinging. Acetic acid can be applied as monotherapy or it can be combined with steroids, such as hydrocortisone, when managing an uncomplicated AOE [16].

Topical antibiotics

When there is a moderate to severe form of otitis externa, the current gold standard treatment is topical antibiotics in the form of ear drops, which may also contain topical steroids. Sometimes the auditory canal is occluded and needs an ear wick insertion, which can be gauze, or aperformed cellulose sponge, to help the canal expand and have an appropriate penetration of the topical solution. When indicated, a return visit in two to three days for removal of the wick is necessary [17].

Certain factors should be considered when selecting an ototopical antibiotic: coverage of specific pathogens, side effect profile, and drug resistance.

The ideal antibiotic regimen should have specific coverage against the most common pathogens, P. Aeruginosa and S. aureus. For example fluoroquinolones like ofloxacin and ciprofloxacin provide excellent coverage against both pathogens, as well as aminoglycosides, tobramycin and gentamicin.

Ciprofloxacin ranks among the most effective fluoroquinolone against P. aeruginosa; it has a broad spectrum and acts as a bactericide, particularly against gram negative pathogens, and is moderately effective against gram positive pathogens. Topical ciprofloxacin constitutes the first line of treatment in severe otitis externa in children and adolescents [18].

Concerning the side effect profile, ototoxicity is the most important concern with aminoglycoside agents. There is a significant potential source for iatrogenic hearing loss and balance dysfunction, particularly in the presence of tympanic membrane perforation. Allergic contact dermatitis is commonly associated with neomycin when used for prolonged courses [19].

Contrariwise, the side effect of fluoroquinolones is local irritation, and there is no risk of ototoxicity [19].

Inflammation and pain control

Adequate pain control for mild to moderate AOE can be achieved with sistemic acetaminophen, non steroidal anti-inflammatory medications or oral opioid preparations. Topical steroids preparations have mixed effects on hastening pain relief but are not recommended as monotherapy [20,21].

Studies showed significant improvement with steroid and antibiotic combination when compared with only antibiotic drops [22].

Drug resistance

There is certain concern that some patients develop a drug resistant form of otitis externa. This resistance is more common in infections caused by bacterial (66%) and fungal (15%) microorganisms. The most common pathogens are Pseudomonas species and S. Aureus. In a prospective study, it was observed 100% resistance of Pseudomonas species to neomycin, chloramphenicol, trimethoprim and amoxicillin, while all isolates were sensitive to polymyxin B and ciprofloxacin. Sensitivity to gentamicin was 98.5%. S. Aureus isolates showed no evidence of resistance to gentamicin and flucloxacillin. 92.3% of isolates were sensitive to neomycin and chloramphenicol. In view of this, polymyxin B, gentamicin or ciprofloxacin topical preparations should be used as first line treatment for otitis externa in secondary care [23,24].

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Treviño González JL, Moreno KD (2017) Otitis Externa: And Update. Ann Otolaryngol Rhinol 4(8): 1195.

Cite this article

DISCUSSION & CONCLUSIONAcute otitis externa is a frequent health problem in young

ages and there are many factors that can avoid the development of this disease, especially if physicians dedicate time to educate patients in how to avoid recurrences of AOE. The most important issue is to avoid complications, which are not that frequent but can be deadly.

The correct management of diffuse external otitis is simple, and as mentioned in the review, topical preparations such as ciprofloxacin make it easier to avoid side effects and give a more complete and effective therapy.

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