Fungal necrotizing otitis externa; challenges in diagnosis and therapy

Necrotizing otitis externa (NOE) is a severe infection with potential skull base involvement. The role of fungal pathogens and the need for antifungal treatment remain controversial. We aimed to evaluate clinical characteristics, diagnostic challenges, and microbiology results in fungal NOE and assess considerations for antifungal therapy.

This retrospective cohort study was conducted at two tertiary centers. NOE patients, based on clinical and radiological findings, were retrospectively reviewed. Clinical characteristics, microbiological findings, and disease persistence were compared between patients categorized by antifungal treatment status: Combined antifungal-antibiotic therapy versus antibiotic therapy alone.

Of 125 patients, 25 received combined treatment (13 as initial treatment and 12 after persistent disease) and 100 received antibiotics alone. Combined treatment patients were younger, had prolonged symptoms, and more cranial nerve palsy, requiring longer treatment for persistent and aggressive disease. Fungi were found in 72% of combined-treatment cultures, but most were deemed unreliable by infectious diseases specialists, inconsistently leading to antifungal therapy.

Antifungal therapy decisions in NOE lack standardization. We propose a protocol incorporating clinical and microbiological data to guide antifungal therapy. Prospective studies are needed to validate this protocol and establish standardized guidelines for fungal NOE treatment.