Exanthem

An exanthem is a widespread rash, usually of viral origin, and usually occurring in children. It represents either a reaction to a toxin produced by the organism, damage to the skin by the organism or an immune response. Exanthems may also be due to a drug, most commonly antibiotics.

Historically, five "classical" childhood exanthems have been recognized: they are rubeola (measles), varicella (chicken pox), rubella, scarlet fever and "fifth disease". Roseola (aka exanthem subitum or "sixth disease") was later added to these. Vaccinations now exist against measles, rubella and chickenpox; scarlet fever is a streptococcal disease easily treated with antibiotics and the remaining two viral syndromes are considered benign.

A "new" exanthem was identified in 1992, unilateral laterothoracic exanthem (ULE), later also known as asymmetric periflexural exanthem of childhood.