The vet’s office: Allergic skin disease in dogs and cats
By Dr. Elizabeth Knabe, DVM
Wildwood Animal Hospital and Clinic LLC
Atopy is the inherited tendency to develop antibodies against things in the environment. Pollens, molds, dander, food, fleas, and mites can all be the triggers for development of allergies. Though the predisposition for allergies is inherited, the specific form the allergy takes is not.
Some pets, just like some people, have different forms of allergic responses. The most common type of allergic response seen in pets takes the form of skin reactions, but respiratory and intestinal tract problems can occur as well.
Just like in people, it takes a pet’s immune system some time to react from first exposure to an allergen such as pollen. This is why allergies might not appear until a pet is 4 years old, though it could come as early as 6 months of age.
The antibodies react with offending allergens such as pollen and set off a cascade of inflammatory chemicals that are released into the skin or other tissues. One important compound is histamine, which stimulates the redness, swelling, and itch of an allergy. Since cats and dogs have more histamine available in the skin, that is where their reactions tend to be.
Histamine is necessary to the body to start the healing process after tissue trauma or to help fight infections. The sustained elevation of histamine in allergic reactions is the problem.
New research shows the skin barrier itself is also an important consideration in atopy. A normal pet’s skin keeps out the allergens. A dysfunctional skin barrier of an allergic pet allows penetration of allergens as well as microbes plus their toxins.
These infections and toxins further weaken the skin barrier and set up a vicious cycle of inflammation and itching. Skin is full of tiny nerve endings, and compounds released during allergies interact with nerves to send sensations of constant itchiness.
An approach to allergic skin disease first involves a search for the diagnosis. There are various skin and blood tests that look at levels of antibodies for the allergens. They are the gold standard tests, but they can give mixed results and are not always conclusive.
If your veterinarian has a high index of suspicion for allergies and other conditions are not found, a diagnosis of allergy may be made. Your veterinarian will then formulate a treatment plan — often including topicals plus medications — to fight itchiness, secondary infections, and the release of the pro-inflammatory compounds.
Wildwood Animal Hospital and Clinic LLC is located at 210 Airpark Road in Marshfield and online at wildwoodanimalhospital.net.