Describe otomycosis with its management.

Nature and Presentation

• Otomycosis is fungal infection of the external auditory canal.
• It is particularly common in India because of the hot, humid climate, and accounts for a substantial proportion of all otitis externa here — far more than in temperate countries.
• Organisms — aspergillus is much the commonest, particularly A. Niger, then A. Fumigatus and A. Flavus; and candida albicans

Management

• Mechanical clearance IS the most important step and is regularly under-done. The fungal mass must be completely removed by suction and dry mopping under the microscope.
• Repeated toilet at intervals of a few days is required, and the commonest reason for treatment failure is inadequate or single cleaning
• Stop all antibiotic and steroid drops, which are perpetuating the infection; this is frequently the single most useful intervention
• Topical antifungals — clotrimazole 1% solution is the standard and is effective against both aspergillus and candida; also nystatin (for candida), miconazole and ketoconazole. Continue for at least 1 to 2 weeks after apparent clearance, since relapse is common
• Acidifying and drying agents — 2% acetic acid, boric acid in spirit and aluminium acetate, which restore the acid pH and dry the canal; these are cheap and effective and are widely used in India
• Systemic antifungals are rarely needed, and are reserved for invasive disease, the immunosuppressed, or where there is a perforation with middle ear involvement — itraconazole or voriconazole
• Keep the ear dry, which is essential to preventing recurrence, and treat any diabetes
• Take particular care where the drum is perforated or absent — many topical preparations are ototoxic, so alcohol-based and boric acid preparations must be avoided and only agents safe for the middle ear used
• Recurrence is common, and the patient should be told so and warned against self-medication with antibiotic drops
• Complications are rare but include tympanic membrane perforation, and, in the immunosuppressed, invasive aspergillosis extending to bone — which behaves like malignant otitis externa and carries a poor prognosis
• Itching predominates in fungal disease and pain in bacterial disease.
• Wet blotting paper sprinkled with pepper describes Aspergillus niger, and is close to diagnostic on sight
• Prolonged antibiotic and steroid drops cause it, which makes it the commonest iatrogenic ear infection