My cat and hair loss...

[WildflowerMom]

My outdoor semi-feral cat is having some hair loss.   There are no scabs, redness, nothing.  Just straight hair loss.  He gets flea treatment monthly.  His appetite is fine, drinking water, acting normal.   What could be causing this?  I switched up his food because they were out of what he normally gets, but it’s still the same brand. Could that be it?  
Is there anything I can try at home first, besides finding his old food?  
He is semi-feral.  He will come up to me to pet him, but if I have to actually take him somewhere he may lose his mind.   He used to be my neighbors cat and she moved into assisted living and left him for me to take care of.  After he was used to her a while, she could put him in a crate to go get his shots once a year.  I believe he’s up to date still.  I really do not want to try to wrangle him into a carrier and to the vets office if I don’t have to.  

[stephanier.1765]

It could be over grooming. There can be a variety of reasons behind the overgrooming and it might take some detective work to find out what's behind it. My son's cat has a naked belly from overgrooming. They've tried a number of things but still haven't figured it out and they've been working at it for a couple of years. Hopefully, you have better luck. 

[Selkie]

That can be a symptom of a thyroid problem.

[RootAnn]

Can you post a picture? Is he losing it in clumps or can you tell?

I hope it's not ringworm.... 

Edited May 3, 2021 by RootAnn

[WildflowerMom]

I’ll try to get a picture tomorrow.   I looked at pics of ringworm in cats and it looks nothing like that.   It just looks like the hair is thin, nothing else looks off.