Just like people, dogs can show allergic symptoms when their immune systems begin to recognize certain everyday substances—or allergens— as dangerous. Even though these allergens are common in most environments and harmless to most animals, a dog with allergies will have an extreme reaction to them. Allergens can be problematic when inhaled, ingested or contact a dog’s skin. As his body tries to rid itself of these substances, a variety of skin, digestive and respiratory symptoms may appear.
Allergic dogs may also suffer from secondary bacterial or yeast skin infections, which may cause hair loss, scabs or crusts on the skin.
Any dog can develop allergies at any time during his life, but allergic reactions seem to be especially common in terriers, setters, retrievers, and flat-faced breeds such as pugs, bulldogs and Boston terriers.
A few common allergens include:
Yes, but it often takes some detective work to find out what substance is causing the allergic reaction. Dogs with a food allergy will commonly have itchy skin, breathing difficulties or gastrointestinal problems like diarrhea and vomiting, and an elimination diet will most probably be used to determine what food he is allergic to. If your dog is specifically allergic to chicken, for example, you should avoid feeding him any products containing chicken protein or fat.
Please note that food allergies may show up in dogs at any age.
Visit your veterinarian. After taking a complete history and conducting a physical examination, he or she may be able to determine the source of your dog’s allergic reaction. If not, your vet will most probably recommend skin or blood tests, or a special elimination diet, to find out what's causing the allergic reaction.
If your dog’s itchy, red or irritated skin persists beyond initial treatment by a veterinarian, allergy testing, most often performed by a veterinary dermatologist, is likely warranted. The diagnostic test of choice is an intradermal skin test similar to the one performed on humans.
The only way to diagnose a food allergy is to feed your dog a prescription or hydrolyzed protein diet exclusively for 12 weeks. The importance of not feeding your dog anything but the diet cannot be emphasized enough—that means no treats, table food or flavored medication. This diet will be free of potential allergy-causing ingredients and will ideally have ingredients your dog has never been exposed to. He’ll remain on the diet until his symptoms go away, at which time you’ll begin to reintroduce old foods to see which ones might be causing the allergic reaction.
Please note, many dogs diagnosed with a food allergy will require home-cooked meals—but this must be done in conjunction with your veterinarian, as it requires careful food balancing.
The best way to treat allergies is to remove the offending allergens from the environment.
Since certain substances cannot be removed from the environment, your vet may recommend medications to control the allergic reaction:
Chronic exposure to inhaled irritants (including cigarette smoke) may be a cause of bronchitis in the dog. Bronchitis is characterized by a persistent cough due to inflammation of the airway and excessive mucus production. Treatment may include medication to open breathing passages, antibiotics and anti-inflammatory agents. Please remember, your pets should not be exposed to cigarette smoke.