My five year old daughter...?

She my be allergic to something you are not aware of I would monitor what she eats and the clothes she wears to try to find a pattern of thing that occur before the rash appears. Also make sure you monitor what laundry detergent you use if you switch often it could be an allergy to one brand that you use. My sister has to use name brand detergent because her husband has sensitive skin and will get rashes if she tries to save money by using a generic brand.