My 2 older children had them when they were 1 1/2 (cah daughter) and 3 (non-cah).  The worst part was having the pox inside the diaper area.  I remember it being very uncomfortable for her even though it was 12 years ago.  She ran a low grade fever for about 2 days and that was it.  We did not have newborn screening for CAH back then, so we were unaware that she even had cah until she was 5.  In that sense, our daughter went through a number of major illnesses without cah medication and luckily survived.  She is obviously not a salt-waster, but does have classic sv cah.