Vet will probably call it staph infection - may be
Natural B-complex will help with recurrent problem.
Do not use synthetic - natural will read B12 (methylcobalamin - not cyanocobalamin) and "no-flush" niacin (B3 - fights bacteria).
My dog had this in summer, much worse though.
Also treat topically with goldenseal tea - 1 cup boiling water per bag bring to room temp (no need to take bag out) add a splash of organic apple cider vinegar - goldenseal natural antibiotic and antibacterial as well the ACV antibacterial and will balance skins PH.
He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours, faithful and true, to the last beat of his heart. You owe it to him to be worthy of such devotion. - Unknown