I have psoriasis, an immune disorder disease that can make life miserable, with intensively itchy outbreaks of dry, cracking skin usually on the elbows, ankles, hands, and scalp. It goes into remission and usually is helped by exposure to sunlight. It is treated medically with steroid creams and drugs, but I refuse to take these as they are not cures and can cause long-term problems.
In the bath, you can try putting oatmeal in a cheesecloth bag and soaking. Also you can try soaking in salt water. After, put a neutral lubricant cream such as coconut oil or vaseline on the dry areas. Some skin problems are related to diet. In psoriasis, I keep away from excess meat and fat, sugar, including alcohol, and wheat. Also try taking vitamin supplements. You can monitor when the itching becomes worse, and try to find out if you have eaten or drank something which triggered it. Good luck!