his been put on prednisone,and cephalexin.twice already in the last two months he is a Brittney spaniel who was recently hit by a car and underwent surgery in which they removed his joint.. Since then he has had this rash under his neck, DOnt think its a allergic reaction beause we have stopped all treats . he has been tested for mites and mainge and both came back negative. They said something about staph infection but Were not sure yet..