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What’s Causing My Dog to Itch? Pets and Allergies

Our four-legged family members can feel the effects of allergies in the same way people do. We see three primary types of allergies in companion pets here at Foster Hospital for Small Animals at Cummings School of Veterinary Medicine at Tuftsdog and flea cartoon illustration University:  flea hypersensitivity, food allergies and environmental allergies.


Flea hypersensitivity 
is pretty straight forward. It occurs when pets have an allergic reaction to the saliva in flea bites. Dogs are mostly affected on the back half of their bodies (tail-head region and hind legs), where cats can have similar lesions, or groom excessively all over.
Treatment is good flea control, including environmental decontamination.

Food allergies, or what we call cutaneous adverse reaction to food, is much less common than people think and ironically can happen at any age. Most often, pets experience sensitivity to common proteins used in foods, such as beef, chicken, dairy, and soy. It is more likely that a dog or cat will become allergic to something they have eaten for a long time versus something that is new to them. Food allergies can look like any other kind of allergy, especially environmental allergies. Signs may include itching or digestive distress. Treatment requires identifying the offensive element of the diet and removing it. The only way to diagnose it is to do a strict elimination diet with a special food prescribed by the veterinarian that is used exclusively for at least 8 weeks. Blood and saliva tests are not effective in determining the specific allergen.

Environmental allergies (atopic dermatitis), those caused by allergens that are inhaled or come into contact with the skin, are by far the most common type of allergy we see. Pets can be allergic to things such as pollens, weeds, grasses, and dust mites. This type of allergy is often seasonal, with pets experiencing symptoms from ragweed in the fall, spring tree pollen in April and May, and dust mites most commonly seen in the winter months. As a result of these allergies, most pets become very itchy. They may show their itch by scratching, scooting their rears, licking or chewing their paws, and rubbing their face or eyes. Often these pets suffer from skin or ear infections that will recur unless the allergy is treated. Treatment options vary depending on the seasonality and severity of the pet’s disease, but include allergy vaccines, antihistamines, more targeted allergy-specific medications, bathing, and steroids, or a combination.

Just like humans experience allergies, pets can too. If you suspect your pet has allergies, talk to your veterinarian. While allergies in pets are not curable, they are very treatable and controllable. Once you’re able to determine the root cause of the allergic reaction, your veterinarian will be able to provide sound medical advice on how you can manage them so that your pet can live a comfortable and good quality life.