Hi Jennifer,
The yeast (Malassezia) infection is secondary to the seborrhea. The seborrhea could be the result of a medical issue (like thyroid) or allergies, either environmental (flea bite dermatitis) or food related. If it were thyroid related, you might see issues related to weight loss or gain, as well.
First, I’d like to ask some questions: about how old do you think she is; how long have you had her; did she have the condition when you adopted her; has it ever improved or gotten worse (do you know what caused the change); how long has she been eating the Purina and has she ever eaten anything else? How are her stools?
Without knowing the answers to those questions, my first thought is that changing foods is such an easy way to see if that’s the culprit, that it’s worth trying.
I would choose a simple grain free food that contains a single animal protein. I would choose a protein that your dog hasn’t eaten. She’s been eating lamb, so maybe try something like duck or rabbit. Look for a food that that doesn’t contain other high histamine ingredients like tomato. I would avoid fish oils, in the event that fish is a problem as fish oil, in theory shouldn’t contain protein, but it isn’t a guarantee; same goes for chicken fat. Chicken is a common problem ingredient, so I might avoid all fowl for right now. Look for something that contains none of the ingredients she’s getting now.
I’d recommend Nature’s Variety Instinct Limited Ingredient Diet in either duck or rabbit. Some other good limited ingredient foods are Zignature, Back to Basics, Wellness and Earthborn Holistics. I’m not a huge fan of Natural Balance or California Natural, but both are affordable.
Figuring out food allergies or intolerance, is very time consuming and can be very frustrating. Keep notes on what you’re feeding and how she reacts to it and be patient, give the new food time to work. A true elimination diet is a lot of work and can be very challenging to do. Feeding a limited ingredient food is easier and keep in mind that treats can be problematic as well.
