Yorkie with chronic skin disease

Question
Dr. Gotthelf,
I have a seven y.o. yorkie with a chronic skin condition that worsens in the spring & summer. The circular patches begin as bright red macules, become flakey, then turn black. The patches begin as dime size then may become 3-4cm. It has been diagnosed as pyoderma, however it seems to me after numerous rounds of Abx. (cephalexin x 2 or 3 rounds, augmentin) that it would be gone. One round of Keflex was 4weeks. It improves with the abx but never resolves completely. The only time it was resolved was after a steroid injection and of course that was only a temporary fix. I bath her weekly with a chlorhexidine shampoo (have even tried the selenium shampoos). Do you think a round of doxycycline might help? Any advice will be greatly appreciated. Thank you for your time in volunteering to answer questions.  

Answer
Allergies are chronic problems, so as soon as the steroid wears off, the allergic skin disease and the pyoderma returns.  I would recommend after the shot to use a low dose of oral steroid like prednisone or dexamethasone to keep the skin reaction minimized.  Then the antibiotics will not be needed as often.  Continue bathing her and you might ask your vet about an Omega3 fatty acid supplement to help her skin.