Hello, sorry for the late update but I checked with my vet and it was overgrooming after all!
His hair has grown back and he seems happy again!
Thanks for all your help :)
Hello,
Thanks for responding so fast.
Yyes I have noticed him grooming a lot and biting more than usual.
I have treated him with flea ampoules so it doesn't seem to be that.
It started in the past week and no he never leaves the house.
Hello,
I noticed some sort of bald patches on my cat,
there's stil some hair so not entirely bald but you can see dark bluish skin. He's 2 years old , neutered and healthy.
I hope anyone knows what it could be before I head to a vet.
Thank you