Open wounds

I have a 7 year old mixed breed dog who seems to be in good health except that she seems to be developing open wounds. More that a year ago, she formed a huge bump on her back. We took her to the vet and got the puss drained. However, the wound never healed and it constantly drips with blood. A few months ago, a tiny hole appeared around that same area. Again we took our dog to the vet and the vet said that it is nothing to worry about and sent us home with some anti-septic cream. A few weeks ago, another tiny whole appeared and both holes look like puncture wounds but we have nothing around our garden that could have punctured our dog. It seems like her skin is just opening up with these tiny holes and blood just keeps on dripping out of them. We have bought her the colar to prevent her from licking or biting her wound yet it is still not healing. Her appetite is normal and she still runs and barks like she always has. What should we do? I'm really worried that it will get infected.

[Jim Humphries, B.S., D.V.M.]

I would get a second opinion.  This should not be continuing.  If it is an infection, then we did not clear it up in the first place.  If the source of infection is a deep sub-Q or foreign body (like a thorn etc) then that needs to be explored or x-rayed.  If it is a skin tumor and these can cause secondary infections, then the tumor needs to be diagnosed and probably removed.  

If it is an outside dog I would be concerned about spider bites etc.  This sounds like a deep wound infection so it is probably not pyoderma or a "hot spot".  

A more detailed exam is needed to get a diagnosis, then proper treatment and follow through should get this cleared up.  Let us know what they find.