What could be causing my cat to loss patches of hair on his legs

Question
I have a white cat,just in the past week I have noticed my cat scratching more and seems to be biting his hair out around his legs. My cat is solid white, and  noticed how much hair was gone,and could see the pink in his skin. My cat stays indoor so I know fleas would not be the main reason. My cat seems to shed a lot,( and would appreciate a suggestion on how to control that) so it seemed normal for some hair loss, but this is really looking intense and I am beginning to worry. I noticed tonight there were patches of hair loss on all legs front and back. Any suggestion  on what could be causing this?

Answer
This cat is obviously itchy and that's why the hair is being pulled out.  YOu can try givine the cat some antihistamine, like chlorpheniramine, but usually the cat needs to be seen by your vet for a long acting steroid shot for skin allergies.  Cats can be allergic to many things in their environment other than fleas.  Some cats will shed less if they are on an Omega3 fatty acid dietary supplement (fish oil).  Ask your vet for a veterinary product that is balanced for dogs and cats.