Irritant effects of a detergent in wash and chamber tests

Irritant properties of detergents can be tested by using patch and chamber tests and various kinds of use tests. The aim of the present study was to compare the results of use and 12 mm Finn Chamber tests. Study subjects (10 atopic and 11 non-atopic medical students) washed the outer aspect of 1 upper arm with liquid detergent for 1 minute 2 x daily for 1 week. 48-h chamber test with 5 concentrations of the same detergent in water were concurrently applied to upper back skin. Transepidermal water loss (TEWL), electrical capacitance and skin blood flow were measured to quantify reactions on days 0, 2, 5 and 7. Irritant contact dermatitis developed equally in atopics and non-atopics in the wash test, whereas in the chamber test with a 10% aq. solution of the detergent, increase in TEWL was significantly higher in atopics than in non-atopics. The chamber test results thus predicted poorly the result of the wash test. This might indicate that the wash test and the chamber test measure different aspects of skin barrier function.