My 3yo LO tends to scratch herself before she sleeps. She seems to itch though I really do not know what she's allergic to. She does have mild ezcema when she was a baby. Do your kids do that too?

Not sure if it's the same, but my friend changed her detergent to one that is for sensitive skin (she changed to Seventh Generation) and changes the sheets regularly (to minimize exposure to dust mites). She also applies Aveeno Baby Eczema cream after bath and before her baby sleeps to help ease the itch.