Irritant effects of a detergent in wash, chamber and repeated open application tests

Development of irritant contact reactions in a wash test, in a repeated open application test (ROAT) and in chamber tests were compared with each other in 14 atopic and 14 non-atopic Caucasian medical students. In the wash test, the students washed their upper arm skin with 10% dishwashing liquid for 1 min 2 x a day for 1 week. In the ROAT, they applied the same detergent solution to 1 antecubital fossa 2 x daily for 1 week. Chamber tests were performed with the same detergent using 8 mm, 12 mm and 18 mm Finn Chambers applied to the upper back skin for 48 h. Additional 4 h and 24 h occlusion times were used with the 12 mm Finn Chambers. Test results were evaluated on days 0, 2, 4 and 7 by eye and by using an Evaporimeter EP1 for transepidermal water loss and a Minolta Chroma Meter CR-200 for skin colour. No statistically significant differences between atopics and non-atopics were found in any of the tests. The results of the tests did not correlate with each other, with the exception of the 12 mm/48 h chamber test and the wash test in atopics (R = 0.61, p = 0.02). It seems that other individual factors in addition to atopy influence the development of irritant contact dermatitis. The results of the chamber test and ROAT predicted poorly the result of the wash test.