You didn't give us much information to work with. Uncontrolled and unmanaged diabetes are one of several causes for itchy skin. So are fungal infections, dry skin, and kidney issues.
In order to assist you better it is always important to include in your post -
1. What you are doing to control and manage your diabetes
2. When you test your glucose and respective test results
3. If you have visible rash/sore/redness
3. If you apply recommended moisturizing cream to affected areas
4. If you traveled to another country
5. Results of an physicians medical evaluation
And the list goes on.....
If you haven't seen a Dermatologist, I suggest you do to rule out skin issues. If your diabetes is uncontrolled and unmanaged a visit to an Endocrinologist is in order to reevaluate your lifestyle and diabetes medication/s. Good luck