A rare case of pneumococcal keratitis in a patient with Herpes Zoster Ophthalmicus and compromised immune status

Infectious keratitis is commonly encountered in the ophthalmology emergency department. Streptococcus pneumoniae causing bacterial keratitis is a cause of concern in developing countries, owing to its complication of irreversible corneal scarring. This is a rare case report of a 25-year-old immunocompromised patient who presented to the Ophthalmology Department in a tertiary care hospital in India with complaints of diminution of vision in the left eye with pain, redness and watering, along with a history of vesicular painful rashes involving the left side of the forehead, the tip of the nose and the supraciliary area. Gram-positive lanceolate diplococci and plenty of pus cells were seen on the Gram staining of the corneal abscess scrape. The clinical presentation of the patient led to a provisional clinical diagnosis of secondary bacterial infection in Herpes Zoster Opthalmicus (HZO), corneal abscess with herpetic keratitis. Quellung reaction yielded an 18C serotype of the isolated pneumococci. Prompt treatment was required to prevent rapidly progressive complications.