brittle nails

Question
I have a two year old female Min Pinscher.  About 6 to 8 months ago we noticed that her nails were cracked and flaking.  We took her to a groomer to have her nails trimmed.  Until that day she had never been aggressive when at the groomers.  I can only conclude that her nails really hurt because she nipped at the poor woman.  The nail trim did not help.  She started to limp around holding up her back feet. (Obviosly one at a time) and licking her nails ALOT.  We chose to upgrade the quality of her feed, both wet and dry.  At the same time we put her on a multi-vitamen and added Safflower oil to her dry food.  When two months when by and there was no change we consulted our vet.  That said to try an anti-fungle cream and an antibiotic.  None of this worked either.  By this time her nails started to break off completely.  At this time she has only 1 out of 9 nails on her back feet.  I started to talk to different groomers only to be told that I must hold her to much and that she needed to walk on hard surfaces such as cement.  This has not worked.  I am trying a new vet, but hoestly I am loosing hope.  Do you have a recomondations for me?  

Answer
There are several things that can be done to diagnose the problem.  The first is to have your vet do a nail bed biopsy and send it off to a pathologist for analysis.  The second is to have the vet do a skin scraping to look for both demodex mange and malassezia yeasts. Sometimes there is also a bacterial infection.  If the dog is chewing on its feet, it may be an allergy.  If these things  are not present, either from the pathologist or the vet, it may be a deficiency of Omega3 fatty acids and a supplement may be needed.