I have a female chiquaqua....

Question
I have a female chiquaqua.  she weighs about 3 pounds.  For the past week she has had what appears to be a cyst on her bottom.  It is not on her anus but to the left of it.  At first it seemed like an underskin growth but now it is open and running pus and is still swolen.  She is eating well but holds her left leg up when walking.  Have you any idea what this may be?

Answer
This could be an abscessed anal gland.  These glands live on the side of the rectum and they add scent to the stools.  When the openings of the ducts get blocked, the glands rupture to the surrounding tissue and get infected.  Then they open up and drain.  This requires a surgical correction by the vet.