Hi..Thanks for the query.
The patches ,if are 'sore' might indicate an ongoing inflammation.From the site you mention , eczema
might be an important thing to consider.Over a period of time , due to scratching and inflammation , these areas tend to become thick ,when we call them Lichen Simplex Chronicus
You can apply medicated emollients several time of the day to keep the area very very hydrated.Do not use synthetic socks and choose your footwear wisely.Any friction should be minimized in this area.
A topical steroid
with salicylic acid
can be used for 2-3 weeks to reduce the activity .
I would advise you to see a dermatologist
for the same.
Hope this helps.