Itching is a very common problem in dogs, and it can be a difficult and frustrating issue to resolve. Although there is an indefinite number of reasons that Fido may be itchy, today’s column will discuss the two most common causes of itching: external parasites and allergies.

Fleas and mites are two external parasites that cause itchy skin. Fleas can usually be identified by the naked eye, although they are very small and can be easy to miss. There are many types of flea prevention and treatment available, so discuss the options with your veterinarian to determine which is best for your pet.

Mites, which cause the condition known as mange, are less common than fleas. They are microscopic and are identified by a test called a skin scraping. Treatment depends on the type of mite identified. 

Allergies are very common, and are usually more difficult to manage than external parasites.  Allergies occur when the immune system “overreacts” to substances that are usually harmless, known as “allergens.”

Dogs with allergies usually have red, itchy skin, hair loss, or recurring skin and ear infections. Allergies can be to anything, although the most common triggers are parasites, food, and environmental substances.

Flea allergy dermatitis is the most common skin disease in dogs. Fleas normally cause itching, but in dogs with a flea allergy, the itching is far more intense. In a flea-allergic dog, even one flea bite can trigger a severe allergic reaction. Therefore, year-round flea control is critical in these dogs.

Food allergies are fairly common, and may occur as a reaction to any component of food, including proteins, carbohydrates, or dyes. Diagnosis is made via a “food trial,” which usually involves feeding a prescription hypoallergenic diet for several weeks.

Many over-the-counter diets claim to be low in allergens, but these foods often contain traces of common allergens. Therefore, a proper food trial should implement a prescription diet.

Environmental allergies cause the condition known as atopic dermatitis. Atopic dermatitis commonly occurs in response to pollen, mold spores, and dust mites, although any substance in the environment may serve as an allergen.

Atopic dermatitis is suspected once external parasites and food allergies have been ruled out. Allergy testing, either by a skin test or blood test, provides a definitive diagnosis.

To further complicate matters, dogs with allergies often suffer from secondary skin and ear infections. Every animal has “normal flora,” or harmless microscopic organisms, on their skin. When normal skin barriers are compromised, as with allergies, the normal flora (most notably bacteria and yeast) reproduce excessively and cause infection. It is therefore important to treat secondary infections as well as underlying allergies.

Unfortunately, there is no cure for allergies. They usually require life-long management. Your veterinarian will evaluate the cause and severity of your pet’s allergies, and will work with you to determine an optimal treatment plan, so Fido can finally stop scratching and you can get some rest.

Dr. Kellly Sulik owns and operates Animobile Mobile Veterinary Services in Tryon, N.C. She can be reached at animobiledvm@gmail.com.