The breaking out or eruption of the skin. A rash is typically an area of the skin that is infected with red spots that can be filled with pus or with fluid.

Medically, a rash is referred to as an exanthem.

The word exanthem comes from the Greek exanthema which means "a breaking out".

Anthos in Greek is "a flower" particularly a flower blossom, so a child breaking out with a rash is sometimes compared to a flower that is blooming.