Bald skin on leg

My cat, Elvis has a bald patch on the back of his leg, when I try to touch it he’ll react by biting me or running off. he has hip dysplasia, had surgery on his right leg - the one that has this pink bit on his leg. he’s a 7kg chunk, allergic to most things - food & medicine and absolutely hates the vets

Hello - I'm sorry to hear that Elvis is having a hard time.  There are various causes of elbow-biting that are local to the skin, such as mites and possibly ringworm, that your vet might want to rule out.  However, one of the strong differentials here might be pain - especially given that Elvis is already known to suffer from hip dysplasia.  Cats haven't evolved to show pain to humans and it may not present as limping or crying out, which a lot of owners expect.  Overgrooming is a typical pain response, but not always where the pain originates from; hocks are easier to reach than the hips.  It is definitely worth approaching your vets with this issue and may take a few appointments to get to the bottom of.  I don't know enough about Elvis's individual case to comment, but a review of his arthritis and pain releif may be one channel of enqiry.

As to Elvis hating the vets, in general this is a common issue that is difficult address; some clinics however, are much more 'cat friendly' than others, so it may be worth doing some research on this matter.  If a cat may have underlying joint pain, this can make the carrier-experience worse so a large cat carrier and a clinic that will allow time for Elvis to recover from the journey and so on before being examined, might be worth seeking out in order to maximise the value of the consultation.  I hope that something there is of help.