You may want to try PREVENTION, too.
I'm past my diapering years (thank God!), but I keep reading about how washing diapers with Soap Nuts reduces or eliminates many baby skin irritations. I started using them for my skin is very sensitive to store bought detergents. I've also replaced numerous other cleaners in the house. My chemical sensitivities has grown to be awful in recent years. I can only imagine how susceptible an infant's tender skin must be.
Frankly, I'm using Soap Nut based soap bars, shampoos, and cleaners - plus Olive Oil based washes, lotions and cremes. NO MORE PROBLEMS!
My preferred cleaner/detergent is NaturOli's Extreme 18X, which is a concentrated liquid made from organic Soap Nuts. It's VERY convenient to use. A little squirt or two goes a long way! Some links:
http://www.naturoli.com/soapnuts/
https://store.naturoli.com/
http://www.soapnuts.pro/
Amazon offers many of these products, too. Just search for "soap nuts".
Good luck!