My cat is licking patches of his fur off. What should I do?

My cat has been licking off patches of his fur.  I noticed one spot about 4 weeks ago, and thought maybe something was irritating him there, so I left it and have been watching it.  Now he has started doing this to many different areas.  He does this licking-biting thing and now has patches of baldness randomly, but especially on his belly.  I am really concerned and I want to make sure that he is doing better.  We switched his food somewhat recently, but I dont remember if it was before or after he started this licking.  I talked to the vet and she said to try a new food and see how it goes.  But I also want to help relieve whatever is causing him to do this.  Is there anything I can do in the meantime while I change his food?  He is a siamese, about 8 years old.  No previous health problems (although we took him in as a stray about 1 year ago so I dont have history beyond that).

I hope someone has some suggestions for me.

Thank you!

[opus88]

hi kell and welcome. this unfortunately is a very common problem that is often posted on...there is a thread with some links you can first read up on and it will give you some things to consider. I can than give you others but start there ok and let us know your thoughts.....♥

http://www.medhelp.org/posts/Cats/Cat-licks-off-hair-and-scratches-all-the-time-/show/1382158

[opus88]

I think this one maybe of more help to you, there are many others if you click on VIEW ARCHIVES at the top of this page and type in the words licking or scratching and look under dermatology....♥

http://www.medhelp.org/posts/Cats/Cat-licking-herself-bald/show/1374275

[tiggerpaws]

it sounds like stress to me. my cat started with stress last year after the introductiobn of a stray cat.  he would run crazy and bit at imagibary things near and on his boddy , he would spasm near his tail lower back.  he then started with crystals in his urin and almost died of a blocked bladder,  the condition is similar to OCD in humans and has a name call hyper  something or other. see the vets and speak about the stress route. my cat is on a daily antidepressant and other calming systems.  good luck