Black pimples and black crust

I happen to notice something unusual on my dog's vagina today..she has a few black bumps which look like pimples.  One pimple/bump had normal (yellow) colored pus in it.  I looked around the area and noticed, hidden under her hair/fur, she had some black crusty matter.  I did not see any discharge or smell anything abnormal.  She has been acting completely normal, and I haven't noticed anything bothering her (straining to urinate, excessive drinking/eating, etc).  She was in heat towards the end of last year and has not had babies in years.  The only bit of information I have to offer that may (or may not) be related is that she has an ear infection currently (brown/black ear wax) which I've been cleaning and giving her some "Remicin" for.  Also, she doesn't usually come into contact with other dogs but last week our neighbors dogs greeted her and did what all dogs do...sniffed around the private parts.  I wonder if somehow he got some dirt/bacteria on/in to her.  Any help/suggestions would be much appreciated!

[Kimberly Coyner, D.V.M., DACVD]

What you are describing does sound like a localized bacterial skin infection, often due to the increased moisture and skin folds around the vulva, +/- an underlying allergic skin disease (something to consider since she is also being treated for an ear infection and recurrent ear infections are a common manifestation of underlying allergies in dogs). The infection is due to overgrowth of normal skin bacteria,and not exposure to other animals. You can try topical antibacterial creams and shampoos, but if the dermatitis persists, then please recheck with your veterinarian, as systemic antibiotics may be needed.
Kimberly Coyner, DVM DACVD
www.dermvetvegas.com