Suggest Treatment For Itching On Whole Body

hi, i have hot blood, i get terrible itch in my body whereever i cover my body with warm clothes i get itch before i was thinking its my skin but i am sure its my blood,coz my whole body is always quiet warm in actual fact my body is hot i ve been to many doctors they all say my blood test come as normal , i am really stuck with this prob, plz help me