PURPOSE: To describe a case of severe dry eye syndrome in a child. METHODS: Observational case report. The authors de. scribe a 10,year old male with severe dry eyes who was profoundly disabled by pain and photophobia despite aggressive conventional therapy. Lacrimal gland histology was consistent with the primary Sjogren syndrome, and serologic and immunohistologic evidence supported the hypothesis of Epstein-Barr virus causality. RESULTS: Treatment with systemic acyclovir and cyclosporin A resulted in dramatic and rapid reversal of the profound sicca syndrome and enabled the patient to resume his normal activities. CONCLUSION: Epstein-Barr virus dacryoadenitis should be considered in the differential diagnosis of keratocon, junctivitis sicca in children. Epstein-Barr virus can cause keratoconjunctivitis sicca, which can be treated success fully with acyclovir therapy in addition to suppression of the inflammatory response. (C) 2001 by Elsevier Science Inc. All rights reserved.