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Allergies: Atopy

Understanding Your Pet's Medical Diagnosis

What is atopy?

Atopy describes an allergic skin reaction; it is a form of hypersensitivity to substances (allergens) that cause allergic responses. It is usually a seasonal disease. Animals living in temperate environments with long allergy seasons may have increased risk of developing atopy. While this disease occurs in dogs and cats, atopy is reported more commonly in certain dog breeds.

What causes atopy?

Susceptible animals become sensitized to substances in the environment. Atopy is caused by environmental allergenssuch as mold spores, animal dander (dead skin cells normally shed from animals), natural fibers, and dust mites. Airborne pollen from trees, weeds, or grass also causes atopy. When the sensitized animal comes in contact with a specific allergen, the animal's immune system overreacts and the animal develops signs of atopy.

What are signs of atopy?

Signs associated with atopy relate to the animal's sensation of itchiness. The animal may lick, bite, or chew the toes or feet, the areas under the front legs, or the groin excessively. The animal also may scratch and rub its muzzle (the mouth, nose, and jaws). Affected animals often have histories of previous bacterial skin infections, ear infections, fleas, or flea allergy. Characteristic skin abnormalities (such as scaling, crusts, redness, hair loss, and rash-like bumps) are seen commonly on the feet and ears. The areas around the eyes and under the front legs and groin also are affected. Cats with atopy frequently scratch at their heads or ears. The hair may be oily and the skin may be thickened in some areas.

How is atopy diagnosed?

Atopy may be diagnosed based on a history of itchiness, the presence of characteristic skin lesions, and characteristic blood test abnormalities. Allergy testing may be done. Allergy testing may involve intradermal skin tests or blood tests. The goal of allergy testing is to identify those substances to which the animal reacts strongly. Once the substances are identified, it may be possible to limit exposure of the animal to the substance or to give the animal allergy shots (immunotherapy) to lower the animal's reaction to the substance (hyposensitization).

How is atopy treated?

The primary treatment of atopy involves avoiding contact with the offending allergen, if possible. Unfortunately, avoiding the allergens in the animal's environment frequently is impossible. The animal may be given allergy shots (immunotherapy) based on results of allergy testing. Immunotherapy successfully reduces itchiness in 60% to 70% of atopic pets. Immunotherapy generally requires months of treatment before a response is seen. Other treatment options, such as steroids and antihistamines, may be used to suppress or reduce the severity of the allergic response. The addition of essential fatty acids to the diet may have beneficial effects on the skin. Recheck examinations should be scheduled regularly to see if the treatment is working. Blood and urine testing should be performed on all animals receiving long-term steroid therapy.

What is the prognosis for animals with atopy?

The prognosis (outcome) for animals with atopy usually is good if medical therapy and appropriate environmental changes have been started. Atopy cannot be cured completely, so some form of therapy may be required for the animal's entire life. If left untreated, the disease will become more severe as the animal ages, and the signs of atopy may persist throughout the entire year.

The information on this page was obtained from the site www.vetmedcenter.com