Joslin Diabetes Center says this:
“People with diabetes are prone to dry skin, particularly when blood glucose levels run high. This causes the body to lose fluids and skin to become dry. Dry skin can crack and itch, which can lead to infections. You may also get dry skin with diabetes if you have neuropathy. The nerves in the legs and feet may not get the message to sweat, which is necessary to keep skin soft and moist. Keeping your skin moisturized when you have diabetes is one of the easiest ways to prevent skin problems.”
https://www.joslin.org/info/good_skin_care_and_diabetes.html