Protection from combination exposure.

In the workplace, repeated skin exposure to a combination of irritants either simultaneously or one after the other is frequent. Therefore, assessing the efficacy of skin protection products only against single irritants is far from the daily life situation. We studied the interaction of irritants in a tandem repeated irritation test (TRIT). Shortly, healthy volunteers are exposed repeatedly to different irritants, and the skin reactions are assessed by visual scoring, transepidermal water loss, chromametry and skin capacitance. Using this model, a potentiation of irritation could be shown for several combinations of irritants, such as sodium lauryl sulfate (SLS) and toluene, SLS and mechanical stress, and SLS and hot airflow. The TRIT has been successfully used to prove the efficacy of a protective cream against a tandem application of 0.5% SLS and undiluted toluene. This test has great potential for the evaluation of skin care products to prevent irritant contact dermatitis.