Although the induction of acute
irritant dermatitis by
detergents has been studied extensively in recent years, our understanding of the cell
biological events in the repair phase, and its relevance for the development of chronic
irritant dermatitis is limited. Here we studied the reaction pattern of human skin to short-term application of
sodium dodecyl sulphate (SDS) in a model that induced a minimal acute inflammatory reaction (absence of polymorphonuclear leucocytes, PMN) and did not have cytopathic effects on the epidermal keratinocytes as determined by histological investigation. All parameters were measured up to 14 days after exposure to SDS. Application of SDS caused disturbances of barrier function as measured by transepidermal water loss and had vascular effects as judged by
erythema. Several cell
biological markers for epidermal growth and differentiation were examined by immunohistochemistry. A rapid and strong induction of the cornified envelope precursor
protein involucrin was seen in the stratum spinosum, with a peak at 24 h. Within 24 h a strong upregulation of epidermal
fatty acid binding protein (E-FABP) was noted, with a peak at 7 days after injury. Cellular proliferation in the basal layer was increased fivefold as assessed by nuclear staining for the
Ki-67 antigen, showing a peak at 48 h. Surprisingly, no significant induction of
cytokeratin 16 and SKALP/
elafin expression, two markers associated with epidermal hyper-proliferation and
inflammation, was seen. These findings suggest that the cellular changes following exposure to
detergent are distinct from those seen in other forms of skin injury. We would speculate that the epidermal response to
detergent exposure is primarily directed at restoration of barrier function.