Other presentations
Necrotizing otitis externa (also called malignant otitis externa) is a form of otitis externa that is more common in older patients with uncontrolled diabetes or in patients with immunodeficiency.[1]Rosenfeld RM, Schwartz SR, Cannon CR, et al. American Academy of Otolaryngology-Head and Neck Surgery Foundation. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg. 2014 Feb;150(1 suppl):S1-24. [Erratum in: Otolaryngol Head Neck Surg. 2014 Mar;150(3):504].
https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599813517083
http://www.ncbi.nlm.nih.gov/pubmed/24491310?tool=bestpractice.com
[4]Lee SK, Lee SA, Seon SW, et al. Analysis of prognostic factors in malignant external otitis. Clin Exp Otorhinolaryngol. 2017 Sep;10(3):228-35.
https://www.e-ceo.org/journal/view.php?id=10.21053/ceo.2016.00612
http://www.ncbi.nlm.nih.gov/pubmed/27671716?tool=bestpractice.com
In necrotizing otitis externa, the infection and the inflammatory process involve not only the skin and soft tissue of the external auditory canal but also the bone tissue of the temporal bone.[5]Walshe P, Cleary M, McConn WR, et al. Malignant otitis externa: a high index of suspicion is still needed for diagnosis. Irish Med J. 2002 Jan;95(1):14-6.
http://www.ncbi.nlm.nih.gov/pubmed/11928781?tool=bestpractice.com
Early symptoms and signs are the same as acute otitis externa (AOE), but, if left untreated, osteomyelitis of the petrous part of the temporal bone and/or skull base could result, which may invade soft tissue, the middle ear, inner ear, or brain.[1]Rosenfeld RM, Schwartz SR, Cannon CR, et al. American Academy of Otolaryngology-Head and Neck Surgery Foundation. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg. 2014 Feb;150(1 suppl):S1-24. [Erratum in: Otolaryngol Head Neck Surg. 2014 Mar;150(3):504].
https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599813517083
http://www.ncbi.nlm.nih.gov/pubmed/24491310?tool=bestpractice.com
[5]Walshe P, Cleary M, McConn WR, et al. Malignant otitis externa: a high index of suspicion is still needed for diagnosis. Irish Med J. 2002 Jan;95(1):14-6.
http://www.ncbi.nlm.nih.gov/pubmed/11928781?tool=bestpractice.com
[6]Johnson AK, Batra PS. Central skull base osteomyelitis: an emerging clinical entity. Laryngoscope. 2014 May;124(5):1083-7.
http://www.ncbi.nlm.nih.gov/pubmed/24115113?tool=bestpractice.com
The facial nerve may be affected, and less frequently, the glossopharyngeal and spinal accessory nerves.[1]Rosenfeld RM, Schwartz SR, Cannon CR, et al. American Academy of Otolaryngology-Head and Neck Surgery Foundation. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg. 2014 Feb;150(1 suppl):S1-24. [Erratum in: Otolaryngol Head Neck Surg. 2014 Mar;150(3):504].
https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599813517083
http://www.ncbi.nlm.nih.gov/pubmed/24491310?tool=bestpractice.com
Necrotizing otitis externa is a medical emergency.[7]Frost J, Samson AD. Standardised treatment protocol for necrotizing otitis externa: retrospective case series and systematic literature review. J Glob Antimicrob Resist. 2021 Sep;26:266-71.
https://www.sciencedirect.com/science/article/pii/S2213716521001661?via%3Dihub
http://www.ncbi.nlm.nih.gov/pubmed/34273591?tool=bestpractice.com
Pseudomonas aeruginosa is implicated in most patients.[1]Rosenfeld RM, Schwartz SR, Cannon CR, et al. American Academy of Otolaryngology-Head and Neck Surgery Foundation. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg. 2014 Feb;150(1 suppl):S1-24. [Erratum in: Otolaryngol Head Neck Surg. 2014 Mar;150(3):504].
https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599813517083
http://www.ncbi.nlm.nih.gov/pubmed/24491310?tool=bestpractice.com
[7]Frost J, Samson AD. Standardised treatment protocol for necrotizing otitis externa: retrospective case series and systematic literature review. J Glob Antimicrob Resist. 2021 Sep;26:266-71.
https://www.sciencedirect.com/science/article/pii/S2213716521001661?via%3Dihub
http://www.ncbi.nlm.nih.gov/pubmed/34273591?tool=bestpractice.com
Patients usually present with severe ear pain, otorrhea, and fullness, and are not responding to the conventional treatment of AOE. Depending on the stage of presentation and the extent of invasion, patients may have facial weakness and other cranial nerve abnormalities.[1]Rosenfeld RM, Schwartz SR, Cannon CR, et al. American Academy of Otolaryngology-Head and Neck Surgery Foundation. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg. 2014 Feb;150(1 suppl):S1-24. [Erratum in: Otolaryngol Head Neck Surg. 2014 Mar;150(3):504].
https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599813517083
http://www.ncbi.nlm.nih.gov/pubmed/24491310?tool=bestpractice.com
On physical exam, the external auditory canal is swollen, with evidence of granulation tissue on the floor of the canal and at the bony-cartilaginous junction.[1]Rosenfeld RM, Schwartz SR, Cannon CR, et al. American Academy of Otolaryngology-Head and Neck Surgery Foundation. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg. 2014 Feb;150(1 suppl):S1-24. [Erratum in: Otolaryngol Head Neck Surg. 2014 Mar;150(3):504].
https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599813517083
http://www.ncbi.nlm.nih.gov/pubmed/24491310?tool=bestpractice.com
The diagnosis is usually made by computed tomography or magnetic resonance imaging scans, which show presence of soft tissue and bone destruction.[5]Walshe P, Cleary M, McConn WR, et al. Malignant otitis externa: a high index of suspicion is still needed for diagnosis. Irish Med J. 2002 Jan;95(1):14-6.
http://www.ncbi.nlm.nih.gov/pubmed/11928781?tool=bestpractice.com
Otomycosis is a fungal infection of the external ear caused by molds and yeasts.[8]Kiakojuri K, Mahdavi Omran S, Roodgari S, et al. Molecular identification and antifungal susceptibility of yeasts and molds isolated from patients with otomycosis. Mycopathologia. 2021 May;186(2):245-57.
http://www.ncbi.nlm.nih.gov/pubmed/33718990?tool=bestpractice.com
Fungal otitis externa accounts for approximately 9% of total otitis externa.[8]Kiakojuri K, Mahdavi Omran S, Roodgari S, et al. Molecular identification and antifungal susceptibility of yeasts and molds isolated from patients with otomycosis. Mycopathologia. 2021 May;186(2):245-57.
http://www.ncbi.nlm.nih.gov/pubmed/33718990?tool=bestpractice.com
It presents in a similar way to acute bacterial otitis externa, with ear pain, itching, aural fullness, and otorrhea. It is common in tropical countries, humid locations, after long-term topical antibiotic therapy, and in people with diabetes, HIV/AIDS, or other immunocompromised states.[1]Rosenfeld RM, Schwartz SR, Cannon CR, et al. American Academy of Otolaryngology-Head and Neck Surgery Foundation. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg. 2014 Feb;150(1 suppl):S1-24. [Erratum in: Otolaryngol Head Neck Surg. 2014 Mar;150(3):504].
https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599813517083
http://www.ncbi.nlm.nih.gov/pubmed/24491310?tool=bestpractice.com
The most common fungal pathogens are Aspergillus species (60% to 90%) and Candida species (10% to 40%).[1]Rosenfeld RM, Schwartz SR, Cannon CR, et al. American Academy of Otolaryngology-Head and Neck Surgery Foundation. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg. 2014 Feb;150(1 suppl):S1-24. [Erratum in: Otolaryngol Head Neck Surg. 2014 Mar;150(3):504].
https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599813517083
http://www.ncbi.nlm.nih.gov/pubmed/24491310?tool=bestpractice.com
Stepwise multiplex polymerase chain reaction is more sensitive, rapid, and efficient than culture technique in differentiating bacterial otitis externa from fungal otitis externa.[9]Aboutalebian S, Ahmadikia K, Fakhim H, et al. Direct detection and identification of the most common bacteria and fungi causing otitis externa by a stepwise multiplex PCR. Front Cell Infect Microbiol. 2021;11:644060.
https://www.frontiersin.org/articles/10.3389/fcimb.2021.644060/full
http://www.ncbi.nlm.nih.gov/pubmed/33842390?tool=bestpractice.com
Tympanic membrane perforation may occur secondary to fungal otitis externa; a perforation rate of 6.75% has been reported.[8]Kiakojuri K, Mahdavi Omran S, Roodgari S, et al. Molecular identification and antifungal susceptibility of yeasts and molds isolated from patients with otomycosis. Mycopathologia. 2021 May;186(2):245-57.
http://www.ncbi.nlm.nih.gov/pubmed/33718990?tool=bestpractice.com
[10]Koltsidopoulos P, Skoulakis C. Otomycosis with tympanic membrane perforation: a review of the literature. Ear Nose Throat J. 2020 Sep;99(8):518-21.
https://journals.sagepub.com/doi/10.1177/0145561319851499?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed
http://www.ncbi.nlm.nih.gov/pubmed/31142158?tool=bestpractice.com
Perforation is common in otomycosis caused by Aspergillus flavus, Aspergillus tubingensis, and Candida albicans.[8]Kiakojuri K, Mahdavi Omran S, Roodgari S, et al. Molecular identification and antifungal susceptibility of yeasts and molds isolated from patients with otomycosis. Mycopathologia. 2021 May;186(2):245-57.
http://www.ncbi.nlm.nih.gov/pubmed/33718990?tool=bestpractice.com
The perforation of tympanic membrane due to fungal otitis externa is smaller in size and may resolve with treatment. Some cases may require tympanoplasty.[10]Koltsidopoulos P, Skoulakis C. Otomycosis with tympanic membrane perforation: a review of the literature. Ear Nose Throat J. 2020 Sep;99(8):518-21.
https://journals.sagepub.com/doi/10.1177/0145561319851499?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed
http://www.ncbi.nlm.nih.gov/pubmed/31142158?tool=bestpractice.com
Physical exam reveals swollen ear canal skin and discharge. Ear discharge may be thickened and black, gray, bluish green, yellow, or white.[1]Rosenfeld RM, Schwartz SR, Cannon CR, et al. American Academy of Otolaryngology-Head and Neck Surgery Foundation. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg. 2014 Feb;150(1 suppl):S1-24. [Erratum in: Otolaryngol Head Neck Surg. 2014 Mar;150(3):504].
https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599813517083
http://www.ncbi.nlm.nih.gov/pubmed/24491310?tool=bestpractice.com
The presence of black spores indicates Aspergillus niger as the causative organism.[1]Rosenfeld RM, Schwartz SR, Cannon CR, et al. American Academy of Otolaryngology-Head and Neck Surgery Foundation. Clinical practice guideline: acute otitis externa. Otolaryngol Head Neck Surg. 2014 Feb;150(1 suppl):S1-24. [Erratum in: Otolaryngol Head Neck Surg. 2014 Mar;150(3):504].
https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599813517083
http://www.ncbi.nlm.nih.gov/pubmed/24491310?tool=bestpractice.com
[3]Hirsch BE. Infections of the external ear. Am J Otolaryngol. 1992 May-Jun;13(3):145-55.
http://www.ncbi.nlm.nih.gov/pubmed/1626615?tool=bestpractice.com
White filamentous hyphae can often be seen. Microscopic exam and ear cultures can help establish the definitive diagnosis of otomycosis. Otomycosis should be suspected in patients who fail treatment with antibacterial agents.[3]Hirsch BE. Infections of the external ear. Am J Otolaryngol. 1992 May-Jun;13(3):145-55.
http://www.ncbi.nlm.nih.gov/pubmed/1626615?tool=bestpractice.com
Secondary fungal infection of the external auditory canal is well known after prolonged treatment with topical antibacterial agents.[11]Alshahni MM, Alshahni RZ, Fujisaki R, et al. A case of topical ofloxacin-induced otomycosis and literature review. Mycopathologia. 2021 Dec;186(6):871-6.
http://www.ncbi.nlm.nih.gov/pubmed/34410567?tool=bestpractice.com
Chronic otitis externa is chronic inflammation of the ear canal skin for 3 months or longer.[12]Jackson EA, Geer K. Acute otitis externa: rapid evidence review. Am Fam Physician. 2023 Feb;107(2):145-51.
http://www.ncbi.nlm.nih.gov/pubmed/36791445?tool=bestpractice.com
It usually presents with diffuse low-grade infection of months' or, at times, years' duration.[13]Selesnick SH. Otitis externa: management of the recalcitrant case. Am J Otology. 1994 May;15(3):408-12.
http://www.ncbi.nlm.nih.gov/pubmed/8579150?tool=bestpractice.com
It is the result of recurrent otitis externa, bacterial or fungal infections, underlying skin conditions, or otorrhea from middle ear infections.[3]Hirsch BE. Infections of the external ear. Am J Otolaryngol. 1992 May-Jun;13(3):145-55.
http://www.ncbi.nlm.nih.gov/pubmed/1626615?tool=bestpractice.com
Patients usually present with itching and scant otorrhea but no pain.[13]Selesnick SH. Otitis externa: management of the recalcitrant case. Am J Otology. 1994 May;15(3):408-12.
http://www.ncbi.nlm.nih.gov/pubmed/8579150?tool=bestpractice.com