Atopic dermatitis is an allergic disease syndrome in which exposure to environmental allergens leads to an overzealous immune system response. This results in itchy skin and ears, which dogs and cats will demonstrate by scratching, licking, rubbing, and biting at themselves. As we talked about in the previous blog entry, common allergic triggers in the environment include dust, dust mites, pollens, environmental molds, and insects. Symptoms of atopic dermatitis may be year round or seasonal, depending on the individual animal’s allergic triggers.
Arriving at the diagnosis of atopic dermatitis can be a long process because it is a diagnosis of exclusion. This means we come to the diagnosis of atopic dermatitis by first ruling out all other causes of itchy skin disease. Many times we do not arrive at the diagnosis until your pet has first undergone a 6-8 week strict elimination diet trial to rule out food allergies, a parasite treatment trial, and/or treatment of yeast or bacterial skin infections.
“Why can’t you just allergy test my pet so we don’t have to go through a diet trial?”
This is something we hear a lot! Allergy testing can be very valuable, but it is not used for initial diagnosis of allergies. For one thing, food allergy tests are notoriously unreliable and test results often do not correlate with a patient’s clinical response to foods. Our dermatologists do not recommend food allergy testing. Allergy testing for environmental allergies is something we perform frequently, but only after we have already come to the diagnosis of atopic dermatitis (see above). The test should not be used as an initial diagnostic tool because as with any test, allergy tests may occasionally come back with false positive or false negative results. For example, if you performed the test for environmental allergies on a group of pets with only food allergies (or even a group of pets with no allergies at all), a few of these pets would probably test positive for some environmental triggers. The appropriate use of allergy test results is in creating allergen sera for immunotherapy (aka desensitization therapy).
Atopic dermatitis is a condition that is treatable, but not considered curable. Pets with allergies will likely need some sort of allergy treatment regimen for the rest of their lives. Mild allergy symptoms can sometimes be managed with antihistamines, topical therapies, and supplements. There are currently four treatment options for pets with moderate to severe atopic dermatitis: long-term steroids such as prednisone, a medication called Atopica (cyclosporine, Novartis), a medication called Apoquel (oclacitinib, Zoetis), and desensitization immunotherapy. Each treatment option has certain benefits and drawbacks- there is no perfect treatment option.
Long-term steroid therapy is the least ideal option. This treatment option should be considered an option of last resort- to be used when other treatments have failed. When used long-term, steroid medications have the potential to cause detrimental side effects, and may even shorten the lifespan of your pet. Atopica is a non-steroid medication that is very effective in the treatment of atopic dermatitis. It has been approved for use in the treatment of atopic dermatitis in veterinary medicine since 2003. Apoquel is a brand new medication with promising initial results. This medication was approved for the treatment of allergic skin disease in dogs in 2013, and was released for clinical use in 2014. Soon after release, Apoquel unfortunately went on manufacturer backorder. The backorder is expected to be lifted sometime in 2015. The main limitation of Apoquel so far is that we have limited long-term safety data and limited experience with the medication (since it is such a new medication). Immunotherapy, or desensitization therapy is the only non-drug treatment option that has been shown to produce significant improvement in clinical symptoms of atopic dermatitis. Immunotherapy involves administration of tiny amounts of allergens in attempt to change the way the immune system responds to these allergic triggers. Allergens can be administered by injection (allergy shots) or they can be administered under the tongue (sublingual immunotherapy- SLIT). Each pet’s immunotherapy serum is unique, and is created based on the results of the pet’s allergy test.
Although diagnosis and treatment of atopic dermatitis can be time consuming and complicated, most pets can be managed successfully. Our goals in treating atopic dermatitis are to reduce the severity and frequency of allergic flare-ups and to help your pet live a happy, comfortable life. When your pet is diagnosed with atopic dermatitis, the dermatologists at ADA will discuss the details of the treatment options with you and help you choose the best management plan for your pet.