Dog Allergies Hard to Diagnose

Q. I have a 5-year-old Labrador Retriever-Border Collie mix. I recently had her groomed and the groomer told me she has an ear infection and red toes, which she said is a food allergy. This is the second ear infection she’s had in a few months. She’s also licking her paws. The groomer told me to switch her food. How do I change over from one food to another without making her sick?

A. It does sound like your dog may have a type of allergy, but there’s no way of knowing if it involves food without checking out a few more things.
 
The most common type of allergy is to substances in the air that are inhaled (a disease known as atopy), such as cottonwood seed, mold spores, etc. In dogs, these types of allergies show up as skin disease, such as ear infections or redness between the toes.
 
Another form of canine allergies is food allergy. This can show up as either skin disease or gastro-intestinal disease (for example, frequent vomiting).
 
Some veterinarians will run a blood test to see what your dog is allergic to, but these tests are not 100 percent accurate. Another way to check for allergies is skin testing, which involves injecting a number of these substances into the skin to look for an allergic reaction. This test is usually reserved for dogs who do not respond to medication. It’s very difficult, expensive and challenging to diagnose the allergies through testing. Often, the best approach to dog allergies is to try different treatments and see which one works.

You certainly could try switching your dog’s food as a first step, but don’t be disappointed if you see little change. Your dog may be allergic to something she’s inhaling. Mix the old food and the new food together, and slowly increase the amount of new food over several days, to make the switch more gradual.

If the food switch does not work, see your veterinarian for some trial treatment with anti-inflammatory drugs or nutraceuticals. Frequent shampooing can also be helpful in cases of atopy because some allergens enter the body through the skin.