i have always used destinin (sp?) cream for nappy rash with seems to do the job i put heaps on and then put some curash powder over the top.

just a little tip to (although you might already do it) but i know on the occassions my kiddies have had nappy rash it hurts like almighty when you put them in the bath, so when they have bad nappy rash before bathing them i smother their bottom in vaseline and it gives it a sort of barrier and that initial sting when entering the water isn't as bad.

good luck