Black smelly pimple

My dog was diagnsed with skin allergies last year.  She has had this hard black pimple type bump on her back near her mid spine for about 1.5 years that doesn't get bigger, but also doesn't go away.  When I touch it, the top layer comes off, and it has a greasy feel and foul smell.   That's the 1st bump.  Recently, I noticed a new bump about 3 inches below the black one.  It is white and hard, but nothing comes out when squeezed.  Both are small, about a centimeter or 2.  They seem to bother her slightly when touched, but not much.  Activity level, appetite, and bathroom patterns are the same.  I hadn't seen the white bump last time she went to the vet, so I didn't bring it up.  All tests (except full blood panel, which i didnt do this time), came back normal.  Any ideas on what these two different types of bumps may be?  I have an appointment with a dog dermatologist at the animal medical center on 12/30/10.   Thank you for your help!

[Dr. Carol Osborne, DVM]

These canine skin lumps both sound benign and not a cause for concern. The white"head" is likely just that and your regular vet can simply express this. You can probably also do this your self. The black "pimple" also sounds like a benign lump and these are quite common and again not a cause for concern. Thuja, a homeopathgic remedy can be rubbed onto this daily for natural resolution.
Dr Carol Osborne, DVM.