I have polycythemia and experienced extreme itching for years, especially around my ankles. I mauled my poor ankles to death, especially at night. Triggers: warm/hot showers, exercise, hot (or even just warm) weather. But the itching happens even without those triggers. Nights are absolutely the worst.

Eventually, I broke the itch/scratch cycle:
1. I rid myself of any and all skin care products except Aveeno's special body wash and cream for dry itchy skin. No, my skin is not dry, it's just that I have found these products work for me like no other. I even use the body wash as simple hand soap. So, no acne washes, etc. No product hits my skin other than the above Aveeno products.
2. I lather myself up with the above body wash PRIOR to getting into the shower. Then, I turn the shower on and quickly rinse myself off in just-warm water. I do not linger in the shower or use hot water.
3. Whenever I start to itch, I rub the Aveeno cream into the itchy area.
4. Hypo-allergenic laundry detergent.

After a week or so, the itch/scratch cycle broke. My problem is now all but alleviated. But I am careful to NEVER scratch, knowing that I could start the cycle all over again.