Bald patch on inner arm

We have noticed our cat has lost his hair on his upper inner arm or armpit I would say, It doesnt seem to be annoying him at all but it does look like fleas may have bit him or somthing. I just gave him a dose of all worm fighter.

Do you guys want to see a pic or so you know what im on about?

Thanks heaps.

I'd have a vet look at it. Could be ringworm if loss of hair. And BTW you really should NOT be using over the counter worm medicines. You don't know what (if any) worms he has.

The vet should be giving that medicine. Worm medicine is poison - you need the exact dosage to give - something a vet determines.