Irritant potential of different washing procedures used for heavy-duty soiling: Short and intense or longer and mild?

Background: To prevent irritant contact eczema even in occupational fields with heavy-duty soiling, it is generally recommended to use 'mild' hand cleansers (mild detergent without grits, MC). On the other hand, since grit-containing cleansers (GC) show a higher washing power that minimizes washing time, their usage is generally preferred in specific occupational fields.

Objectives: To compare whether a shorter, intense washing period might cause less skin damage than a longer washing period with an MC.

Methods: Differences in cleaning time were first verified in a pilot study using standardized model dirt. In the main study, the forearms of 35 healthy volunteers were washed with three standardized procedures over a period of 3 days, either using 2 min of MC with/without hand brush or 1-min GC. Clinical scoring, transepidermal water loss (TEWL), corneometry, colourimetry and scaliness/roughness (Visioscan) were used to evaluate the epidermal barrier, topography and irritation.

Results: The pre-study showed that washing time doubled when using MC vs. GC. Using GC resulted in stronger barrier disruption, even after a shorter washing period - median ΔT4-T1 TEWL 0.96 g/m /h vs. 4.91 g/m /h respectively, p < 0.0001. The most harmful procedure for the skin was the additional application of a hand brush (18.86 g/m /h).

Conclusions: Short-time washing with GC damages the skin barrier more significantly in comparison to a longer application of an MC. When washing with MC, the strongest irritant reaction occurred when accompanied with hand brushing.