Pyrenocheata unguis-hominis: A new cause of fungal keratitis in a contact lens wearer

PURPOSE: Pyrenochaeta unguis-hominis (syn. Neocucurbitaria unguis-hominis) is a rare fungal species belonging to the Coelomycetes group, mostly isolated from infected nails and skin. We present a case of contact lens-related fungal keratitis caused by Pyrenochaeta unguis-hominis. OBSERVATIONS: We present a case of a 69-year-old woman with multiple risk factors for a fungal keratitis including ophthalmological history of herpetic keratitis, contact lens wear and chronic steroid use. At presentation, the corneal ulcer resembled a recurrent herpetic keratitis but evolved into a more dense stromal infiltrate despite antiviral therapy. Microscopic examination, culture and staining of corneal tissue obtained by scraping showed mycelia. PCR and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry confirmed the presence of Pyrenochaeta unguis-hominis. Topical antifungal treatment was able to dim the inflammation. Because of a persistent epithelial defect, an amniotic membrane transplantation was performed. Although corneal epithelium was restored, stromal scarring in the visual axis resulted in substantial vision loss. CONCLUSIONS: To our knowledge no other cases of fungal keratitis caused by Pyrenochaeta unguis-hominis have been described. Early diagnosis can allow prompt initiation of antifungal treatment, which should be guided by in vitro susceptibility testing.