|Origin:||Early French rache 'small pieces of loose skin', from Latin radere; RAZE|
a lot of red spots on someone's skin, caused by an illness:
She had a nasty rash on her arm.
come/break out in a rash (=get a rash)
My mother comes out in a rash if she eats seafood.
Most babies get nappy rash at some stage.
a heat rash (=a rash caused by heat)
a large number of unpleasant events, changes etc within a short time [= spate of something]:
There's been a rash of car thefts in the city centre.