Canine Atopic Dermatitis (AD)
From Hills Symposium on Dermatology Atopic Dermatitis:A New Paradigm 2006 Rosanna Marsella, DVM,DACVD.
Cause:
Symptoms:
Diagnosis:
Treatment:http://www.labbies.com/atopy.htm
Dogs can develop symptoms of allergy suddenly at any age but it usually occurs in young dogs. Symptoms involve inflammation and persistent itching of the skin, usually in specific locations that are classic for dogs afflicted with dermatitis. Historically, canine Atopic Dermatitis (AD) was defined as a "Type I hypersensitivity" against environmental allergens. This is an allergic reaction provoked by re-exposure to a specific type of antigen referred to as an allergen. This exposure may occur with eating food containing the allergen, breathing it in via the respiratory tract, or direct contact with the allergen. For decades, most of the research effort was devoted to the role of IgE, both in diagnostic testing and monitoring of clinical severity. The role of IgE, however, is considered controversial. Most dogs with canine AD have allergen-specific IgE detectable either by intradermal skin testing or by the use of serological assays such as the enzyme-linked immunosorbent assay (ELISA) [Ref footnotes.3,4] Some normal animals, however, exhibit detectable circulating IgE, are exposed to allergen, but suffer no disease.[Ref footnote 5] Conversely, dogs presented with classical clinical signs of AD may exhibit negative intradermal test and/or negative allergen-specific IgE serology, a situation that is similar to that of intrinsic AD in humans.[Ref footnote 6,7] Importantly, antihistamines appear to have limited clinical efficacy [Ref footnotes 8,9] and clinical lesions are rarely suggestive of a typical type I hypersensitivity (e.g., urticaria and angioedema). Therefore, it is clear that the association between IgE and clinical disease, although important in some patients, is not absolute and additional factors play an important role in the clinical manifestation of the disease.The American College of Veterinary Dermatology task force on canine AD has focused more on the clinical features of the condition than the presence of a type I hypersensitivity to formulate the latest definition for this disease. The definition states that canine AD is a genetically predisposed, inflammatory, and pruritic allergic skin disease with characteristic clinical features most commonly (but not necessarily) associated with IgE antibodies against environmental allergens.(Ref footnote 10)
Cause:
Symptoms:
Diagnosis:
Treatment:http://www.labbies.com/atopy.htm
Dogs can develop symptoms of allergy suddenly at any age but it usually occurs in young dogs. Symptoms involve inflammation and persistent itching of the skin, usually in specific locations that are classic for dogs afflicted with dermatitis. Historically, canine Atopic Dermatitis (AD) was defined as a "Type I hypersensitivity" against environmental allergens. This is an allergic reaction provoked by re-exposure to a specific type of antigen referred to as an allergen. This exposure may occur with eating food containing the allergen, breathing it in via the respiratory tract, or direct contact with the allergen. For decades, most of the research effort was devoted to the role of IgE, both in diagnostic testing and monitoring of clinical severity. The role of IgE, however, is considered controversial. Most dogs with canine AD have allergen-specific IgE detectable either by intradermal skin testing or by the use of serological assays such as the enzyme-linked immunosorbent assay (ELISA) [Ref footnotes.3,4] Some normal animals, however, exhibit detectable circulating IgE, are exposed to allergen, but suffer no disease.[Ref footnote 5] Conversely, dogs presented with classical clinical signs of AD may exhibit negative intradermal test and/or negative allergen-specific IgE serology, a situation that is similar to that of intrinsic AD in humans.[Ref footnote 6,7] Importantly, antihistamines appear to have limited clinical efficacy [Ref footnotes 8,9] and clinical lesions are rarely suggestive of a typical type I hypersensitivity (e.g., urticaria and angioedema). Therefore, it is clear that the association between IgE and clinical disease, although important in some patients, is not absolute and additional factors play an important role in the clinical manifestation of the disease.The American College of Veterinary Dermatology task force on canine AD has focused more on the clinical features of the condition than the presence of a type I hypersensitivity to formulate the latest definition for this disease. The definition states that canine AD is a genetically predisposed, inflammatory, and pruritic allergic skin disease with characteristic clinical features most commonly (but not necessarily) associated with IgE antibodies against environmental allergens.(Ref footnote 10)