Environmental allergies tend to wax and wane, so, you may think a diet change is working….
Also the storage mite is in the same family as the common household dust mite that exists on the skin of all living things and is constantly being shed (airborne) including you.
Often the dog has allergies to both, not just one.
Below is an excerpt from an article that you may find helpful http://veterinarynews.dvm360.com/faqs-about-house-dust-mite-and-storage-mite-allergies?id=&pageID=1&sk=&date=
Where are storage mites commonly found?
These particular mites (Tyrophagus putrescentiae, Lepidoglyphus destructor, Acarus siro) are present in dry foods, cereals, grains, straw and cheeseāi.e., substances that can get moldy. Like dust mites, storage mites can cause nonseasonal signs, including pruritus, erythema and recurrent otitis in dogs and cats. They’re well-known in humans for causing asthma and allergic rhinitis (“baker’s lung”).
Data have shown that storage mites live in conjunction with house dust mites and can be found in bedding, mattresses, upholstered furniture and fabrics. One study in humans found storage mites to have overtaken dust mites as a leading source of allergy.
A popular misconception is that storage mites are present in bags of food or cereals from the manufacturer. In one study, out of 10 bags of dry dog food, one was found to have storage
