What you describe sounds like an allergy, and it could be a yeast infection. Willy gets this, a skin yeast infection, if he has any grains at all, so I must feed a grain free food. Without seeing a photo, what you describe may also be hot spots, but the groomer would have known the difference, so I'd go with allergy.

Earthborn Holistics offers some grain free formulas, all their ingredients are human grade, the food is made in a facility which prepares human food, and they have never had a recall. That is what I feed my dogs and cats.

Food allergies are often an allergy to the protein source, the most common being chicken and beef. So use a food with an alternate protein source: bichon, elk, duck, rabbit. As with humans, a dog can develop an allergy at any time, so it 'could' be the food.

Here is their link: http://www.earthbornholisticpetfood.com/us/ Hold your cursor over DOG and you will see a pop up menu, they offer 4 grain free formulas. Great Plains is bison based.

Be sure to use grain free treats as well. These include: sliced raw sweet potato (cleans teeth too!), sliced apple, raw carrots, green beans. You can also buy Plato Farmer's Market Salmon and Vegetable, but NOT the strips as those are not grain free.
http://www.platopettreats.com/produc...ee-farmers.php

The most common treatment from a vet is going to be a steroid, like prednisone. This is very hard on the dog's liver and should be used sparingly so it is best to figure out what the cause is. Prednisone may increase appetite and thirst, and increased thirst can lead to increased drinking and hence . . . increased peeing.