How antibodies and allergens affect dog atopic dermatitis

Abstract

BackgroundCanine atopic dermatitis (AD) is considered to be an immunoglobulin E (IgE)‐mediated hypersensitivity response to environmental allergens. The role of other antibody isotypes and nonenvironmental allergens in disease pathogenesis remains unclear.ObjectivesThe objective of this review is to provide an update on advances in the understanding of the relevance of specific antibody isotypes, autoallergens and nonenvironmental allergens in the pathogenesis of canineAD.MethodsCitation databases, abstracts and proceedings from international meetings published between 2001 and 2013 were reviewed. Where necessary, older articles were included for background information.ResultsNeither total nor allergen‐specific IgE necessarily correlates with clinical disease in canineAD. Some dogs exhibit clinical signs that are indistinguishable fromADbut have no demonstrable allergen‐specific IgE (atopic‐like dermatitis). Allergen‐specific immunoglobulin G may be demonstrated in canineAD, but there is no evidence that this isotype plays a role in disease development. Although humans withADmay develop serum IgE against autoallergens, this finding has not been substantiated in the dog. In contrast, adverse food reactions are frequently co‐associated withADin the dog. Ingestion of food and environmental allergens may trigger exacerbations ofAD.Conclusions and clinical importanceDetermination of the role of IgE in the pathogenesis of canineADstill requires clarification. Clinical trials and research studies must distinguish atopic dogs with allergen‐specific IgE or skin test reactivity from those without. There is no convincing evidence demonstrating a pathogenic role for either allergen‐specific immunoglobulin G or autoallergens in canineAD, but food items may be triggers for disease flares in certain individuals.