Mouth, Nose Rash, hair loss Tried Everything, Getting worse

Hello, we are new here. Desperately hoping to find help. This is our girl Layla, 8. Overall, very healthy. Last fall we noticed some redness on the left side of her mouth, we kept an eye on it but it got worse. She has had allergy issues since we rescued her. We tried all of the vet's ideas: LID, homemade food, fish, NO chicken. NO beef. Mostly she would lick paws and bum. Anals done every 4 weeks. She started Cytopoint 4 months ago which seem to help the other issues, but her mouth is getting worse. 1 vet said it was her food bowl, we bought stainless steel as per her recommendation. No change. Another vet said it may be her food (Natural Balance L.I.D. Limited Ingredient Diets Sweet Potato & Fish Formula Grain-Free) She's been on this for a few years but mouth issue only last 6 mo. AND only 1 side. If she was allergic to food, wouldn't it be both sides?  I've read about lip fold dermatitis, but this is geared towards dogs with deep folds and hairy mouths holding food and moisture, she does not fit this description. Also, it looks like it's spreading to her nose, losing hair there and red. Vet sold us shampoo but 1st time using, she threw up. It must get in her mouth. It does not appear to bleed, but it's been very crusty to pet her and she's dropping lots of scabs. HELP...does anyone know what this is? THANK YOU all so much!    

How interesting.  One question: is this itchy?  Do you see her scratching or rubbing her nose where the hair is missing?

Thank you! It does not appear to be itchy for her, when the nose started showing signs of change, I did see her rub it , but not for quite a while and we are with her all day. The mouth area bothers her, sadly, it is on the left, the same side she has no back leg (yup, she's a sweet little tri-pod rescued @ 12 months-ish). Her little stump goes crazy as she bends her head towards the back as if she could scratch it. :(          The nose seems to be getting worse, mouth, maybe stable but no improvement. Thank you

Hello again - Thankyou for clarifying that.  I am not a dermatologist, but I wonder about autoimmune skin diseases.   Allergies usually itch and hair-loss is caused by scratching in these cases, but autoimmune conditions often don't itch and the boundaries between normal skin and mucosa are a common place for them to start.  Vets diagnose these by taking a sample for histology.  However this can involve an anaesthetic, so they may not take that step lightly.  For example, I would often do a scrape to rule out demodecosis (a more common non-itchy form of hair loss, caused by tiny mites in the hair follicle) first. I hear that you may be trying different vets but this often slows down progress with difficult cases; most vets will try to treat the simplest possibilities first.  If you then go away and try another vet, they will probably try to rule out a different simple thing, or the same simple thing another way, but if you then try a third vet, the first and second vets will simply assume that their treatment was successful and the third vet will start yet again at the beginning, so a lot of money can be spent without the necessarily more complex diagnostics ever getting underway. Rather, I would gather all the histories from any of these visits you have had  (the vets have to provide you with these on request) and take them, with your pet, to the vet at your practise who 'likes working up' skin cases (receptionists  help you out with this). Ask them specifically whether autoimmune diseases might be a possibility and if so, about what the next to identify them might be.

Thanks for your reply. That makes sense about multiple vets. Our vet's office has several dr's and it's not always the same, we will try and make appts with same Doc all the time. There was one that did seem more interested in a diagnosis than the other, I will ask receptionist to be sure. Appreciate the AI possibility suggestion. Thanks again :)

I will add, zinc deficiency often looks just like this. That being said it often affects one or both eye areas also. It is common in Huskies and other northern breeds, not so much in others but still is a possibility I am throwing out there. It can be a veeery slow killing machine ( like years ) if not treated, but is very easily treatable with supplements! My male Huskies jaw area looks exactly like this on both sides. I never saw him itch until one night I noticed he was in the middle of the night. He did for a few nights and hasn’t since again. His one eye has some hair loss and scabbing around it now, but for almost a year of him dealing with this it didn’t. This can also be caused by allergies or bacteria, amongst other immune and skin conditions. Are you using stainless steel or ceramic bowls and washing them? I can’t see this happening from a bowl issue considering the entire location. Again, throwing it out there. ( You can see my boys jaw area better in the first photo, I can find a better photo tomorrow if I remember lol. )

Will also add; to rule other skin issues out, I would suggest a skin scraping also, that can detect bacteria too.