Cat is biting himself

Hi all! New here but I've been searching like mad all day trying to find something about my Ripley. First, the really quick background. We have two kitties, both fixed, both with claws intact, both 100% indoor kitties. Tasha has been with us for almost 5 years, since she was less than 4 wks old. Ripley is 1.5 yrs old and he has lived with us for about 2 months now - he came from an adoption place.

Ok, so Ripley likes to sit in my lap and will lick my fingers but eventually starts biting. I tell him No and he stops - usually he goes back to licking. But sometimes, he starts biting his own legs. Front and back. I make him stop but it's kind of weird.

I noticed last night that he has a spot on one back leg and one front leg that are very raw, bald, and practically bloody. I would guess it's from biting himself even though I haven't seen him do it lately. Any ideas?

We just had a $500 month with Tasha (kitty IBS we think) and I'd really like to avoid an unnecessary trip to the vet although I'll definitely take him if I need to. Since he came home with us, we haven't changed his food, litter, or anything else. I'm coming up blank searching online. Thanks!

I have seen Buddy bite himself or at least his fur to groom and clean it, however I have never noticed him drawing blood or causing any damage, sorry.

I would first ask if you have de-fleaed him recently? If so what did you use? Biting like that can be a response to pain, an invasion of fleas, or other dermatitis like problems, or an allergy to food. It can also be a precursor to an afflicition called feline hyperesthesia (but not always)

He hasn't had any sort of flea treatment since we brought him home. I'm so forgetful about applying their Prevention stuff... They are both strictly inside kitties though and I haven't noticed any sort of fleas. Not to say it isn't a possibility.

He let me get a decent look at the back leg tonight - it really just looks raw, almost like a rug burn would look. He didn't act like it hurt when I was poking around checking it out.

I appreciate the suggestions - keep 'em coming. I feel like I just went through this whole "brain-storming for possible kitty illness causes" for the past month with my Tasha cat and now Ripley's chomping on himself. They need to give their kitty-mama a break!

Cats are very stoic when it comes to pain. He could be really hurting but his instinct tells him not to show it. I would take him in and at least get a skin scraping to see what is going on.

Just a thought - are you sure it is self-inflicted? As he is newish to the house, is the other cat picking on him at all? Or even in play fighting, they can pull fur out or nip quite badly. I discovered a raw patch on the back of Persil's neck, caused, the vet and I both think, by Ellie pulling a clump of fur out while they were rough playing. I kept it clean and put a little antiseptic on and it is now gone.

At first, I did think it could be from the other cat. And he does have one mark on his head that I think she caused. But after watching them play/fight, I've never witnessed any sort of scuffle that would result in him having sores where he does - it's really on the inside of his legs. When she swats at him, I've only seen her swat at his head/back/outer-exposed areas.

It is possible though that it's from Tasha. He doesn't act like those legs are otherwise in pain (or even like these sores are hurting) when I extend his leg, put pressure on it, rub it, etc. I'm definitely keeping a close eye on the two of them (and his sores), just in case.