Suggest Treatment For Itching Rashes On Arms, Hands And Feet

My daughter has a rash on her feet, arms, and hands that is red like a sunburn and she says it itches. She thinks she has a heat rash due to the rash appears more prevelant when she comes inside after being out in the heat. The rash on her arms and legs do become a lighter shade of pink as she settles down from coming inside. However, her feet are bright red, they feel warm, and the color has not faded from a bright red in three days. What could this be? She has not been sick or had any fever.