Itchy skin without any rash can be due to xerosis or dry skin which can happen because of hot or cold weather with low humidity levels, long-term use of air conditioning or central heating, and washing or bathing too much.
Other causes include internal diseases like liver and kidney disorders, diabetes, iron deficiency anemia, irritation and allergic reactions to chemicals, wool, soaps, cosmetics and certain foods .
You can apply an anti-itch cream or lotion to the affected area. Oral antihistamine, such as Benadryl can also be used. You should take a comfortably cool bath and wear smooth-textured cotton clothing. Also choose mild soaps without dyes or perfumes and use a mild, unscented laundry detergent when washing clothes, towels and bedding. If the symptoms persist then please get evaluated for diabetes, thyroid diseases and iron deficiency anemia. I hope it helps. Take care and God bless.