feet afection

Question
Two weeks ago my rabbit started losing fur on his heels. (without ulceration).  
The vet prescribed a cream which commercial name is Quadriderm and his opinion was that this was caused by some humid surface where the rabbit stayed. (perhaps while I was cleaning)
He lives in the living room (no cage) and he has a litter box covered with newspaper which is changed daily.  
Evolution is to slow: After 2 weeks of treatment, very few fur was recovered on the heels but the lost of fur extended to the upper part of the feet.
I'm afraid this was caused by something else or may be treatment is not suitable.
What's your opinion?
Thanks a lot
Maria  

Answer
hi maria -firstly you have not told me what type of rabbit it is.
my breed is rex rabbits and these are very prone to bare heels -to keep them ok i run them on thick sawdust so they have something soft underfoot , and this works .
having it indoors is probably the main reason as the floors are hard, and as i have said the rabbit needs somthing very soft to run on.
dave.