M.K.
there is really not a great treatment for this...
My daughter has this and we do use a steroid cream to help a little is called mymyx. Try just using dove soap, aveeno, california baby. Thats what I use for my daughter. also use detergent ALL free and no fabric softeners. we have gone to a derm. and this is what I was told. Also, it has helped my daughter to take showers instead of bath so she is not soaking so much which can trigger it more.