Expanding Sore on an Older Bichon's Side
by Kent
(Ogden Utah usa)
Otherwise dog is healthy, good appetite and moves around fine.
A sore that keeps growing and loses hair over a couple of weeks may be an infection, a hot spot, or a skin tumor that has ulcerated. Older dogs are more likely to have tumors.
Have your vet examine it. If it doesn't clear quickly with treatment, ask for a biopsy.
This is general information, not a diagnosis. Please follow your own vet's advice.