He may be vomiting due to hair ball accumulation if he is 'barbering' his coat - ie grooming the fur off.
Children can pass ringworm to a cat which you can read about here
http://www.marvistavet.com/html/body_ringworm.html
or they can pick it up in the environment.
A flea might come home on someones clothing and cause a flea bite dermatitis too.
You can read about barbering here
http://www.northside-vet.com/pages/?coords=004,100
I'd plan on a vet check up for him ot see if an underlying cause for the fur loss can be found with a skin scraping or a check for parasites.
Hope this helps you!
We originally felt as if he was grooming his hair off, but then we started wondering about ringworm, because my daughter had a red spotty irritated patch on her scalp 2 days ago. It was oozie, flakey and has since cleared up some, but there alot of white flakes in her hair now. We thought she had bumped her head and maybe had scratched a scab, but now I'm not sure.
I will make an appointment with a veterinarian right away. Do I also take my daughter in to the doctor to get checked, since she had some skin irritation, or wait for a diagnosis from the vet ( ie. ringworm, parasites, etc. ). Do we all need to be treated? Can she go to school?
You might wait and see what the vet says - but you can always call your doctor and ask what they think.
Do read the article on ringworm in pets in the above answer.
And here is one for humans
http://www.dhpe.org/infect/ringworm.html
Cat Health, Behavior, Care Expert
30+ years cat owner, rescue, breeding, study of behavior & health care