miniature schnauzer skin

Question
Gidget is my 5 year old miniature schnauzer.  About a year ago she developed a skin irritation along her back, from her neck to her tail.  Mostly it it scaling and tiny scabs but sometimes there are little puss bumps.  She's been treated twice with antibiotics & there are no mites under the microscope.  About the same time that the skin thing started, she began limping, alternating feet, and showing sensitivity near her toes.  She had all her feet x-rayed, blood test for lyme disease, besides regular blood work.  Nothing.  Then her toenails became brittle and most of them have fallen off.  She then had a blood test for her thyroid and that was okay.  She appears healthy but will lick on her paws sometimes.  Also she was diagnosed with pancreatitis just before all this started so she has a lower fat diet.  About two weeks ago she seemed suddenly miserable in the night; itching (she was never itching before), jumping around and looking at her butt, and wanting to be petted continually.  The vet feels it is related to her skin and put her on prednisone.  He also took care of her anal glands and since she seemed fine the minute I brought her home, I'm inclined to think that was more her problem this time.  Her skin began to clear up nicely but now is becoming very scaly again with a few bumps.  She's still on the prednisone every other day.  The vet says the next step is to have a nail bed biopsy done to see if Gidget's problem is an alergy.  Does that seem so be the way to go next?  How does this determine if it is an alergy?  Is the skin problem related to the limping and is the pancreatitis related to any of the other?  Please help with your opinion.  Thank you, Kim Jones

Answer
The nail biopsy is a good idea.  It tells the vet if it is a fungal infection, mange, or if there are cells called eosinophils, that indicates allergies.  You should also be bathing this dog with an antibacerial shampoo. Pancreatitis should not be that cause of the itching.