clumps of hair falling out

Question
for the past 2 weeks my cat has been losing hair in clumps which started in the middle of his back to the beginning of his tail which has ended in partial baldness, small patches here and there with little red spots or bumps where the skin is showing. He also had been throwing his food up like it had not been chewed up and swallowed.  No hard stools just diarrhea. possible increased appetite and increased thirst. I notice he drinks a lot of water

Answer
There could be many things going on.  It's really hard to say since he is having so many symptoms - it could be anything from kidney failure to thyroid problems to allergies.  I would definitely recommend taking him to your vet as soon as possible so they can do an exam and blood work to find out exactly what is going on.

Amanda