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.