**Part 2**

**Pathogenesis** 

20 Contact Dermatitis

Yngveson M, Svensson A, Johannisson A, Isacsson A (2000). Hand dermatosis in upper

No.3 (March 2000), pp. 485–489, ISSN 0007-0963

ISSN 0031-4005

children, and adolescents. *Pediatrics,* Vol.78, No.6 (December 1986), pp. 1070–1074,

secondary school pupils: 2-year comparison and follow-up. *Br J Dermatol,* Vol.142,

**2** 

*France* 

**Animal Models of Contact Dermatitis** 

*INSERM U1012, Université Paris-SUD, UMR-S1012, Le Kremlin-Bicêtre* 

Contact dermatitis is an inflammatory disease of the skin resulting from direct contact with foreign substances. Understanding the immunological processes that cause the disease is

Murine models of chemically induced dermatitis have played an essential role in our understanding of the pathophysiology of contact dermatitis, unraveling the role played by inflammatory mediators and identifying potential targets for therapeutic interventions.

In the present chapter we review data obtained in animal models of allergic and irritant

A major intent of this chapter is to highlight the respective role of innate and adaptive immune cells in contact dermatitis pathogenesis as revealed by murine studies. Through genetic ablation of single molecules or depletion of specific cell subsets, murine studies provide novel insight on the role of different components of the immune system in the development of contact dermatitis. We review the experimental evidence revealing the role of different T cell subsets in contact dermatitis development, focusing our attention on mechanisms responsible for maintenance or disruption of immune-tolerance. Our analyses will focus on molecular pathways which are promising candidates as targets of future

Most of our knowledge on the pathophysiology of contact dermatitis is derived from murine models of Allergic Contact Dermatitis (ACD), a T cell mediated delayed-type hypersensitivity reaction also referred to as contact hypersensitivity (CHS). In this model, skin inflammation is induced by topical application on the epidermis of sensitizing chemical

Haptens can be defined as low molecular weight chemicals which are not immunogenic by themselves and that generate new antigenic determinants by binding to epidermal proteins. The reactive haptens commonly employed for ACD induction in murine models include oxazolone (OX), dinitrochlorobenzene (DNCB), dinitrofluorobenzene (DNFB), trinitrochlorobenzene (TNCB), picryl chloride (PI), and fluorescein isothiocyanate (FITC). Such widely employed haptens are all strong contact allergens exhibiting high proinflammatory capacities which therefore differ from the vast majority of chemicals

contact dermatitis and provide basic protocols to reliably induce contact dermatitis.

therefore essential for the development of new therapeutic strategies.

**1. Introduction** 

biological therapies.

**2. Allergic contact dermatitis** 

agents which act as haptens (Eisen et al., 1952).

Federico Simonetta and Christine Bourgeois
