Childhood exanthems. Old and new.

Exanthems are a common cause of rashes in children. Several recent developments have sparked a renewed interest in this group of diseases, including the identification of parvovirus B19 and human herpesvirus 6 as the causative agents of erythema infectiosum and roseola infantum. The resurgence of measles as a childhood exanthem has caused a re-examination of current immunization practices. The most common and clinically significant exanthems are discussed, with an emphasis on new findings, origins, clinical manifestations, differential diagnosis, and management.