otomycosis

Otomycosis

Otomycosis refers to a fungal ear infection (mold or yeast infections) of the outer ear canal 1). Species that cause fungal infections in the ear include saprophytic filamentous fungi, yeast and dermatophytes 2). Aspergillus species and Candida albicans are the most frequently isolated fungi in patients with otomycosis 3). Aspergillus species infection represent almost 95% of the mold isolates. Aspergillus niger is the most frequent species, followed by Aspergillus fumigatus and Aspergillus flavus. The infections are not contagious. It is more common in tropical countries. The clinical presentation may vary with chronic, acute or sub-acute inflammation of the ear which rarely involves the middle ear or chronic invasive forms described 4). The course is chronic with acute episodes, especially in summer, and intermittent remissions. Aspergillus species may invade the external auditory canal of immunocompromised patients, extending into contiguous bone or even the brain.

Otomycosis is usually a secondary infection, which can be related to various risk factors such as swimming, hot weather, the absence of cerumen, working in a dry and dusty environment, use of hearing aids, poor health status, genetic factors and ear surgery 5). Patients commonly present with impaired decreased hearing, itching (pruritus), tingling, ear pain (otalgia) or ear discharge (otorrhea).

Otomycosis is prevalent among adults, while other age groups such as children may also be affected. Otomycosis has a higher prevalence in the 21–30-year age group, and lower among individuals 10 years or younger and over 60 years of age 6). Otomycosis is usually unilateral infection and interestingly, some articles have reported a higher prevalence of the disease among women 7), while others have reported a higher prevalence among men 8).

Clinical examination usually shows white, gray, and black or cheese-like tissues and inflammation on the outer ear 9). Otoscopy reveals greenish or black fuzzy growth on the cerumen or debris in the outer auditory canal. The diagnosis is reached by direct microscopy and culture. Histopathology is required in some cases.

Patients with noninvasive otomycosis should be treated with intense local debridement and cleansing in combination with topical antifungal agents and systemic antifungals and the discontinuation of local antimicrobials 10). Topical antifungals, such as clotrimazole, miconazole, bifonazole, ciclopiroxolamine, and tolnaftate, are potentially safe choices for the treatment of otomycosis, especially in patients with a perforated eardrum 11). Local clotrimazole is the most common antifungal used in such treatments 12). Some compounds with disinfection properties such as betadine and boric acid in combination with miconazole have also been used 13). The oral triazole drugs, itraconazole, voriconazole, and posaconazole are effective against Candida and Aspergillus, with good penetration of bone and the central nervous system. These drugs are essential in the treatment of patients with malignant fungal otitis externa complicated by mastoiditis and meningitis.

The prognosis in immunocompetent patients is good, but immunocompromised patients can develop acute invasive or chronic invasive forms that can be life threatening.

The rate of recurrence of otomycosis in a report published by Jia et al. 14) in China was 8.98% among 108 patients, and it was reported that recurrence was not uncommon, and that it is difficult to eradicate the infection in patients with diabetes and mastoid cavity. In another study 15) conducted in Nigeria in 5,784 patients with ear diseases, 378 cases (54.6%) had otomycosis, among whom the recurrence rate was reported for 17 patients after 6 months of treatment (4.50%).

Otomycosis causes

Otomycosis refers to a fungal ear infection (mold or yeast infections) of the outer ear canal 16). Species that cause fungal infections in the ear include saprophytic filamentous fungi, yeast and dermatophytes 17). Aspergillus species and Candida albicans are the most frequently isolated fungi in patients with otomycosis 18). Aspergillus species infection represent almost 95% of the mold isolates. Aspergillus niger is the most frequent species, followed by Aspergillus fumigatus and Aspergillus flavus. The infections are not contagious. It is more common in tropical countries.

Otomycosis is usually a secondary infection, which can be related to various risk factors such as manipulating the ears, humid climate, swimming, use of hearing aids, presence of cerumen, instrumentation of the ear, increased use of topical antibiotic/steroid preparations, hot weather, working in a dry and dusty environment, age, genetic factors, ear surgery, predisposing primary bacterial infection, poor health status, and immune system disorders 19).  such as   the absence of cerumen,    20).

Otomycosis symptoms

Patients commonly present with impaired decreased hearing, itching (pruritus), tingling, ear pain (otalgia) or ear discharge (otorrhea).

The key physical finding of otomycosis is pain upon palpation of the tragus (anterior to ear canal) or application of traction to the pinna. Patients may also have the following signs and symptoms:

  • Otalgia – Ranges from mild to severe, typically progressing over 1-2 days
  • Hearing loss
  • Ear fullness or pressure
  • Erythema, edema, and narrowing of the external auditory canal
  • Tinnitus
  • Fever (occasionally)
  • Itching (especially in fungal otitis externa or chronic otitis externa)
  • Severe deep pain – Immunocompromised patients may have necrotizing (malignant) otitis externa
  • Discharge – Initially, clear; quickly becomes purulent and foul-smelling
  • Cellulitis of the face or neck or lymphadenopathy of the ipsilateral neck (occasionally)
  • Bilateral symptoms (rare)
  • History of exposure to or activities in water (frequently) (eg, swimming, surfing, kayaking)
  • History of preceding ear trauma (usually) (eg, forceful ear cleaning, use of cotton swabs, or water in the ear canal)

Otomycosis diagnosis

The patient’s history and physical examination, including otoscopy, usually provide sufficient information for the clinician to make the diagnosis of otomycosis. Clinical examination usually shows white, gray, and black or cheese-like tissues and inflammation on the outer ear 21). Otoscopy reveals greenish or black fuzzy growth on the cerumen or debris in the outer auditory canal. The diagnosis is reached by direct microscopy and culture. Histopathology is required in some cases.

Note that a patient who is diabetic or immunocompromised with severe pain in the ear should have necrotizing otomycosis excluded by an otolaryngologist.

Laboratory testing

Typically, laboratory studies are not needed, but they may be helpful if the patient is immunocompromised, if the usual treatment measures are ineffective, or if a fungal cause is suspected. Tests may include the following:

  • Gram stain and culture of any discharge from the auditory canal
  • Blood glucose level
  • Urine dipstick

Imaging studies

Imaging studies are not required for most cases of otomycosis. However, radiologic investigation may be helpful if an invasive infection such as necrotizing (malignant) otomycosis is suspected or if the diagnosis of mastoiditis is being considered.

Imaging modalities may include the following:

  • High-resolution computed tomography (CT) – Preferred; better depicts bony erosion
  • Radionucleotide bone scanning
  • Gallium scanning
  • Magnetic resonance imaging (MRI) – Not used as often as the other modalities; may be considered secondarily or if soft-tissue extension is the predominant concern

Otomycosis treatment

Patients with noninvasive otomycosis should be treated with intense local debridement and cleansing in combination with topical antifungal agents and systemic antifungals and the discontinuation of local antimicrobials 22). Topical antifungals, such as clotrimazole, miconazole, bifonazole, ciclopiroxolamine, and tolnaftate, are potentially safe choices for the treatment of otomycosis, especially in patients with a perforated eardrum 23). Local clotrimazole is the most common antifungal used in such treatments 24). Some compounds with disinfection properties such as betadine and boric acid in combination with miconazole have also been used 25). The oral triazole drugs, itraconazole, voriconazole, and posaconazole are effective against Candida and Aspergillus, with good penetration of bone and the central nervous system. These drugs are essential in the treatment of patients with malignant fungal otitis externa complicated by mastoiditis and meningitis.

Dundar and İynen 26) conducted a prospective study on 40 patients with otomycosis. In this study, the ear canal was filled with 1% clotrimazole, using an intravenous catheter and syringe 27). The authors described the efficacy of single clotrimazole 1% was good for the treatment of otomycosis 28). Swain et al. 29) showed a study on 44 recalcitrant otomycosis patients who were divided into two groups. One group was treated with clotrimazole and the other group was treated with povidone iodine. The povidone iodine treatment at recalcitrant otomycosis patients was effective and well tolerated 30). Omran et al. 31) showed that the use of combination treatment with ceftizoxime and clotrimazole drugs was useful in treatment of the otomycosis patients with tympanic membrane rupture. In Kiakojori et al.’s study 32), 2% miconazole ointment was an effective treatment in cases with otomycosis. The results of this study 33) showed that clotrimazole can have a preventive role in the relapse of otomycosis. Major cases of relapse were observed in those who had inflamed or ulcerated canal and tympanum. Based on the obtained result, it is suggested that in those with otomycosis, especially in individuals with disorders in their ears and tympanum, clotrimazole drop can be used to prevent the relapse of otomycosis.

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