Sodium Lauryl Sulfate-Induced Irritation in the Human Face: Regional and Age-Related Differences

Abstract

The particular sensitivity of the human face to care products prompted us to study irritation induced by sodium lauryl sulfate (SLS) in its various regions. We examined regional and age-related differences, correlating basal transepidermal water loss (TEWL) and capacitance to SLS irritation. SLS (2 % aq.) was applied under occlusion for 1 h to the forehead, cheek, nose, nasolabial and perioral areas, chin, neck, and forearm to two age groups – ten young subjects and ten older subjects. TEWL was measured before and 1 h and 23 h after patch removal. Baseline stratum corneum hydration was also measured. Irritation was assessed by the changes in TEWL (δTEWL = TEWL after patch removal – basal TEWL) after corrections to the control. In the younger group, all areas of the face and the neck reacted to SLS, whereas the forearm did not. In the older group, the nose, perioral area, and forearm did not react. In both age groups, some significant differences between the regions of the face were detected. The younger group showed higher changes in TEWL than the older group in all the areas studied, but only in the chin and nasolabial area were the differences statistically significant. Significant correlations were found between basal TEWL and δTEWL in five of the seven areas which reacted to SLS. Baseline TEWL is one parameter that correlates with the susceptibility of the face to this irritant.