Can Itchy, Dry Skin With Rashes During Summer Be Treated?

hi, my daughter is 8 yrs now. She has been suferring from skin allergy since last yr. During winter season she is ok, but in summer season she is suferring from skin allergy again. Red rashes in different locations on her body is appeared suddenly and itching also. Then she is getting restless. At that time she has to take phenargan syrup which is prescribed by child specialist. After some time rash and itching both are hidden. Please help me.