Veterinary questions? Ask a Vet for Answers ASAP
Hi there, this is Dr Linda, a UK based vet.
I'm sorry to hear he is not himself today and understand your concern.
Hamsters are generally good at 'pretending they're fine' even when unwell. So, when we can tell something isn't right, they are usually quite poorly.
The fact that he isn't eating as much as producing less stool is a red flag. Rodents can develop 'gut stasis' whereby their gut slows down and fills with gas. They need to be constantly eating to prevent this.
Given all you have said, I would advise a vet visit now if at all possible.
Ideally, he needs to be examined and will probably be started on medicine such as pain relief and gut motility drugs as well as fluids.
It may be that he is unwell and that this has led to a flare up of mites. All hamsters have a few mites but these are usually kept in check by their immune system. When poorly, they can develop a mite infestation that makes them very itchy.
We would also consider a bacterial or fungal skin infection.
Another possibility would be an allergic reaction or contact dermatitis from something in the environment.
Certainly, the vet will examine his skin when checking him over, to determine what may be going on.
Not at all and wishing him all the very best.