University of California, Davis
Veterinary Medical Teaching Hospital
Davis, CA 95616
Small Animal Clinic: 530-752-1393
Dermatology Service
Information for Clients
ATOPIC DERMATITIS
Introduction
Atopic dermatitis is the name given to the itchy skin reaction dogs and cats can
have to environmental allergies. This includes allergies to pollens, mold spores, danders,
dust, and dust mites. In animals, these allergic substances (known as “allergens”) can be
inhaled or absorbed through the skin from the environment. Unlike human “hay fever”
animals only rarely have runny eyes/nose or other respiratory signs. Instead, animals are
itchy and develop red, irritated skin and ears. The allergic reaction can persist for months
and often begins slowly and gets worse over time. Like human “hay fever,” atopic
dermatitis is a heritable disease and is therefore seen more in certain breeds of dogs.
Labrador and Golden Retrievers, German Shepherd Dogs, Chinese Shar Peis, Shih Tzus
and many Terrier breeds are among the most affected breeds. Certain breeds of cats are
also more predisposed, including Himalayans, Persians and Abyssinians, Atopic
dermatitis in animals is a progressive disease, which typically worsens with each year of
life as the pet is exposed over and over again to the offending allergens. Usually, animals
are allergic to a combination of allergens, and changing the environment is not
particularly helpful. Allergies cannot be cured, but often can be well controlled.
Clinical Signs
Pets with atopic dermatitis will be pruritic (itchy) over their feet, front legs, face,
ventral neck, “armpit” area and abdominal area. The affected areas may include any or
all of the above, or can include the entire body. Initially, many atopic animals will have
seasonal itchiness, which, often, as the disease progresses, becomes year round. Red,
itchy or painful ears and recurrent ear infections are also common for dogs with atopic
dermatitis.. Because affected animals are reacting to allergens in the environment ,and
these may change over time, the clinical signs may wax and wane daily. Secondary skin
infections are very common, can recur often and must be treated as a part of any
management plan.
Diagnosis
Because the itchy skin of atopic dermatitis mimics other itchy skin diseases, the
diagnosis is made by excluding all other possible causes of itchy skin. Once external
parasites, secondary skin infections and food allergy have been ruled out, atopic
dermatitis is the most likely diagnosis. Other suggestive information that a patient has
atopic dermatitis include the distribution of the itchiness on the animal’s body
seasonality, and response to certain medications. Allergy testing followed by
hyposensitization immunotherapy (allergy ‘shots’ or ‘drops’) may be indicated. Allergy
testing can be performed two ways: Intradermal (skin) testing is the traditional testing
method, and more recently blood tests for environmental allergens have been developed.
Treatment
Treatment for atopic dermatitis can be varied and multilayered. Unfortunately,
not all animals respond to all treatments; therefore, usually a combination of treatments
and medications are needed to control the condition. Treatments may include topical
shampoos and rinses to help control itching and secondary infections, oral cortisone
products, oral antihistamines and fatty acid supplementation. Allergy testing followed by
hyposensitization immunotherapy (allergy ‘shots’ or ‘drops’) may also be used. Based
on results from allergy testing, allergy serum for hyposensitization injections or oral
administration can be made. Allergy injections are initially given every 48 hours for one
month, then the frequency is reduced to once weekly. Allergy drops are administered
twice daily, continually. We can train you how to give which ever method you choose.
Hyposensitization immunotherapy has about a 75% success rate, but can take 9-12
months to show results. Your pet may require one or several treatments to control the
itching due to atopic dermatitis. Additionally, any secondary skin infections will need to
be treated, as they are also itchy, and will greatly aggravate the skin condition.
Other options include an oral drug called cyclosporine (Atopica®). While
generally safe, it does require occasional laboratory test monitoring for safety, and the
drug itself is reasonably expensive. Another medication which is generally safe and
effective, but is on national back-order, is oclacitinib (Apoquel®)
Any secondary bacterial or yeast skin infections must also be treated with the
appropriate medications, as these can contribute to the pet’s sensation of itch.
Prognosis
Atopic dermatitis is a progressive disease that is not cured, but when successfully
managed pets can live comfortably with their allergies. . Because of its progressive
nature, control of the clinical signs can sometimes be frustrating. Relapses are common,
and treatment protocols may need to be modified fairly frequently. However, with
consistent treatment and careful follow-up, the majority of pets with atopic dermatitis can
live long, comfortable lives!