Oh poor you and poor dog. I have one dog with severe allergies and another dog with SLO (Symmetrical Lupoid Onychodystrophy) but I'm pleased I'm not managing both in one dog like you are as it's a lot for them to handle isn't it...
This is one of those conditions that, once you start researching, you realise is actually quite common. From the research I've done I disagree that it is diet related - i.e. it's not likely to have been caused by a dietary deficiency unless your dog is so intolerant to some foods that she has a severe gaps in her diet. However I do agree that in many cases it can be managed by making improvements to diet and supplements are a must, they really do help.
I have mentioned this topic a few times on here since my boy was diagnosed in Aug 2012 -
here is one of the early posts. Spelling is a factor when you're researching SLO and dyslexic fingers can really limit your search results so I usually cut and past the dratted name from one of the vet sites but if you search the ChampDogs site (using the box at the bottom of this page) for
Lupoid this is the bit we all usually spell right!!
I'm happy to answer questions as I'm managing the condition quite well nowadays but you might get the answers you need from my other posts too. Currently I give Viacutan Plus, an essential fatty acid supplement, and Onychotin tablets daily. These were prescribed by the vet but I buy them online as you don't need a prescription. I also use a bunch of other things that I'm certain help including plenty of fresh liver for the zinc and garlic and fenugreek tablets to counter infection. Incidentally have you had her blood tested, for possible SLO causes, but also to identify specific allergens? I think a York Test is always money well spent as a dog with severe allergies can't always wait whilst you try an elimination diet. Given that she is serious enough to need a GA for an ear clean and nail clip I'd want answers sooner rather than later :)
In the meantime give a daily paw soak in salted water and make sure you have plenty of Hibiscrub to wash her down after every walk. Make sure you have sharp nail clippers and also get a small easy to handle pair so that you can cut them close - I use some wire snipper things from my husbands tool box to good effect and I'll double check what they are actually called when he gets back.
Good luck at the vets tomorrow - I hope all goes well xx