Abstract
Introduction: :
Herpes simplex viral keratitis (HSK) is frequently a presumptive diagnosis as most patients do not present with dendritic keratitis or positive viral culture. The Herpetic Eye Disease Study (HEDS) recommends long term oral antivirals to prevent herpetic recurrences that can lead to vision loss. Multiple publications have confirmed the benefit of oral antivirals in post–herpetic corneal grafts.
Purpose: :
To determine whether presumed herpetic keratitis patients eligible for long term oral antiviral treatment have evidence of prior infection.
Methods: :
Retrospective chart analysis of 29 patients with presumed herpes simplex keratitis. 19 cases of non–surgical herpes keratitis were suitable for oral antivirals (acyclovir, famciclovir, valacyclovir) according to HEDS recommendations. 10 patients had penetrating keratoplasty (PK) for presumed HSV–related scarring and were on oral antivirals. Strong evidence of HSK was identified by the presence of a dendrite, positive herpes culture or positive HSV antigen in the corneal button by immunopathology. HSV Type 1 and Type 2 IgG serum titres, considered possible evidence, were drawn in all patients. Negative serum titres were used as a criterion to discontinue oral antivirals in patients who had no other evidence of herpes.
Results: :
We report data on 29 patients, 16 male and 13 female ranging from 25 to 84 years of age. The overall rate of HSV serum titre positivity was 89.7%. All patients who had a dendrite (6) or positive HSV eye culture (4) were HSV–1 serum positive. Among the 19 non–surgical presumed herpetic keratitis patients, 15 patients were HSV–1 seropositive and 2 were HSV–2 seropositive. 2 patients with non–surgical presumed herpetic keratitis had no evidence of HSV by culture or serum titre and antivirals were discontinued. Regarding patients with post–herpetic PK, 4 of the 10 patients had positive HSV–1 antigen in their corneal buttons using immunohistochemistry. 2 additional PK patients had positive HSV eye cultures. 9 of the 10 PK patients were HSV–1 seropositive. The one patient with negative HSV serology had positive immunostaining for HSV–1 of the button but a negative HSV–1 with PCR. Despite the discrepancy in the immunopathology, oral antivirals were discontinued.
Conclusions: :
3 of 29 (10.3%) patients with presumed HSK had no evidence of prior infection by HSV serum titre. In these patients, oral antiviral prophylaxis was discontinued without any recurrence thus far. Although oral antiviral prophylaxis is generally safe, long term therapy for herpetic keratitis may warrant at least serologic evidence of previous HSV exposure.
Keywords: herpes simplex virus • keratitis • cornea: clinical science