Itchy Puppy

[Crazy4kitties]

I have a 13 week old long hair chihuahua puppy who has a serious itching problem! Ever since I brought her home 4 weeks ago, she has been scratching non-stop. She even chews her fur to the point where it is starting to get thin! The itching is mostly on her back and shoulders, she has chewed the fur on her hindquarters/sides where she can reach it. It isn't fleas, she's white and I inspect her daily - no flea dirt whatsoever, she's spotless. I suggested Cheyletiella to the vet, as it's the only thing I've seen which matches her symptoms. The vet said she didn't see too much dandruff (even though I can see it..I don't think she looked hard enough), and when they used the flea comb and had a look under the microscope, they didn't see any mites. They sent me home with Advantage Multi, but she thinks it is likely food related.

The breeder was feeding Iams (yuck), I have been feeding her Now! Grain free small breed since I brought her home. The vet suggests a food trial if there is no improvement after the next dose of Advantage (which is due in three weeks). I refuse to feed the z/d or any prescription diet for that matter.

I'm almost hoping it isn't Cheyletiella, as then I'll have 5 cats to treat as well ($$$!), and a ton of housecleaning to do!

Any suggestions besides mites or food allergies? She doesn't chew her paws or the base of her tail, her ears look great, it's mostly just her back that seems itchy.

Just for reference, the ingredients in the Now grain free are:

De-boned turkey, potato flour, pea, apple, whole dried egg, pea fibre, tomato, potato, flaxseed, canola oil (preserved with mixed tocopherols, a source of Vitamin E) , natural flavor, salmon, de-boned duck, sundried alfalfa, coconut oil (preserved with mixed tocopherols, a source of Vitamin E), carrots, pumpkin, bananas, blueberries, cranberries, raspberries, blackberries, papaya, pineapple, grapefruit, lentil beans, broccoli, spinach, cottage cheese, alfalfa sprouts, dried kelp, flaxseed, calcium carbonate, dicalcium phosphate, lecithin, sodium chloride, potassium chloride, vitamins ( vitamin E supplement, L-ascorbyl-2-polyphosphate (a source of vitamin C), niacin, inositol, vitamin A supplement, thiamine mononitrate, d-calcium pantothenate, pyridoxine hydrochloride, riboflavin, beta-carotene, vitamin D3 supplement, folic acid, biotin, vitamin B12 supplement) , minerals (zinc proteinate, ferrous sulfate, zinc oxide, iron proteinate, copper sulfate, copper proteinate, manganese proteinate, manganous oxide, calcium iodate, sodium selenite), taurine, DL-methionine, L-lysine, chicory extract, Lactobacillus acidophilus, Lactobacillus casei, Enterococcus faecium, Bifidobacterium thermophilum, dried Aspergillus niger fermentation extract, dried Aspergillus oryzae fermentation extract, yeast extract, yucca schidigera extract, marigold extract, garlic powder, L-carnitine, dried rosemary.