Local inflammatory reactions leading to breakdown of skin where aciclovir has been infused into extravasated tissue. When administered intravenously as aciclovir sodium it may cause local reactions at the injection site with inflammation and phlebitis; these reactions may be associated with extravasation that leads rarely to ulceration.
Phototoxicity which in severe cases can cause erythematous swelling after brief exposure to the sun. Asymptomatic blue-grey discoloration on exposed areas