Itching & Allergies in Dogs

by Dr. Susan Hore, DVM January 12, 2017

Nothing can be more frustrating for dogs, their guardians and their veterinarians than a chronically itchy dog. Allergies are an overreaction of the immune system to things such as parasites (i.e. flea allergy dermatitis), things in the environment (such as pollens, dust mites) or to certain foods.

Canine atopic dermatitis refers to allergies to things in the environment, with the most common allergen being house dust mites. Atopic dermatitis affects about 10% of dogs and is especially prevalent in terrier breeds. Symptoms usually begin between 6 months to 3 years of age and often start seasonally (depending on the allergen). Itching most commonly occurs on the face, ears, legs or belly. Almost one quarter of dogs with atopic dermatitis also have a concurrent food allergy.

Adverse food reactions are responsible for anywhere from 15 to 46% of itchy skin problems in dogs, and often present before the dog is a year old but can develop in older dogs as well. About one third of these dogs will also have some gastrointestinal symptoms. Surprisingly, most adverse food reactions are not associated with a sudden change in food.

Allergies are becoming more common in dogs and people, and although allergies have many risk factors, changes in the gut microbiome are likely triggers. The environment and diet of pet dogs has certainly changed in the last 100 years. Nowadays, most dogs live indoors in a much more sterile environment versus the outdoors. Many are fed commercially prepared diets, limiting their exposure to live bacteria. It is quite common for puppies to receive antibiotics, which adversely affect the microbiome. We know how important the gut microbiome is in developing and maintaining a competent immune system.

It is easy to see how a damaged gut can lead to increased permeability of food antigens and a resulting abnormal immune response to certain foods. But this overreaction of the immune system can trigger excessive inflammation - not only in the gut, but anywhere in the body.

Studies in people have shown that the microbiome differs between people with atopic dermatitis and those without. Studies have also shown that the gut microbiome of children who later go on to develop atopic dermatitis differs from those that don’t develop the condition. In a dog model of atopic dermatitis, early exposure to probiotics had beneficial immunological and clinical effects. And in another study with dogs, the pups of lactating bitches fed a commercial diet were twice as likely to develop atopic dermatitis than the pups of lactating bitches fed non-commercial foods (such as meat, eggs, and dairy). Again, the possibility of increased exposure to bacterial diversity is thought to be important in developing a healthy gut microbiome.

A prebiotic supplement, such as MSPeubiotic®, can feed the healthy gut bacteria and encourage their growth. It is safe at any age and stage of life, and is a single ingredient product, which is important when dealing with possible adverse food reactions. It makes a lot of sense to think about using a prebiotic in the prevention of allergic skin disease.