Issue Description Atopy is a common cause of chronic itching in
dogs. (It is believed to affect 15% of dogs in North America.) Dogs
that have atopy usually itch and so scratch a lot, which can cause
red, moist, irritated skin. The face and feet are most commonly
affected but ear infections are also common. Sometimes, dogs with
atopy will also have runny eyes or nose. Other Names Allergic Dermatitis, Canine Atopic Dermatitis, Allergic Inhalant Dermatitis
Causes The most common allergens include airborne
pollens such as grasses, trees, weeds, and fungal spores. Indoor
allergens include natural fibers such as wool and household dust
mites. In addition, some animals are allergic to the dander from other
animals in the same dwelling. It commonly starts between the ages of
one and five years.
Breeds Commonly Affected
Pug, Scottish Terrier
West Highland White Terrier
Wire-Haired Fox Terrier.
Symptoms Atopy is usually first seen when your pet is
between 1-3 years of age, although it can develop as late as 6-7 years
of age. Initially, symptoms may be seasonal, but usually progress to
being present year-round with time.
The primary symptom of
atopy is itchiness. Your dog may scratch, lick, chew, or rub along the
carpet. The face, paws, lower legs, and groin are the most commonly
affected areas, followed by the ears and eyes. Initially, you may see
slight reddening of the affected skin areas. Eventually, these areas
are likely to develop more severe lesions and may become abraded,
thickened and wrinkled in appearance. The area may also become darker
in color (hyperpigmentation) or stained from constant licking (saliva
stains). You are likely to notice hair loss as well.
Diagnosis The veterinarian will ask the owner about the
animal's history of symptoms. During the physical examination, the
presence of itching and skin lesions will be assessed. Before
concluding a diagnosis of inhalant allergy, the veterinarian will need
to rule out other skin diseases including food hypersensitivity, flea
allergy dermatitis, sarcoptic mange, contact dermatitis, and yeast
infection of the skin. Diagnostic procedures can include bloodwork and
urinalysis, and skin scrapings, and fungal cultures. Intradermal skin
testing is believed to be the most accurate of the allergy tests; this
procedure should be performed by an experienced veterinarian or by a
veterinary dermatologist. There are also blood tests which may provide
information about inhalant allergies for canines.
Treatment Treatment involves the avoidance of identified
allergens when possible. Essential fatty acid supplements, given at
higher doses, can help control the symptoms. Medications can include
antihistamines, corticosteroids, and immunotherapy, or allergy shots.
Owners should be aware that long-term use of corticosteroids can
result in complications including iatrogenic Cushing's disease, or
excessive levels of glucocorticoids in the body, diabetes mellitus,
and worsening bacterial or fungal skin infections. Allergy shots are
formulated specifically for individual animals and are administered by
an injection under the skin. Improvement of symptoms can take three to
twelve months. Immunotherapy is successful in reducing itching in 60
to 70 percent of dogs and 73 percent of cats. In addition, shampoos
and topical products may be beneficial.
Prognosis Inhalant allergy is a life-long disease that
tends to worsen with age. Therefore, treatment is required for the
duration of the animal's life.
Prevention Prevention includes avoiding known allergens by
maintaining a dust-free house, closing windows, and keeping the animal
indoors during high pollen season. It is also important to minimize
complicating factors such as fleas, a dirty haircoat, and skin or ear
infections. Because the predisposition to inhalant allergies may be
genetically transmitted, affected animals should ideally not be bred.