BASE-LINE BIOPHYSICAL PARAMETERS IN SUBJECTS WITH SENSITIVE SKIN

Sensitive skin has been described as a skin type showing higher reacti vity than normal skin and developing exaggerated reactions when expose d to external factors. The stinging test, performed by applying lactic acid to the nasolabial fold and evaluating the intensity of subjectiv e symptoms, is widely accepted as a marker of sensitivity and employed for the selection of subjects experiencing invisible cutaneous irrita tion. However, this test is based on self-perceived assessment and lac ks objectivity. In order to contribute to the finding of objective des criptors, we assessed baseline biophysical parameters in subjects with sensitive skin by means of transepidermal water loss (TEWL), capacita nce, pH, sebum and skin colour measurements, and compared the data wit h those obtained in normal subjects, also correlating the results with those of clinical assessments and functional tests. Subjects with sen sitive skin showed a trend towards higher scores at all assessment tim es both for the stinging and the washing test. The skin of sensitive s ubjects was described as less supple, less hydrated and more erythemat ous and telangiectatic with respect to the skin of normal subjects. A trend towards an increase in TEWL, pH and colorimetric a values, and a decrease in capacitance, sebum and colorimetric L values on the fac e of subjects with sensitive skin was observable. However, significanc es were only present for capacitance and a values. Thus, alterations of baseline capacitance values indicate the tendency to barrier impair ment and support the view that skin hyperreactivity to water-soluble i rritants is induced by a greater amount of irritants absorbed, whereas the increase in the erythema parameter shows that cutaneous vascular hyperreactivity in subjects with sensitive skin also corresponds to ba seline vasodilation.