Irritant contact dermatitis. Traumiterative and cumulative impairment by cosmetics, climate, and other daily loads.

Based on the results of exposure experiments on living human skin a working hypothesis is launched concerning the possible pathogenesis of irritant contact dermatitis. Below a certain and critical degree of exposure there is no alteration in clinical aspect of the exposed region. However, instrumentally (watervapour-loss measurements, impedance measurements) it is usually possible to register subclinical effects in such a field. These are interpreted as signs of impairment of metabolic homoiostatic systems. It is possible in certain cases to show that the skin is able to adapt its functions to a repeated load (illustrated with exposure experiments to DMSO). It seems useful to distinguish between a traumiterative irritant contact dermatitis (a result of too early repetition of just one type of load; see Aquabrom experiment) and a cumulative irritant contact dermatitis (resulting from a too early repetition of exposures differing in type; see experiment with soap and detergent solutions). In cumulative irritant contact dermatitis the sequence of the different loading factors is of importance: first soap and then detergent or the reverse.