Pets And People: Itchy Skin in Dogs (Atopy)


One of the most common diagnoses I have to make is atopy in dogs.  Everyone knows someone with hay fever.  Airborne pollens, molds, dust particles, etc. are inhaled and soon the sneezing and sniffling begins.  A simple way to think of atopy for pets would be saying that the airborne allergen is inhaled by the pet but instead of sneezing and sniffling, the pet gets itchy skin. In fact, this was what we thought was happening for many years, but the situation turns out more complicated.

In atopic dermatitis, airborne pollens, molds, dust particles etc. gain entry to the skin through a defective skin barrier.  Inhaling is not involved.  The immune system becomes inflamed by the airborne allergens and soon the itching and scratching begins. The allergens come from the air, but the itch is felt in the skin.

There are many reasons for pets to itch: parasites, allergy to flea bites, food allergy, secondary infection and the list goes on.

Seasonal itchiness due to atopy tends to begin early in a pet's life (between ages one and three years in 70 percent of dogs diagnosed with atopy).  Food allergy tends to begin later (more like age five or six years in dogs) or earlier (less than six months of age).

Treatments include:  Hyposensitization, more commonly known as allergy shots, is by far the treatment of choice for atopic dermatitis.  All the other medications are basically just itch relief; only hyposensitization actually changes the immune system.  Some dogs are eventually able to go off all treatment and are no longer allergic after they have been on hyposensitization long enough.  Most dogs experience at least enough improvement to require fewer additional treatments but there are some caveats before making an appointment for allergy testing.

Allergy shots require approximately six to 12 months to begin working.

Twenty five percent of atopic dogs will not respond (these are usually the animals allergic to multiple allergens).

Twenty five percent will require prednisone or similar steroid at least at some times.

You will most likely have to give the allergy shots yourself.

Referral to a veterinary dermatologist may be necessary.

Steroid Hormones: These cortisone-type medications (prednisone, prednisolone, triamcinolone, dexamethasone, etc.) have been useful as the first line of defense against itchy skin for decades, and they are still widely used.  There are negative side effects with higher doses as well as with long-term use, so the trend is to use other medications to either remove the need for steroids or reduce the amount needed for itch control.   Steroid hormones are useful for acute flare-ups as well as for long-term management of atopic dermatitis (assuming limits are placed on how long they are used).  Side effects are greatly minimized when steroids are used topically.

Oclacitinib (Apoquel): This is a new medication best used for itching relief and blocking itch symptoms.  Apoquel is popular as it works fast.  It does not address the inflammation in the skin; it just stops the itch sensation.  This means that any skin infection causing the itch will still need to be controlled. 

Canine Atopic Dermatitis Immunotherapeutic (Cytopoint) Injections

This is a new treatment that uses vaccine technology to eliminate one of the main mediators of itch sensation.  The injections provide relief from itching for one month in 80 percent of dogs (many dogs get longer relief) and usually show effectiveness within 24 hours.

Bathing the pet weekly to remove allergens from the fur may be helpful in reducing allergen exposure, plus tepid water is soothing to itchy skin.  There are also many therapeutic moisturizing shampoos that can be used to restore the skin’s natural barrier or to assist in general itch relief

Avoid stuffed toys, wash bedding regularly.  This minimizes dust mite exposure. Also, remove the pet from the area when vacuuming or dusting.

Use air-conditioning and/or an air filter system.

Keep the pet away from the lawn while it is being mowed.

Minimize houseplants.

Omega 3 Fatty Acid Supplements: These products are not analogous to adding dietary oil to the pet's food, such as olive oil, coconut oil, corn oil etc.  Instead, these special fatty acids act as medications, disrupting the production of inflammatory chemicals within the skin.  By using these supplements, it may be possible to postpone the need for steroids/cortisones or reduce the dose of steroid needed to control symptoms.  It takes a good six weeks to build up enough Omega 3 fatty acids in the body to see a difference.

Itchy skin has been the scourge of dogs, cats and their owners for decades, if not centuries.  We are now armed with a great understanding of immunology and have many tools to address allergy symptoms.  Your veterinarian can guide you further with regard to a proper regimen.  If your veterinarian decides treatment is not working as well as hoped, discuss whether or not a referral to a veterinary dermatologist is in your pet’s best interest

Dr. Lamb is the Veterinarian at the Manchester Animal Hospital.