that isn't accompanied by other obvious skin
changes, such as a rash, is most often caused by dry skin (xerosis). Skin conditions like dermatitis, lice, scabies and hives, internal diseases like liver and kidney disorders, diabetes, iron deficiency anemia, irritation and allergic reactions to chemicals, wool, soaps, cosmetics and certain foods can cause itchy skin.
It can be due to liver causes also. Get your liver function tests done and consult a dermatologist.