Downeast Dog News

Why is My Dog Itchy?

By Loren Candito DVM DACVD | Sep 01, 2018

Portland Veterinary Specialists — Skin allergies are the most common reason that dogs scratch, lick, and bite at themselves. Dogs experience skin allergy signs such as itching, skin infections, and ear infections much more commonly than respiratory allergy signs (like sneezing and watery eyes). Skin allergies are most commonly due to one of the following causes: flea allergy, food allergy, or environmental allergies.

Dogs with flea allergies will have significant itching and hair loss, often directed at the back half of their body, in the “pants” region. Flea allergies are caused from a reaction to the saliva from flea bites. You will not always see fleas, but often there are signs of “flea dirt” on the skin, which is excrement from fleas that have fed on the pet. If there is black debris on the skin, an easy way to tell if this is from fleas is to place the debris on a white paper towel and wet it. If it is flea dirt, you’ll see a red tint (blood) on the paper towel. All dogs in general, but especially dogs with flea allergies, should receive year-round regular, veterinary approved flea-control to protect them against flea exposure (even in areas where there is a hard frost, wildlife can bring fleas close to the home, affecting pets during the winter). There are many safe and effective options for flea control. Your veterinarian can help you choose a product, tailored for your pet’s life style (ex. an oral product for dogs that swim frequently) and exposure (ex. products that repel ticks and biting insects for dogs in wooded areas).

Food allergies, also known as cutaneous adverse food reactions, occur in 10-30% of allergic dogs. Food allergy signs are present year-round. Proteins are the most common trigger for food allergies. Dogs can be allergic to individual carbohydrates or grains, but overall dogs do not experience a true overall grain or gluten intolerance. Some dogs with food allergies may experience ear infections or issues around their hind end, however signs can present all over the body. There is no accurate blood or skin testing to diagnose a food allergy (existing blood tests, hair tests, and saliva tests are extremely inaccurate), so the only way to diagnose a food allergy is with an elimination diet trial. Over the counter diets are not recommended for a true elimination diet trial due to concerns for cross contamination of ingredients, so it is very important to work with your veterinarian or a veterinary dermatologist to set up an appropriate home prepared or prescription diet trial that is both safe and balanced for your pet. When set up appropriately, a diet trial will give you a clear answer as to whether your dog has a food allergy within a short period of time (usually within 60 days).

Environmental allergies, also known as atopic dermatitis, are one of the most common causes of allergies in dogs (70-80+% of allergic dogs). This condition shares features with a eczema in people. Environmental allergies in dogs are triggered by allergens including grass, weed and tree pollens, molds, dust mites, or cat dander. Because allergies require lifelong management and there are no known cures, it’s important to get to the bottom of what is triggering the allergy signs. There are many symptomatic medications that can be used to make dogs feel better, but one of the safest, most direct ways to control environmental allergy signs long-term is via allergen specific immunotherapy. This is a customized serum created based on intradermal (skin) allergy testing, blood allergy testing, or a combination of the two, which is administered at home via injections or oral drops, to desensitize to the things your pet tests positive for. Some forms of allergy testing may be able to be performed by your general practice veterinarian, however many dogs will benefit from having their testing and immunotherapy regimen tailored by a veterinary dermatologist, to maximize the outcome.

Skin allergies can be extremely frustrating as we watch our 4-legged family members struggle with itching and infections from day to day, but there are many options you can work on with your general practice veterinarian to help your dog stay comfortable. If your dog’s allergies are challenging or you or your veterinarian feel your dog would benefit from evaluation by a specialist, veterinary dermatologists are specifically trained to identify the causes and find the best treatment options for individual pets.