How do I treat a child's broken damp skin from nightnappies?

My 4 year old still wears night nappies and is wet more often that not in the morning. She often has awful itchy cracked skin and the skin looks a pale pink/whitish. It looks to me that the wet pants are causing the skin to turn soft and saturated and cracked. or is it something else eg candida? what should i giver her? She is at nursery all day so I can't let her walk round with no pants on to dry out there...