Hello,
It can be due to atopic dermatitis or eczema. The typical treatment of eczema includes topical steroids and plenty of moisturizers.
There are certain other non-pharmacological measures which are equally important in treating atopic dermatitis. These are lubricating the skin frequently, avoiding harsh soaps and cleansers, preventing scratching or rubbing whenever possible, protecting skin from excessive moisture, irritants, and rough clothing, maintaining a cool, stable temperature and consistent humidity levels, limiting exposure to dust, pollens, and animal dander.
I hope it helps. Take care and regards.
This is known as 'Atopic dermatitis'. Keep the skin moist with Vaseline. Continue hydrocortisone for short periods. Your son will out grow these soon.