Dog allergies are often caused by the allergens found in pollen, animal dander, plants, and insects, but dogs can also be allergic to food and medication as well. These allergies can cause symptoms such as excessive itching, scratching, and grooming; rashes; sneezing; watery eyes; paw chewing; and skin inflammation. In many cases dogs have conditions, such as atopic dermatitis, that is associated with and may be caused by allergies.

When the dog’s body is exposed to one of the many allergens, the immune system reacts, or in most cases overreacts, and causes a hypersensitive state. Spay/neuter is known to affect the immune system of dogs; creating a greater risk for negative reactions to vaccinations, a higher incidence of some cancers, and a greater incidence of dog allergies. Banfield (a nationwide chain of veterinary clinics) acknowledges that within its patient population, spayed or neutered dogs are 3 times as likely to present with atopic dermatitis (one of the most prevalent expressions of allergies).92