Keratomycosis caused by Exserohilum rostratum

Area of Science:

• Ophthalmology
• Mycology
• Infectious Diseases

Background:

• Keratomycosis, or fungal keratitis, is a serious ocular infection.
• Trauma with vegetative matter is a known risk factor for fungal eye infections.
• Exserohilum rostratum is a dematiaceous fungus increasingly recognized as a cause of human infections.

Observation:

• A 46-year-old farmer presented with a 2-week history of right eye pain, discharge, and redness post-trauma.
• Ocular examination revealed a central corneal ulcer with characteristic feathery edges and diffuse edema.
• KOH microscopy of corneal scrapings showed thick, brown, septate hyphae consistent with fungal elements.

Findings:

• Culture of corneal scrapings identified Exserohilum rostratum based on velvety, greenish-black colonies with black reverse pigment.
• Microscopic morphology confirmed the presence of branched, septate hyphae.
• The patient demonstrated a positive clinical response to topical natamycin and oral itraconazole.

Implications:

• This case underscores Exserohilum rostratum as a potential pathogen in fungal keratitis, particularly following agricultural trauma.
• Prompt diagnosis through direct microscopy and culture is crucial for effective management.
• Combination therapy with topical and oral antifungals can successfully treat Exserohilum rostratum-induced keratomycosis.