SHORT COMMUNICATION

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Clinical Spectrum and Mycological Correlation in Otomycosis: An Observational Study.

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Abstract

Background: Otomycosis is a superficial fungal infection of the external auditory canal commonly seen in tropical and humid regions. Due to its nonspecific presentation and overlap with bacterial otitis externa, it is often underdiagnosed and inadequately treated.

Objective: To analyse the clinical presentation, mycological profile, and treatment outcomes of otomycosis in a tertiary care centre.

Methods: This prospective observational study included 20 patients with suspected otomycosis. After aural toileting and debris clearance, specimens from the external auditory canal were subjected to potassium hydroxide (KOH) mount and fungal culture on Sabouraud Dextrose Agar. Patients received empirical topical and systemic antifungal therapy, modified according to culture reports when necessary. Clinical outcomes were assessed after one week.

Results: Of the 20 patients, 14 (70%) were females and 6 (30%) were males, with a mean age of 31.8 years. Right ear involvement was seen in 10 patients (50%), left ear in 9 (45%), and bilateral disease in 1 (5%). Otalgia was present in all patients, followed by irritation (75%) and aural blockage (55%). Aspergillus niger was the predominant isolate in 16 patients (80%), followed by Candida albicans in 3 (15%). Mixed growth of Aspergillus niger and Rhizopus species was identified in 1 patient (5%). Complete symptom resolution occurred in 15 patients (75%), partial improvement in 4 (20%), and persistent symptoms in 1 (5%).

Conclusion: Otomycosis is a significant cause of otitis externa in tropical regions, with Aspergillus niger as the predominant pathogen. Early clinical recognition supported by microbiological evaluation and adequate aural toileting with antifungal therapy results in favourable outcomes.

Keywords

Otomycosis; Aspergillus niger; Candida albicans; Otitis externa; Antifungal therapy; External auditory canal.

Introduction

Otomycosis is a superficial fungal infection involving the external auditory canal and occasionally the auricle and tympanic membrane. It is commonly encountered in tropical and subtropical regions where high humidity and warm climatic conditions favour fungal growth. The disease accounts for nearly 10% of cases of otitis externa and is frequently associated with symptoms such as otalgia, pruritus, irritation, ear blockage, and hearing impairment. Despite its high prevalence, otomycosis is often underdiagnosed due to its nonspecific clinical presentation and overlap with bacterial otitis externa.[1]

Several predisposing factors have been implicated in the development of otomycosis, including excessive ear cleaning, use of topical antibiotics, humid environmental conditions, hearing aid usage, trauma to the external auditory canal, and immunocompromised states.[2] Aspergillus and Candida species are the most commonly isolated fungi, with Aspergillus niger reported as the predominant organism in most Indian studies.[3,4]

The present study was undertaken to evaluate the clinical spectrum, microbiological profile, and treatment outcomes of otomycosis among patients attending a tertiary care centre and to compare the findings with existing literature.

Methods

Study Design and Setting

This prospective observational study was conducted in the Department of Otorhinolaryngology at a tertiary care centre after obtaining approval from the Institutional Ethics Committee (RRMCH-IEC/116/2019-20).

Study Population

20 consecutive patients presenting with symptoms suggestive of otomycosis were included in the study.

Inclusion Criteria

Patients presenting with one or more of the following symptoms were included:

Clinical Evaluation

All patients underwent detailed otoscopic and microscopic examination following meticulous aural toileting and removal of fungal debris. The condition of the EAC epithelium and tympanic membrane was documented. Figure 1A, 1B.

Figure 1A: External image of otomycosis showing fungal mass at the EAC.
Figure 1B: Debris extracted from the external auditory canal

Microbiological Evaluation

Specimens obtained from the EAC were subjected to:

Figure 2A–2C: Microscopic appearance of fungal elements isolated from otomycosis specimens demonstrating Aspergillus species morphology. Lactophenol Cotton Blue (LPCB) stain showing septate branching hyphae and characteristic conidial heads under high-power light microscopy (400× magnification)]

Fungal isolates were identified based on colony morphology and microscopic characteristics using lactophenol cotton blue staining.

Figure 3A–3B: Fungal culture on Sabouraud Dextrose Agar (SDA) demonstrating characteristic black, powdery to cottony colonies of Aspergillus niger following incubation under aerobic conditionsat 25–28°C for 5–7 days.

Treatment Protocol

Patients were initiated on topical Clotrimazole with Lignocaine ear drops along with systemic antifungal therapy using either Fluconazole 150 mg twice daily or Itraconazole 200 mg once daily for seven days. Routine analgesics and antibiotics were prescribed when clinically indicated.

Follow-up

Patients were reassessed after one week. Treatment modifications were made based on fungal culture findings and clinical response.

Variables Assessed

The following variables were analysed:

Statistical Analysis

Data were analysed using descriptive statistics and expressed as frequencies and percentages.

Results

A total of 20 patients diagnosed with otomycosis were included in the study. Females constituted the majority of the study population, accounting for 14 cases (70%), while males accounted for 6 cases (30%). The age of the patients ranged from 9 to 55 years, with a mean age of 31 years and 9 months.

The right ear was involved in 10 patients (50%), the left ear in 9 patients (45%), and bilateral disease was observed in 1 patient (5%).

Otalgia was the most common presenting symptom and was observed in all patients (100%). Irritation or pruritus was noted in 15 patients (75%), while aural blockage was present in 11 patients (55%). Giddiness and tinnitus were each reported by 1 patient (5%). [Table 1]

Table 1. Clinical Presentation of Patients with Otomycosis.

On otoscopic examination, fungal debris involving the entire EAC was observed in 9 patients (45%), while debris confined to the bony EAC was observed in 10 patients (50%). Isolated tympanic membrane involvement was noted in 1 patient (5%). Black-coloured debris was the most common appearance and was observed in 12 patients (60%), followed by yellow debris in 4 patients (20%), mixed-coloured debris in 3 patients (15%), and white debris in 1 patient (5%).

Congestion of the EAC epithelium was observed in 8 patients (40%), while ulceration was noted in 3 patients (15%). Tympanic membrane congestion was present in 7 patients (35%). Three patients (15%) demonstrated tympanic membrane ulceration, including one patient with associated bleeding. Tympanic membrane perforation was identified in 3 patients (15%), comprising one subtotal perforation and two small central perforations.

Clinical improvement following antifungal therapy was observed in the majority of patients. Complete symptom resolution was achieved in 15 patients (75%), partial improvement in 4 patients (20%), and persistent symptoms in 1 patient (5%). Recurrence could not be assessed because of the short follow-up duration.

Discussion

Otomycosis is a common fungal infection affecting the external auditory canal, particularly in tropical and humid climates. The condition is usually caused by Aspergillus and Candida species and is frequently associated with local trauma, excessive ear cleaning, and prolonged use of topical antibiotics.[1,2]

In the present study, females constituted 70% of the affected population. Similar female predominance has been reported in several Indian studies.[3,5] This may be attributed to increased use of cotton buds, cosmetic ear cleaning practices, hair oil application, and greater healthcare-seeking behaviour among females. However, the exact reason for female predominance remains uncertain and may vary between populations.

The mean age observed in this study was comparable to previous studies reporting otomycosis predominantly among young and middle-aged adults.[4,5] The right ear was slightly more commonly affected, although no significant laterality preference has been consistently reported in literature.

Otalgia was the most common symptom observed in the present study, followed by irritation and aural blockage. Similar symptom distribution has been reported by Pradhan et al. and Munguia and Daniel, who identified pain, pruritus, and hearing blockage as the predominant presenting complaints in otomycosis.[4,6]

Aspergillus niger was the predominant fungal isolate in the present study, accounting for 80% of cases. This finding is consistent with previous Indian and international studies reporting Aspergillus species as the most common etiological agent, with prevalence ranging from 60% to 85%.[3,4,6] The predominance of Aspergillus species may be related to the warm and humid environmental conditions favourable for fungal proliferation.

Candida albicans was isolated in 15% of patients, which is comparable to previous reports.[5] One patient demonstrated mixed fungal growth with Aspergillus niger and Rhizopus species, indicating the possibility of polymicrobial fungal colonisation in chronic cases.

Direct microscopy using KOH mount and fungal culture on SDA remain essential diagnostic tools for confirming fungal infection. Identification of fungal morphology assists in differentiating Aspergillus from Candida species and facilitates targeted therapy.[2] [Table 2]

Table 2. Mycological Profile of Otomycosis

Most patients in the present study demonstrated favourable clinical response following aural toileting and antifungal therapy. Complete symptom resolution was observed in 75% of patients after one week of treatment. Similar treatment outcomes have been reported in previous studies emphasizing the importance of meticulous debris clearance combined with topical antifungal therapy.[4,6]

Limitations

The present study has several limitations. The sample size was relatively small, and the study was conducted at a single tertiary care centre, limiting generalizability. The short duration of follow-up prevented assessment of long-term recurrence rates. Additionally, antifungal susceptibility testing was not performed, which could have provided valuable information regarding resistance patterns and guided targeted antifungal therapy.

Conclusion

Otomycosis remains a common fungal infection of the external auditory canal in tropical regions, predominantly caused by Aspergillus niger. Clinical diagnosis supported by microbiological evaluation facilitates accurate identification and targeted treatment. Early diagnosis, meticulous aural toileting, and appropriate antifungal therapy contribute to favourable clinical outcomes in the majority of patients.

Funding

None.

Ethical Approval

The study was approved by the Institutional Ethics Committee of RRMCH (RRMCH-IEC/116/2019-20). Informed consent was obtained from all participants.

Conflicts of Interest

None declared.

References