Our previous basset had a flea bite allergy. Vet was treating him with all kinds of meds, turned out the next door neighbor's dog was a hunting dog and had fleas our dog would run back and forth along the fence with their dog playing.
Another thing to consider is a food allergy. On the basset rescue site I belong too there are several people who asked about pseudomonas ear infections -- indicated hard to get rid of, very painful. Several dogs had more of a yeasty smell to them, red "arm" pits, ear issues... They did elimination diets, switched to a higher grade food... One dog was allergic to corn, another to chicken...
Another thing to consider is a food allergy. On the basset rescue site I belong too there are several people who asked about pseudomonas ear infections -- indicated hard to get rid of, very painful. Several dogs had more of a yeasty smell to them, red "arm" pits, ear issues... They did elimination diets, switched to a higher grade food... One dog was allergic to corn, another to chicken...