I haven't had much of a problem yet as Chaos is still a puppy. I have read numerous posts on her about yeast being the cause of the infected wrinkles. Use some desitin or gold bond after you clean the wrinkles. And yes mam, food can be the cause of the tear stains! You may want to try Fromm food, its a popular choice on here and helps tremendously with skin, coats, and tear stains. Also alot of people have said Avoderm helps with tear stains as well. I switched to Fromm and love it so farGood luck