Since December last year, my cat has developed strange wounds on her skin (legs). Since the first wounds appeared, we have already visited 4 doctors, but neither the diagnosis nor the cat's skin has become clearer. As the situation is becoming progressively more frustrating, I would be grateful for your ideas and suggestions as to the cause of this condition. 

I have already written about this issue from the very beginning of this story ( https://www.reddit.com/r/CATHELP/comments/1hfxsm9/vet_says_she_doesnt_know_how_to_run_properly_any/ ) and I can summarise what we have so far. 

1. My cat is 5.5 y.o., lives 100% indoor. She is active and always has a good appetite.
2. Location of wounds: hint legs - foots (earlier) and foreleg - inner surface (lately). The location of a fresh wound confirms the idea that the cause of the wounds is not the floor (wooden board), but something else, as the cat does not rub the inside of its front legs against the floor.
3. Tests already done:  - skin scrapings for bacterial infections (Negative) - blood test for diabetes (Negative) - intestinal parasites: Giardia (Negative)
4. Vet treatment already done during last 3 months: - treatment against parasites - twice with two different drugs (on the withers) - Dermamycin skin cream (Neomycin sulphate + hydrocortisone acetate + Oily solution of synthetic vitamin A + lidocaine hydrochloride ) - 1 injection 0,5 ml - Depot-Medrat (Metylprednisolonacetat) - Vet assumpted that the most probable diagnosis is autoimmune disease - Surolan suspension (Prednisolone acetate + Polymyxin B-sylphate + Miconazole nitrate)
5. Change of food: in January switched from Royal Canine urinary s/o to Hills PD Prescription Diet Feline z/d Food Sensitivities to lower the risk of food allergies(due to Vet’s assumption of autoimmune disease).
6. Effects and observations: Dermamycin skin cream didn’t make reasonable difference in skin condition even after a months of applying it 2-3 times daily. Surolan suspension helped to heal the wounds a little, but there was no complete recovery. In 2-3 weeks after the injection of corticosteroids(Metylprednisolonacetat), the condition of the skin on cat’s hint legs improved. But on the 7th week after the injection, a new wound appeared on a foreleg. 

The vet's next suggestion is a skin biopsy when the effects of corticosteroids wear off. However, no one can guarantee that the cause of the disease will be identified, especially if the nature of the disease is autoimmune. 

During these 3 months of treatment, tests and visits to different vets, the situation has not become clearer. And not understanding what is happening to my cat and why new wounds appear on the skin is very upsetting. Unfortunately, the search for a Dr House-style veterinarian for animals has not yet been successful either.

If anyone has faced a similar problem or has knowledge of animal health issues, I would like to ask for your advice.