[Valacyclovir Maintenance Therapy for a Case of Unilateral Acute Retinal Necrosis during Chemotherapy].

Acute retinal necrosis (ARN) is an infectious retinitis caused by varicella zoster virus (VZV), herpes simplex or cytomegalovirus. Without systemic therapy, ARN may progress bilaterally in seventy percent of unilateral patients. A 38-year-old-man was admitted to our hospital with Hodgkin's lymphoma and hemophagocytic lymphohistiocytosis. During the chemotherapy, left facial herpes zoster developed. He received valacyclovir for 14 days. After improvement of the blisters, he continued acyclovir as secondary prophylaxis. Three weeks after the facial zoster, sudden visual loss in the left eye occurred. ARN induced by VZV was diagnosed with ophthalmoscopy and the polymerase chain reaction test of the anterior chamber. Because continuous chemotherapy for Hodgkin's lymphoma was needed, he continued valacyclovir as secondary prophylaxis for 6 months and he accomplished the chemotherapy without contralateral progression. Our case suggested the utility of valacyclovir for secondary prophylaxis. Further experiments would be required to establish secondary prophylaxis in immunocompromised patients.