Atopic dermatitis, allergic disorder

PIH can be observed after endogenous or exogenous inflammatory conditions. Essentially any disease with cutaneous inflammation can potentially result in PIH in individuals capable of producing melanin. Several skin disorders such as acne, atopic dermatitis, allergic contact dermatitis, incontinenti pigmenti, lichen planus, lupus erythematosus, and morphea have PIH as a predominant feature. Exogenous stimuli,both... 

It is indicated in bronchial asthma, migraine, urticaria, eczema, allergic rhinitis, pruritus, neurodermatitis, atopic dermatitis and other allergic disorders. 

These tests are mainly used for the research purposes. Atopic dermatitis and allergic eosinophilic gastroenteritis are examples for disorders with mixed mechanisms, in which both IgE antibody and cell immunity may play a role (Sampson, 2004). 

Allergic disorders of the eyelid include atopic dermatitis, contact dermatitis, and urticaria. Eczema is a common feature of both atopic and contact dermatitis.Table 27-5 summarizes the clinical manifestations and management of each entity. 

The link between SEs and allergic disorders is most firmly established for atopic dermatitis (AD) (reviewed in Leung [10] and Breuer et al. [11]). AD affects 10-15% of the population, but S. aureus colonization is observed in the skin lesions of >90% of AD patients, compared with 5% of normal skin [12], Moreover, the intensity of skin inflammation has been correlated with the degree of S. aureus colonization [13]. Most strains of S. aureus grown from atopic skin have been shown to produce SEs with superantigenic properties [14], In accordance with the view that the SEs induce or exacerbate AD, treatment of AD patients with steroids in combination with antibiotics is more effective than treatment with steroids alone [15, 16]. 

It is generally believed that these four canonical mechanisms of IgE-mediated activation of human FceRI + cells are responsible for the pathophysiologic involvement of these cells in allergic disorders [7], However, a significant percentage of allergic diseases (e.g. certain cases of asthma, chronic idiopathic urticaria, and atopic dermatitis) cannot be explained by the four classical mechanisms of FceRI + cell activation. 

This chapter will review our current knowledge about the pathogenesis of allergic skin disorders, in particular atopic dermatitis (AD) and urticaria. Anti-lgE therapy has not been systematically studied in these skin diseases. Therefore we will discuss the role of IgE in their pathogenesis and provide a scientific rationale for use of anti-IgE treatment in these diseases. Recent studies indicate that the IgE molecule has a multifunctional role in these diseases, acting as both a target and a key player in the elicitation of allergen-induced immediate hypersensitivity reactions and cell-mediated responses. 

The duality of Thl and Th2 T-helper cells that exists in murine animals probably also exists in humans (14). It has been postulated that IL-4 enhancement promotes the development of IgE-mediated hypersensitivity disorders such as food allergy, while the combination of defective INF-y with enhanced IL-4 production promotes inflammatory atopic disorders such as atopic dermatitis and asthma. IgE irmnunoregulation suggests that the magnitude of the IgE response to persistent allergens depend upon this balance between T-helper cells and their cytokine production. However, environmental and other as yet unidentified factors also contribute to the allergic state of the predisposed individual. 

Atopic dermatitis (AD) is a chronic disorder that begins in children characterized by extreme pruritis, a chronically relapsing course, and an association with asthma and allergic rhinitis. Approximately one-third of children who have atopic dermatitis has a food allergic reaction. In food challenges, skin symptoms that are provoked include a pruritic, erythematous, morbiliform rash that develops in sites with a predilection for atopic dermatitis. Urticarial lesions are not uncom-... 

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