Damage to the skin by repetitive washing.

Damage to the skin following the repeated use of 2 different wash solutions was investigated. Stratum corneum capacitative resistance, stratum corneum lipids, transepidermal water loss, skin surface pH, laser Doppler flow and skin reddening were determined. All skin function parameters already showed a marked change after a single wash (e.g., the median of TEWL values increased by more than 0.5 g/m2 h). Repetitive washing for 1 week led to a further deterioration of TEWL and corneometry values (e.g., TEWL increased for about 2.9 g/m2 h after repetitive washing with sodium lauryl sulfate). The rate of skin function regeneration after repetitive washing was unaltered compared to regeneration after a single wash. The surfactants used showed quantitatively differing effects on corneometry, TEWL and laser Doppler flow (e.g., after repetitive washing with Geliderm, the median of TEWL values increased only up to 1.55 g/m2 h). However, damage arising from repetitive washing could not be completely prevented by the selection of a mild surfactant. Skin function regeneration showed no difference with the 2 surfactants used.