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MerviStarck

Otitis Externa

Essentials

  • Topical treatment is used to manage both acute and chronic otitis externa; this consists of thorough cleaning of the external auditory canal (ear canal) and the application of ear drops or ointment.
  • The best treatment for chronic or recurrent otitis externa is prevention.
  • The patient should be given information regarding the causative and aggravating factors.
  • In persistent cases, the possibility of fungal infection, allergy, chronic skin disease and malignant tumours should be considered.
  • Remember the possibility of malignant otitis externa in a patient with general symptoms and suffering from pain, as well as in cases refractory to treatment.

Predisposing factors

  • Attempts at self-cleaning the ear canal
  • Swimming and/or dirty water entering the ear canal (acute otitis externa is common in the summer)
  • Hot and humid atmosphere (travel to hot climates)
  • Atopy and other allergies, seborrhoeic eczema, psoriasis and other skin conditions as well as diabetes
  • Chronic and, in some cases acute, otitis media
  • Otitis externa may also be associated with erysipelas and herpes zoster.

Causative organisms

  • Common causes of an acute infection are Pseudomonas aeruginosa and gram-positive cocci, such as Staphylococcus aureus. Chronic otitis externa is often caused by gram-negative rods (e.g. Pseudomonas aeruginosa) and occasionally by fungi, such as candida or aspergillus species8.
  • In chronic otitis externa, there is often no infection, but it is a case of inflammation.

Investigations

Clinical history

  • The duration and earlier occurrence of symptoms
  • The development of symptoms is often preceded by self-manipulation of the ear canal, other trauma, swimming or water entering the ear.
  • Past medical history of allergies, skin conditions and systemic diseases, such as diabetes
  • Any medicines and cosmetic preparations applied to the ear or its surroundings or foreign bodies in the ear canal can contribute towards the development of otitis externa 7.

Examination and clinical findings

  • See table T1
  • In acute otitis externa the ear is tender, sometimes painful, to touch3.
  • Particularly moving the auricle of the ear and pressing the tragus are painful.
  • To facilitate the examination and improve the effectiveness of treatment the ear canal should, if necessary, be carefully cleaned. Any debris is first physically removed, the ear canal is then irrigated with normal saline and dried with suction.
  • In acute otitis externa the meatal skin is erythematous, moist, oedematous and often has purulent discharge3. A small abscess may even be noted in the lateral part of the ear canal. The oedematous ear canal may make it impossible to view the tympanic membrane.
  • In fungal infection, the ear canal may have a mildewy appearance, or it may be covered by a grey-black spots or membrane7.
  • Pruritus is the principal symptom in chronic inflammation. The skin is often thickened and scaly.
    • Chronic otitis externa is often caused by a long-term skin disease such as eczema, psoriasis, contact dermatitis or, less commonly, lichen planus 3.
  • The state of the tympanic membrane should be established in order to exclude acute or chronic otitis media. The tympanic membrane must be checked at a follow-up appointment if this was not initially possible due to oedema.
  • Should the ear canal look normal, sources of the ear symptom, e.g. ear tenderness/pain, should be searched for elsewhere, for example in the temporomandibular joint or pharynx 10.

Signs, symptoms and treatment of acute and chronic otitis externa

Acute otitis externaChronic otitis externa
Symptom onsetFrom hours to days (duration less than 6 weeks)Duration over 6 weeks
Predisposing factorsManipulation of ears; water entering the ear; skin conditionsManipulation of ears; water entering the ear; skin conditions
Pain and pruritusMild to severe pain, pressing the tragus makes it worseNone or mild pain; pruritus
Meatal skinOedematous, erythematousScaly and sometimes thinned or thickened, sores and broken skin often present at the orifice of the ear canal
DischargePurulentNone or clear
Hearing impairmentMay be if there is a lot of discharge in the ear canal or the ear canal is very swollen Not usually
AnalgesiaNecessaryNot usually necessary
TreatmentAntimicrobial/glucocorticoid drops, in non-severe cases only an antisepticGlucocorticoid monotherapy either as drops or ointment, meatal skin care in non-severe cases
Sources: Rosenfeld 2014 10, Magliocca 2019 7, Smith 2021 3

Laboratory and imaging studies

  • Bacterial and fungal cultures are indicated if appropriate treatment does not relieve symptoms within 2-7 days, depending on the severity of the disease 3.
  • Differentiation between acute, fulminant otitis externa and acute mastoiditis can be difficult. However, in otitis externa there is no effusion in the middle ear. Computed tomography (CT) scanning of the ears may be considered in problematic cases.

Treatment

  • Otitis externa is not suitable for a remote appointment.
  • Scrupulous and atraumatic cleaning of the ear canal (aural toilet) http://www.dynamed.com/condition/otitis-externa#CLEANING_THE_EAR_CANAL, at first every 48-72 hours, is the cornerstone of the treatment. The ear canal should first be cleared of debris using microsuction, the ear is then irrigated with normal saline and finally dried using a suction. If the tympanic membrane is intact, normal saline mixed with surgical spirit may also be used as the irrigation fluid9.
  • High local concentrations of antibiotics are achieved with ear drops without systemic adverse effects. The treatment is continued for 7-10 days.
  • A ribbon gauze dressing or expanding ear wick soaked with topical medication can be placed into a severely oedematous ear canal. Ear drops are administered directly into the wick which is changed every 48-72 hours until the ear canal reopens6.
  • Healing of severe otitis externa should be checked within 48-72 hours of the start of treatment 106.
  • An abscess within the ear canal should be incised, for example with a myringotomy scalpel under local anaesthesia.
  • A patient with otitis externa needs effective analgesic medication.

Ototopical preparations

Systemic medication

Recurrent or chronic inflammation

  • The patient should be told to avoid inserting any objects into the ear canal since it causes mechanical damage to the skin and microbiome alterations 4.
  • Pruritus can be managed with glucocorticoid ointment or drops.
  • In otitis externa care should be taken to avoid water entering the ear canal. Patients prone to otitis externa should always follow this precaution.
    • For water protection, plugs made for the patient's ear or, for example, lubricated cotton can be used.

Indications for specialist consultation

  • Severe local pain, unsuccessful attempts at aural toilet, systemic symptoms or inflammation spreading outside the ear canal11
  • Diabetes, immunodeficiency and advanced age predispose to malignant or necrotizing otitis externa http://www.dynamed.com/condition/malignant-otitis-externa which is an invasive infection spreading to the temporal bone and skull base most commonly caused by pseudomonas 2.
    • A severely symptomatic patient with one of the aforementioned illnesses should be referred to specialized care as an emergency case. 1
  • Otitis externa associated with abnormal tissue formation
  • Chronic or recurrent infection despite microbiological studies and treatment attempts
  • Unilateral otitis externa, particularly in an elderly patient, may be a sign of a malignant tumour.

    References

    • Tsilivigkos C, Avramidis K, Ferekidis E, et al. Malignant External Otitis: What the Diabetes Specialist Should Know-A Narrative Review. Diabetes Ther 2023;14(4):629-638. [PubMed]
    • Arslan IB, Pekcevik Y, Cukurova I. Management and long-term comorbidities of patients with necrotizing otitis externa. Eur Arch Otorhinolaryngol 2023;280(6):2755-2761. [PubMed]
    • Smith ME, Hardman JC, Mehta N, et al. Acute otitis externa: Consensus definition, diagnostic criteria and core outcome set development. PLoS One 2021;16(5):e0251395. [PubMed]
    • Sjövall A, Aho VTE, Hyyrynen T, et al. Microbiome of the Healthy External Auditory Canal. Otol Neurotol 2021;42(5):e609-e614. [PubMed]
    • Lee A, Tysome JR, Saeed SR. Topical azole treatments for otomycosis. Cochrane Database Syst Rev 2021;5(5):CD009289. [PubMed]
    • Wiegand S, Berner R, Schneider A, et al. Otitis Externa. Dtsch Arztebl Int 2019;116(13):224-234. [PubMed]
    • Magliocca KR, Vivas EX, Griffith CC. Idiopathic, Infectious and Reactive Lesions of the Ear and Temporal Bone. Head Neck Pathol 2018;12(3):328-349. [PubMed]
    • Heward E, Cullen M, Hobson J. Microbiology and antimicrobial susceptibility of otitis externa: a changing pattern of antimicrobial resistance. J Laryngol Otol 2018;132(4):314-317. [PubMed]
    • Hajioff D, MacKeith S. Otitis externa. BMJ Clin Evid 2015;2015():. [PubMed]
    • Rosenfeld RM, Schwartz SR, Cannon CR, et al. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg 2014;150(1 Suppl):S1-S24. [PubMed]
    • Guevara N, Mahdyoun P, Pulcini C, et al. Initial management of necrotizing external otitis: errors to avoid. Eur Ann Otorhinolaryngol Head Neck Dis 2013;130(3):115-21. [PubMed]