We've been on a food trial since mid February with a hydrolyzed protein kibble (salmon). I thought we were going to begin doing the introduction of new materials but the vet doesn't seem open to that. She says that Sky will have to stay on this diet forever. I think I might have to go rogue and do the tests on my own, but I'm still frustrated that she still looks unwell on various days .

I don't have the problems that you've had but I've had to review what I'm feeding my pups.  I'm an old country boy and haven't fed much except Purina Dog Chow for years .. but my dogs are having a revolt and not eating.  Personally I think it's something wrong with this bad / lot of food.  I put some out back and even the coyotes aren't too interested - now that's bad since they'll eat almost anything!

I'm never impressed with any doctor - human or vet - who says that we have to accept the status quo when the status quo isn't where my dog should be.  As @TwisterII suggested, it's all too easy to see your dog 'in love' with some food only to find out later that she's (er, he's) allergic to something in it.  Go rogue, try and see what you can work out!  But do it carefully and over a time span that let's you know what's good and what isn't. Simplify your menu as much as possible and also consider those 'non-meal' additions like treats, etc.

You might want to talk to the folks at Fromm Family Foods ... I've had several conversations with them.  First over the food that I was feeding Sasha because I couldn't get her weight down and now that these two are revolting about something that meets their needs.  (( Adult formula .... ))

We use essence LID but before spider all my animals (dogs, cats,horses) ate purina. Pets global is the owner of essence. Its a good company and if you reach out to them they have will send samples go over nutritional needs specific to your dog, and they have never had a recall.

My mom lives and breathes science diet. I was never impressed with it but she had the added requirement of dog food being kosher and it is one of the top kosher dog food brands.

Thanks very much for the advice, everyone! I also had similar feelings about the status quo decision, @aljones, since we hadn't done any tests otherwise!

So yes, I am starting to go rogue. She is getting peanut butter treats again and I have begun the transition off Tylan. I will contact Fromm and Essence. I did an in depth look at Fromm's dog food options some time ago and besides the vegetarian, it seemed many of them had chicken by products or weren't single protein, but maybe I missed something. My brother uses Fromm for his chihuahua and she loves it.
I really had liked the salmon purina pro plan for sensitive stomach, too. I'll probably test new brands and the other food options like dehydrated treats (I used to give my old husky Stella & Chewy's dehydrated treats).

Just a small update - i finally got the ultrasound and nothing showed up. She's also developed a terrible case of skin blister/scabbing on her mouth and forehead. The specialist said she must have just scratched herself and the next day it had clearly spread and got worse. Another vet thinks it's chelitis but not sure that accounts for the scabs/crusting on her head (and a spot on her shoulder). The specialist is still insistent on her staying on hypoallergenic food but I'm going to try new foods and I've already begun reducing her tylan powder dosage.

Hopefully we can figure out her skin issues soon so her paw surgery doesn't get postponed further (an infection would have compromised her!).

Poor girl. Was she checked for zinc issues? Low zinc can cause hair loss and scabbing usually around the mouth is where it starts. It's less common for it to move other places but with her dietary issues her body might be super low and it's exacerbating the hair loss.

Huh. No that was never brought up but i knew zinc deficiency was a thing. I didn't know that's how it manifested. I'm going to look into supplements. She had a primary care visit last Thursday night and they just attributed it to allergies. They really have no idea why she's getting bumps on her nose and redness on her inner eye, either. She got a cytopoint injection that seems to have done nothing yet to quell her scratching.

This morning she scratched her ear raw in an almost perfect circle she has surgery this Thursday so no more primary care visits for awhile.

If she's just randomly scratching through parts of fur and they aren't just falling off then it's likely allergic reaction to something, so maybe think through anything new she might have eaten or any grass sections she might like to look through that might be going to seed right now. With it mostly being upper body concentrated it might be something she likes to look into that doesn't agree also. My male is allergic to a couple types of grasses which make his feet break out in the early parts of summer while it's at it main growing period. You can do an environmental allergy test. they have decent accuracy. The food allergy tests aren't really worth the money though.

I should have responded sooner, apologies. Just been overwhelmed as we had a rapid amount of vet visits and I postponed her surgery. @TwisterII you were right, it was a zinc deficiency issue. I'm pretty pissed. I asked awhile ago about this and I was brushed off. I asked again recently and was told it still might not be that. Asking internal medicine, i was told in the early stages of these skin lesions they were just scratches and to take her to a behaviorist for acting unwell since they couldn't figure out the reason...

RAWR. Anyway, the dermatologist biopsied her and confirmed. Sky is on steroids and zinc gluconate now. I hope this formulation is the right one for her but only time will tell. Her stool is kinda off at the moment, though. Just glad that for once I got a real diagnosis.

I really meant to respond to this as soon as I saw it but being an old man, my railroad doesn't run as well as it used to.
I'm really glad you've gotten a resolution to this, that last picture - *that* on a dog! - really hurt. They can't tell you what's wrong but they really need to find a better way to tell us that something is.

So, please to follow up and let us know how things are going ... don't let little things like life get in your way.

Im in the mad at my vet clinic. Different reasons. I also a year later finally got a concrete diagnosis. Hope the zinc works. I completely understand your frustration about being brushed off and then told it was what you brought up the first time.

So sorry to hear that @Lostmaniac, hope your pup is on the mend!

Thanks @aljones, trying to stay tough/calm, some days are harder than others

On the mend is out. Its a hope it doesn't get worse situation. Compunded by 3 messages to csu cardiology for a consult and no call back. Suspected epilepsy turned out to be heart murmur and slight enlargement. Its just something the i brought up and im not sure if it would be less bad if it was caught 18 months ago when he just wasnt acting right. New vet was extremely thorough and thought it was thyroid but caught the murmur and did an xrax. 7 appointments later, over $1000 and he has the beginning of dcm.

Sorry about the rant. Im devastated about splinter. And spider knows and is being weird, and i wouldnt be shocked to wake up and find shadow dead on the couch any day now. The horror of 4 senior dogs when 2 have medical problems and one is a mental case totally reliant on splinter.

@Lostmaniac do not be sorry. It's frustrating and soul draining and sometimes/often that's what one needs to do. You are doing right by these kids who are living their best life even if it's not the greatest for each anymore. I'm so sorry about all of the challenges and they're so smart, they know something is up. You guys are in it together. We're here to support!

Also, I totally understand what you mean about "what if this has been caught sooner". I try not to think about it too much but it is hard not to! We've been at this for 9 months, I can't imagine double the time (but I guess it will happen...). I also thought I wouldn't have to see a vet so frequently after my older one passed and yet here we are with a 'baby' with all the issues.

Anyway, appreciate everyone who has stuck with all of my posts so far (and rants, too!).