I. What is Atopic Dermatitis?

Atopic dermatitis is also known as allergic inhalant dermatitis, that is, an allergic reaction caused by substances that are inhaled or breathed in. People who have inhalant allergies usually have symptoms affecting the respiratory tract such as runny nose, sneezing, itchy watery eyes and chronic sinusitis or sinus infections. Dogs that have inhalant allergies develop skin symptoms instead of respiratory symptoms.

In dogs that are predisposed to developing atopic dermatitis, exposure to an allergen (substance that the dog is allergic to) leads to the production of a specific type of antibody called IgE. IgE in the skin attaches to cells in the skin called mast cells. These mast cells release substances that can cause inflammation in the skin. This process would normally occur in a dog to help protect it from organisms or molecules that might cause disease. In the dog with atopic dermatitis, this response is exaggerated and the release of substances from mast cells leads to excessive inflammation, itching, and other symptoms of atopic dermatitis.

While it is commonly thought that atopic dermatitis results from inhaling an allergen, it may be possible for a dog to absorb allergens through its skin as well. The tendency to develop allergies and allergic inhalant dermatitis is thought to be inherited. Many dog breeds are predisposed to atopy. Signs of atopic dermatitis usually do not being to develop until a dog is at least one to two years of age. This is because a dog does not develop atopic dermatitis the first time that it is exposed to an allergen. It develops sensitivity to allergens over time and after repeated exposure. This exposure probably occurs during the first couple of years of life.

II. What to Watch for At Home – Symptoms of Atopic Dermatitis

The very first symptom of atopic dermatitis is itching, known as pruritis. At first, itching may only occur during certain seasons (i.e. spring and fall), but as time progresses, it is common for itching to continue year-round. This is because dogs usually develop allergies to other things as time goes on. Initially, itching is most severe on the face, ears, feet, and around the area of the anus. Excessive itching and scratching produces reddened areas of hair loss. In areas where excessive chewing and licking occur, such as the feet, light colored hair may be turned a rusty brown color by saliva.Dogs with atopic dermatitis are also thought to have changes in their immune systems that make them more likely to develop skin and ear infections. These infections are caused by a combination of bacteria and yeast. Signs of a skin infection include circular hairless areas, pustules, bumps, crusts, scabs, and redness. Skin infections by themselves are itchy, so the combination of an allergic reaction and a skin infection will make a dog extremely itchy. If scratching, chewing and skin infections continue for a long time, the skin may become darkened in color (hyperpigmented), thick feeling, and greasy. With ear infections you may see rubbing or pawing at the ears, redness of the ear canal, and discharge coming from the ear.

Dog with Atopic Dermatitis Affecting its Face

Scales and bumps seen with a skin infection

III. The Veterinary Visit – How to Tell if a Dog has Atopic Dermatitis

A diagnosis of atopic dermatitis is usually based on a combination of the history of the symptoms and the physical examination findings. A skin scraping to rule out a mite infestation (mange) and fungal cultures to rule out ringworm infections may be needed, also. For dogs that develop atopic dermatitis when they are older, routine blood work including a thyroid hormone level is necessary to make sure there are no underlying diseases that might be predisposing them to developing dermatitis and skin infections.

Once a diagnosis of atopic dermatitis is reached, there are a couple of tests that can be done which might show specifically what things a dog is allergic to. These are skin testing and blood testing. Both of these are similar to the allergy tests that are done in people. They can provide information which might be used to help avoid the things that a dog is allergic to or to develop a program of allergy injections to desensitize the dog to allergens (hyposensitization).

An Intradermal Skin Test in a Dog

IV. Treatment/Control of Atopic Dermatitic

Atopic dermatitis cannot be cured. The goal of therapy is to provide relief from symptoms. Usually a combination of the methods listed below is used. Each dog responds differently to therapy so a different protocol must be developed for each dog.

• Shampoos and rinses – Anti-itch shampoos and conditioners can provide very short-term relief from symptoms. Antibacterial shampoos are usually used with oral antibiotics as an aid in treating skin infections. Topical therapies alone seldom provide enough activity to control itching or skin infections.


• Antihistamines –Antihistamines are used to control itiching. All dogs respond differently to antihistamines and there are several available for dogs. Several may have to be tried before one is found that is helpful.


• Omega-3 Fatty Acid Supplements – Omega-3 Fatty Acid supplements containing EPA and DHA are thought to be anti-inflammatory and may help control itching in dogs with atopic dermatitis.


• Corticosteroids – Corticosteroids such as prednisone are used to help control itching and also to decrease the immune response that is causing symptoms in the first place. Steroids may be very helpful at controlling symptoms but have many side effects. If corticosteroids are used, it is important to reduce the dose to the smallest possible dose given at the lowest frequency that helps to control symptoms. Combining steroid use with other treatment options helps to achieve this goal.


• Cyclosporine – Cyclosporine is used to decrease the immune response, which is causing the symptoms. It is used instead of corticosteroids. Like corticosteroids, it suppresses the immune system, but at the doses used for atopic dermatitis, it has fewer side effects.


• Antibiotics and Antifungals – Oral antibiotics and antifungal medications are used to treat bacterial and yeast skin infections which are usually present in dogs with atopic dermatitis. Because skin infections also cause itching, it is important to eliminate them. This will help provide relief from symptoms.


• Ear medications – Topical antibacterial and antifungal ear medications may be necessary if a dog has ear infections.


• Allergy Shots (hyposensitization) – Allergy shots are useful in about 65-75% of dogs with atopic dermatitis. They are not necessary for dogs that only have seasonal symptoms or dogs whose symptoms are well controlled with other therapy.

This information is not intended to diagnose or provide treatment for your pet or be a substitute for diagnosis and appropriate treatment by your veterinarian.