cocker with skin problem

Question
i have a 5 year old cocker that has had problems with chronic ear infections and skin problems for almost 2 years.  after numerous medications at our original vet and hundreds of dollars later, we finally went to a new vet for a 2nd opinion, in hopes this would turn out different.  at first it seemed like things were progressing in the right direction, but the only real progress has been with his ears.  they did some scrapings of skin, blood work, which showed no answers.  his skin has sores on his face, chin, back, sides, on his genitals, and between his genitals and his anus.  they seem to start out with greasy skin and a small sore, then with a little licking and scratching, they quickly evolve into what i call a volcano.  they eventually scab over, but don't heal. if i don't bathe him twice a week with special shampoo (malasab), he starts itching and makes the scabs come off and the sores start bleeding.  i've been putting some neosporin on sores the last few days, and seems to be helping to keep sores moist and not dry and itchy.  i am giving him allergy pills twice a day, but they don't seem to make a big difference.  i am feeding him blue buffalo food (fish and potato), but although he seems to be a LITTLE better with this food, it doesn't make the symptoms go away.  i've been adding a bit of fat free  yogurt in his food twice a day, because i've read this could help with imbalance in yeast in his tummy...  (from what i've read, seems like he could have a yeast infection on skin...??)
he seems to improve with new medications, but never gets BETTER or turns around and gets bad again.  vet wants to do a biopsy, which i'm all for, but money is tight, and worried that after another few hundred dollars we'll be in the same spot as now, with no answers and no relief for one of the sweetest dogs i've known..  any help or advice you can give would be appreciated.

Answer
From your description, it would seem that the dog has an allergic dermatitis complicated by a skin infection.  That can also affect the ears.  HAs the gdog been on any cortisone type drugs for the skin disease?  If corticone helps, then it is probably an allergy and allergy testing is indicated to see what he is allergic to.  Topical cremes do not work well in dogs.  There is a spray called GENESIS that seems to relieve itching with a light mist applied daily.