Atopy is a term used to define the development of skin sensitivity to environmental allergens. These could include pollens (grasses, trees, and weeds), mold spores, house dust mites, and skin dander allergens. Immune proteins specific to the allergen bind to cells in the skin (the mast cells), which when later exposed release molecules including histamine which generate an itch response. The classical areas involved are the skin and the ears; and, ear infections can result secondary to chronic inflammation. It is likely that atopy is a partially inherited disease in dogs, also influenced by environmental factors.
Atopy may account for up to 30% of canine skin disease, and may occur in as much as 15% of the dog population. Although seasonal and environmental factors affect the development and expression of this disease, it accounts for a major proportion of skin disease seen in dogs. While this disease occurs in all breeds of dogs, certain breeds seem to have a higher disposition to atopy. The following breeds have all been reported to have an above average incidence of atopy:
Female dogs are reportedly more commonly affected than males, though it certainly occurs in either sex. In general, the onset of signs is usually around one to two years of age, though the range can be from 3 months to 7 years. Signs usually worsen with ongoing exposure.
The primary symptoms of atopy are itchiness and self-mutilation. Initially the itchiness is usually seasonal, and the classical distribution involves the face, ears, and feet, with licking or scratching at these areas. The armpits or groin may also be involved, and some dogs may sneeze. Recurrent skin and ear infections often occur secondary to the chronic inflammation.
The coat may be excessively oily, and chronically affected animals often have scaling, crusting, and thickening of the skin. The disease occurs most commonly in temperate climates with long allergy seasons due to higher pollen and mold spore levels in these areas. It may be worsened by concurrent flea or dietary allergies. Diagnosis can be assisted by: – skin scrapings to rule out mite and yeast infections, – diet and flea elimination trials, and – skin biopsy to rule out other causes of itchiness.
On the occurrence of the signs, the first step should be taken through the masters for the dogs. The infection should not be converted into a chronic disease. For further information, the Homepage at the official site is opened to know about the benefits and risks involved. The availability of the information will provide effective results to the master of the dog.
More specific determination of the allergens involved may be attempted by the administration of intradermal skin tests in which different allergens are injected into the skin to determine to which ones the dog will react. Intradermal testing is not, however, universally available. Blood testing is also available; in this testing, the specific immune proteins are tested for. Although technology is improving, false positive results can still be a problem in some laboratories.
Treatment requires the pursuit of a number of options, with no one universally effective method. Offending allergens should obviously be avoided as much as possible, although in the case of widespread environmental allergens, this is not always practical. In some cases, the supplementation of the diet with essential fatty acids can be helpful. Antihistamines have been helpful in a percentage of cases, and some evidence suggests that their effect may be enhanced by concurrent fatty acid supplementation.
In some cases, tricyclic antidepressant drugs such as amitriptyline have been used for their antihistaminic effects with some success. Most atopic dogs will respond at least temporarily to the administration of corticosteroid drugs, however, due to the significant long-term side effects of these medications, their use should be minimized. -Desensitization to specific allergens after allergy testing is an excellent option to consider, and may decrease the itchiness and inflammation in 60 – 70% of patients.
The program involves the determination of specific allergens by either skin testing or blood testing, followed by the injection under the skin of gradually increasing amounts of the specific allergens in an attempt to eventually create tolerance to these allergens by the immune system. While this program is an excellent option in the successful cases, the response is slow, often requiring 3 – 6 months, and the procedure can be prohibitively costly for many people.
In summary then, atopy is a multifactorial allergy of dogs, with no one good solution. Once diagnosed, most dogs will require treatment with one or several of a variety of modalities for the rest of their lives. As technology progresses, blood testing for specific allergens may improve, making desensitization a more available option.
