title: Allergic contact dermatitis.
abstract: Contact dermatitis is an inflammatory skin condition induced by exposure to an environmental agent. Eczema and dermatitis are used synonymously to denote a polymorphous pattern of skin inflammation characterized at least in its acute phase by erythema, vesiculation and pruritus. Substances responsible for contact dermatitis after single or multiple exposures are non protein chemicals, i.e. haptens, that induce skin inflammation through activation of innate skin immunity (irritant contact dermatitis) or both innate and acquired specific immunity (allergic contact dermatitis). The present review will focus on allergic contact dermatitis, a delayed-type hypersensitivity reaction, which is mediated by hapten-specific T cells. Recent advances in the pathophysiology of ACD have shown that the occurrence of ACD, as well as its magnitude and duration, is controlled by the opposite functions of CD8 effector T cells and CD4 regulatory T cells. From these studies ACD can be considered as a breakdown of cutaneous immune tolerance to haptens.
authors.affiliation: INSERM U 503, IFR 128 Bioscience Lyon-Gerland, 21, avenue Tony Garnier 69007 Lyon.
authors.forename: Pierre
authors.initials: P
authors.lastname: Saint-Mezard
authors.forename: Aurore
authors.initials: A
authors.lastname: Rosieres
authors.forename: Maya
authors.initials: M
authors.lastname: Krasteva
authors.forename: Frédéric
authors.initials: F
authors.lastname: Berard
authors.forename: Bertrand
authors.initials: B
authors.lastname: Dubois
authors.forename: Dominique
authors.initials: D
authors.lastname: Kaiserlian
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Nicolas
mesh_terms: D017449:Dermatitis, Allergic Contact / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy; D006801:Humans