Skin rashes

My children both have skin rashes and they are scratching I think it is because the weather has changed. I also have a lot of dry skin I put lotion on but after a few minutes I can feel my skin getting dry again. My husband said it may be because of the detergent that I use to wash with our clothes. He wants me to change our detergent to one that has no perfumes and cost more . I said that I would buy some tomorrow when I go to the store maybe he is right about it.