THE MODULATION OF SKIN IRRITATION

Irritant contact dermatitis (ICD) is a multifactorial disease, the ons et and modulation of which depend on both endogenous and exogenous fac tors. Among the former, age, race, site, sex and history of dermatitis may all be important. Such variables can now readily be quantified by objective noninvasive techniques, such as measurement of transepiderm al water loss (TEWL). Moreover, effects of irritants on the epidermis are related to the particular chemical properties of each molecule, co ntributing further to clinical heterogeneity. Release of cytokines and mediators may be initiated by a number of cells, including living ker atinocytes and those of the stratum corneum, thus modulating inflammat ion and repair. Furthermore, differences in mechanisms of inflammation between acute and chronic ICD may exist, the former being characteriz ed predominantly by inflammation, the latter by hyperproliferation and transient hyperkeratosis. These findings may explain the complexity a nd difficulty of investigating ICD. Better understanding and quantific ation of these mechanisms may lead to identification of high-risk indi viduals and more effective prevention and treatment.