Most viruses that cause skin infections can be divided into several major groups. These include:

• Human herpesvirus (HHV). This family of viruses includes strands of the herpes simplex virus that cause cold sores (herpes simplex virus type 1) and genital lesions (herpes simplex virus type 2), and the herpes zoster virus that causes chickenpox and shingles. Human herpesviruses 6 and 7 cause a childhood illness called roseola infantum that can cause high fever and rash. Systemic antiviral agents are typically used to treat HHV.
  
  

  

• Human papillomavirus (HPV). A group of viruses that cause various types of warts (papillomas). These include common warts, foot warts, flat warts, genital warts and filiform warts. Some types of warts require no treatment, whereas others may need treatment with topical or systemic antiviral agents.
  
  
• Poxvirus. A group of viruses that include cowpox, monkeypox, and smallpox. One of the most destructive viral infections, smallpox has been eradicated throughout the world. Since 1978, only isolated, laboratory-acquired forms of the disease have been reported. It is usually treated with a vaccine that is effective up to four days after exposure, although the drug cidofovir has shown promise in the laboratory as a potential treatment.
  
  
• Human immunodeficiency virus (HIV). HIV is the virus that causes acquired immune deficiency syndrome (AIDS). Skin lesions that appear as a result of this infection are often the first sign that the patient has HIV. These lesions often result from a separate infection with HHV, papillomavirus or other infectious agents. Systemic antiviral agents are typically used to treat HIV. Numerous other medications are available that specifically treat HIV.