Page 1000 - Veterinary Immunology, 10th Edition

to promote inflammation.
VetBooks.ir pruritus, violent sneezing, dyspnea, mucoid nasal discharge, and
A familial allergic rhinitis characterized by extreme nasal

excessive lacrimation has been observed in cattle. Depending on the

allergen, it may be seasonal. The antigens involved are inhaled and
come from a variety of plant and fungal sources. Diagnosis may be
confirmed by skin testing. Nasal granulomas may form in
chronically affected cattle. These consist of numerous polypoid

nodules, 1 to 4 mm in diameter, situated in the anterior nasal
mucosa. The nodules contain large numbers of mast cells,
eosinophils, and plasma cells.

Atopic Dermatitis

Atopic dermatitis (AD) is a complex, multifactorial syndrome
characterized by chronically inflamed and itchy skin. It is very
common in humans and dogs (as many as 15% are affected) and

has been recognized in cats, horses, and goats. It is not simply an
allergic disease driven by allergen exposure because it also involves
immune dysregulation, skin barrier defects, and microbial
colonization. It is better considered to be a manifestation of multiple
diseases, mainly driven by Th2/Th22 responses with some

contributions from Th17 and Th1 cells.
Transcriptome profiles of the blood lymphocytes in dogs with
AD showed increases in CD8+ and Treg cells Likewise, there is

increased expression of IL-13 and tumor necrosis factor-α, as well
as decreased expression of IL-10 and TGF-β. The increase in Tregs
together with a decline in IL-10 and TGF-β suggests that Treg
function is somehow impaired.
Some forms of AD are due to IgE-mediated allergic responses to

environmental allergens and so can be classified as extrinsic AD.
Conversely, other cases are not due to IgE responses and are
classified as intrinsic AD or “atopic-like” dermatitis. Extrinsic AD

cases develop high serum IgE levels, and this IgE is directed against
environmental and food allergens. Intrinsic IgE cases have normal
IgE levels.

Clinical Disease

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