As the owner of an allergic dog, lots and lots.
Pyoderma is just bacterial infection of the skin, usually a Staph species. Staph is normally found on the skin and typically doesn't cause disease on normal skin. Underlying causes cause changes to the skin barrier and make it more susceptible to infection. The causes can be any allergic disease (food, environmental, flea), mange mites, seborrhea, endocrine disease, etc. So you should investigate hte underlying cause while treating the pyoderma. If it's not too severe, pyoderma is usually treated topically with shampoos or sprays. I personally love the Miconahex+Triz wipes and the shampoo. You can find them on amazon. Deeper infections need systemic antibiotics - at least 7 days past resolution of clinical signs. Rhaegar had pyoderma, especially on his feet. We allergy tested him and started allergy injections 8 months ago. We haven't had any of the same problems with pyoderma this allergy season (knock on wood). This is what his typical flare up would look like, pustules and papules: