My two-year-old son has had this rash five times in the last eight months it starts off as a skin coloured rash and progresses to be red and then purple which do not blanch when pressed. However the whole rash disappears within a week. He does not appear to be ill otherwise. The GP has no idea what it is. This time the rash is in it's usual place on his forehead although he has a few on his arm and a few under his chin and on his scalp.