Viral exanthems in childhood. Part 3: Parainfectious exanthems and those associated with virus-drug interactions.

Viruses cause not only direct infectious exanthems, but also parainfectious exanthems, which provoke skin alterations via interactions with the immune system. These distinct exanthems, for instance Gianotti-Crosti syndrome and pityriasis lichenoides group, do not reflect a specific pathogen but can occur in the course of many viral infections. In addition, some exanthems result from the interaction between viruses and drugs.