Extravasation of Intravenous Acyclovir in a Patient With Human Herpesvirus 7 Encephalitis: A Case Report

Acyclovir is a widely used antiviral agent, but intravenous administration can cause cutaneous adverse reactions, particularly extravasation. We report a rare case of acyclovir extravasation in a 20-year-old female patient with human herpesvirus 7 (HHV-7) encephalitis, who developed immediate vesicular skin lesions at the infusion site. The rapid improvement after drug withdrawal and cold compression favored extravasation over herpes infection progression or drug eruption. Acyclovir's high osmolality and alkalinity contribute to tissue damage. While no standard protocol exists, early detection, infusion discontinuation, aspiration, saline infiltration, cold compression, and hyaluronidase can help minimize injury. This case highlights the importance of prompt recognition and management to prevent complications.