Believe it or not, dogs can have allergies just like people. They can experience seasonal allergies; allergies to food; allergies to dust, mold, and dander (including people, cat, and dog dander!); insect bite hypersensitivities; and allergic reactions. Dog allergy symptoms are usually a little bit different than what is seen in people, so it isn’t always obvious that your pet is dealing with an allergic disorder. Read on for additional insights into allergies in dogs.
What Are Dogs Allergic To?
Common dog allergies are food, pollen, insects, mold, and dust. According to several studies by veterinary scientists, foods that cause allergies the most (in order of frequency) are beef, chicken, lamb, and wheat. Less common food allergies include soybeans, milk, eggs, corn, and walnuts. Flea bite hypersensitivity is by far the most common insect allergy that dogs experience, but mosquitoes and mites (e.g. Demodex mange) are also the cause of insect allergies in many dogs. Pollens, mold, and dust are common allergy culprits in dogs as well. Even more surprising, dogs can be allergic to more than one allergen, making diagnosis and treatment a bit difficult for some pets.
Dog Allergy Symptoms
Unlike people, most allergies (even food allergies) in dogs cause itching, skin infections, and ear infections. Dogs will often chew or lick their paws and scratch their ears, sides, or bellies. The skin and ears may look red; become thick or swollen; develop sores and flakes; or ooze. Less commonly, allergies can cause tummy troubles- vomiting, diarrhea or loose stool, gas, and a grumbly belly may be noted. The most common allergy to cause this type of gastrointestinal (GI) upset is a food allergy, which may occur with or without skin and ear problems. Coughing, sneezing, and watery eyes, seen more often with seasonal allergies in people, can also be a sign of allergies in some dogs.
Diagnosing Allergies in Dogs
In some cases, a veterinarian may become suspicious of allergies in a dog based on the history, symptoms, and physical examination. For example, if a dog has a skin infection whenever he has fleas, he may have a flea bite hypersensitivity type of allergy. If he develops skin and ear infections at certain times of the year, the veterinarian may suspect a pollen allergy.
To officially diagnose most allergies, blood tests (sometimes known as radioallergosorbent test/RAST test or allergen-specific IgE serology/ASIS serum test) or intradermal skin testing can be done. The blood test is easier to perform but may not be as accurate or trustworthy as the skin test. For the blood test, a blood sample is drawn from the pet and sent to a lab. The skin test involves injecting small amounts of allergens in liquid form under the skin. Intradermal skin testing is usually performed by a veterinary dermatologist because it is more difficult to do. Pets usually need to be off any allergy medications for at least 2 weeks before these tests can be performed.
Food allergies are more difficult to officially diagnose because the blood and skin tests cannot identify them well. Because of this, if a food allergy is suspected, a food trial will often be tried. This consists of either a novel protein and/or carbohydrate (protein and grain/starch the pet has never had before) diet, hypoallergenic diet, or a hydrolyzed protein diet for at least 6-8 weeks. No other food can be given, including treats and chewable heartworm/flea pills (Don’t worry, the pet can be switched to topical preventives).
Hydrolyzed protein is a type of protein whose structure has been broken down to a point where it cannot be recognized as an allergen by the body. This type of diet is most common for a diet trial because it is the least likely food to cause an allergy. If the pet’s symptoms improve after 8 weeks, a food allergy is likely the culprit. The veterinarian may then start adding back foods to determine what the pet is allergic to; however, some pet owners choose to remain on the special diet to avoid any further discomfort to the pet, rather than worry about testing new foods and dealing with the return of symptoms.
In some cases, eliminating the allergy will solve the problem. Preventing flea infestations and avoiding foods a pet is allergic to (usually by staying on a special diet) are common examples. In other situations, such as mold, dust, dander, and pollen allergies, and medications to control the allergies can be tried. Antihistamines; medicated sprays and shampoos; and steroids are common simple, first options. Steroids are not ideal long-term and are usually only used to control the initial itching and discomfort. If medications are needed long-term, allergy immunotherapy injections, Apoquel® tablets, cyclosporine tablets, and/or Cytopoint® injections may be prescribed. Unfortunately, though these options are often very effective when used regularly, they tend to be much more expensive than options like antihistamines.
Any infections will also need to be dealt with, so antibiotics and/or anti-yeast medications may be prescribed as well. Ear medications are often prescribed to clear up ear infections. If the ear infections are severe or happen frequently, a daily or weekly cleanser may be prescribed as well. Medications to clear up diarrhea or a persistent cough may also be needed (depending on the pet’s symptoms).
Know that as with many people’s allergies, canine allergies are very frustrating to treat. Many different medications may be prescribed before the most effective combination for the pet is found. Further, even if all the right medications, shampoos, foods, and treatments are done correctly, outbreaks of a skin or ear infection can still happen. It is important to follow all veterinary recommendations, go to all scheduled rechecks, and discuss any issues or lack of improvement as soon as they occur. This will prevent any prolonged discomfort for the pet and help him improve quickly.