You are diabetic and having chronic renal failure
as you said.
And there is intense itchy rash on most of the parts of the body.
I feel, the rash is related to your internal diseases.
Most probable cause is CRF.
Even diabetes can also lead to severe itching
Take hydroxyzine HCL 25 mg daily at night.
10 mg daily in morning.
Avoid steroids as the DM and CRF might worsen.
Apply mild steroid with crotorax cream on rash twice day.
Take proper treatment of DM and CRF from physician.
And for skin part, consult dermatologist
You may be improved.
I hope you got my answer.
Dr. Ilyas Patel MD