Comparison of Results of Lactic Acid Sting Tests between Sensitive Skin and Nonsensitive Skin after Tape Stripping

Background: Sensitive skin has been described as a skin type showing higher reactivity than normal skin and developing exaggerated reactions when exposed to internal stimulants and external irritants. The Lactic acid sting test is a widely accepted method for evaluating sensitive skin and is employed for the selection of subjects experiencing invisible sensory irritation. Tape stripping of skin is a useful method for removing stratum corneum which plays a most important part in the barrier function of the skin. Measurement of the transepidermal water loss (TEWL) is the standard method to determine stratum corneum barrier status. A disturbed skin barrier is characterized by high TEWL. Objective: The author performed this study to compare lactic acid sting test between sensitive skin and nonsensitive skin after tape stripping, not on the face but on the forearm. Methods: A total of 40 individuals (20 individuals of the sensitive skin group and 20 individuals of the nonsensitive skin group) were selected by the method of self-assessment questionnaires related to sensitive skin. The individuals were tested a total of 6times, at internals of 2weeks, on the volar aspects of both forearms with 10% lactic acid after tape stripping, with or without a Hilltop chamber. The frequency of tape stripping was divided according to the TEWL into 3 groups as follows: mild(increase of TEWL5g/mh compared to baseline TEWL), moderate (10g/mh), and severe (20g/mh). Results: When 10% lactic acid sting tests were performed after mild and moderate tape stripping of skin, irrespective of the Hilltop chamber, there were more positive responders in the sensitive skin group (p