A client writes in, "What is Pyoderma?"
Pyoderma means "pus in the skin". That is, infections in the hair follicles. Probably not fatal, but certainly very uncomfortable: sore and itchy.
Most are secondary to some other condition: An allergy or mite infestation or contact irritation or fleas can cause excess scratching. This damages the skin and opens the body's defenses, and bacteria that live on the surface with no problem can invade and cause problems.
A dog with low thyroid function or other systemic disease can have poor body defenses, also allowing the surface bacteria to do undue harm.
The bacterial infection in the skin needs to be treated with antibiotics and medicated shampoos, but you also need to find and treat the underlying cause that allowed the bacteria to get a foothold. Otherwise, the problem will only partially resolve and will come back.