Limbal Subconjunctival Abscess: A Rare Complication of Acanthamoeba Keratitis

Acanthamoeba keratitis (AK) is a rare infection affecting the cornea. Immune-mediated sclerokeratitis is a well-documented late complication often requiring systemic immunosuppression. We present an alternative clinical presentation of subconjunctival abscesses caused by direct invasion of the Acanthamoeba and a proposed management strategy.

This study was a single case report performed at a tertiary care center in the United Kingdom.

A 42-year-old contact lens wearer with a history of swimming in contact lenses presented with 2 days of pain, redness, and photophobia. There was clinical suspicion for AK that was later confirmed on confocal microscopy and cultures. Four months into treatment with polyhexamethylene biguanide 0.06% monotherapy, they experienced a relapse of symptoms and developed multiple subconjunctival limbal abscesses with associated scleritis. These were drained in the office, and topical treatment changed to chlorhexidine 0.2%. The aspirate was culture-positive Acanthamoeba . Despite initially improving, the abscess reoccurred within a month. Repeat drainage was performed, and topical and oral voriconazole was added to the treatment regime. The abscess resolved leaving an area of scleromalacia.

Despite immune-mediated sclerokeratitis being a more common complication of AK, infectious scleritis can also occur. Correct identification of the cause of scleritis is required to prevent mistreatment of infectious scleritis with systemic immunosuppression. The abscess resolved with repeated drainage and the use of topical and systemic voriconazole.