Antiviral agents are medications designed to combat viral infections. A virus is a tiny infectious organism that invades cells and forces them to replicate the virus. These new viruses then go out and attack other cells, including skin cells. Antivirals can be used to treat existing infections or to prevent a person from becoming infected with a virus.

Most viruses that cause skin infections can be divided into several major groups, including human herpesvirus (HHV), which includes herpes simplex virus (HSV) and herpes zoster virus; human immunodeficiency virus (HIV) and human papillomavirus (HPV). These viruses cause disorders such as warts, cold sores, chicken pox and shingles. The HIV virus can lead to AIDS.