Tintelnotia Destructans Fungal Keratitis In A Patient With Behçet's Disease: A Case Report

To present a rare case of fungal keratitis in an immunosuppressed individual. Despite initial empirical management, molecular diagnostics identified Tintelnotia destructans, a rare and recently described filamentous fungus, requiring aggressive antifungal therapy.

A 41-year-old male presented to the emergency department with a one-day history of pain and redness in the left eye. His past medical history was significant for Behçet’s disease (HLAB51+), with recurrent oral ulcers, arthropathy, and prior ipsilateral posterior uveitis, for which he was receiving adalimumab and azathioprine. He was a regular user of soft contact lenses. On examination, conjunctival hyperemia and a paracentral corneal foreign body were noted, which was removed.

Single-center university hospital.

After ten days, symptoms persisted, with a decline in best-corrected visual acuity (BCVA) to 20/50 and increased pain. A small paracentral infiltrate was identified, prompting the initiation of dexamethasone 1 mg/mL three times daily, moxifloxacin 5 mg/mL six times daily, and cycloplegics as empirical therapy for presumed bacterial keratitis. After three days of intensive antibacterial treatment, there was no improvement, and an overlying epithelial defect was observed. Dexamethasone was discontinued, and antimicrobial therapy was intensified with alternating hourly administration of moxifloxacin and tobramycin 3 mg/mL.

Given the prolonged disease course and lack of therapeutic response, fungal keratitis was suspected, and clotrimazole 10 mg/mL six times daily was introduced. One week later, the patient exhibited a 2×2 mm paracentral corneal ulcer with an overlying epithelial defect and an adjacent ring infiltrate. Corneal scraping samples were obtained for microscopy, culture, and molecular analysis. Antifungal therapy was escalated to hourly voriconazole 2%, while chlorhexidine 0.02% and propamidine 0.1% were added six times daily.

One month later, microbiological analysis confirmed the presence of a filamentous fungus, identified as Tintelnotia destructans through Sanger sequencing. Systemic terbinafine (250 mg daily) and topical terbinafine 0.25% five times daily were initiated. Doxycycline 100 mg daily was prescribed as a matrix metalloproteinase inhibitor adjunct. 

Within two weeks of initiating terbinafine therapy, the patient exhibited substantial clinical improvement, including pain resolution, photophobia relief, increasing BCVA to 20/32, and resolution of the corneal infiltrate.

Tintelnotia destructans is an extremely rare and emerging cause of fungal keratitis, for which molecular diagnostic techniques were crucial in identifying the pathogen and allowing for a targeted therapy. With very few reported cases, the successful, off-label use of terbinafine presents a promising treatment option with a favourable safety profile, meriting further investigation.