Abstract:

Sensitive skin is a series of skin symptoms of unpleasant subjective feelings caused by the slight stimulation of skin response. It may produce a series of subjective and objective manifestations such as tingling, itching, erythema, tingling, and burning. Its main characteristics are subjectivity and responsiveness. It is a highly reactive skin condition, which is not a skin disease, but it is more likely to occur with skin disease, and it can be considered as a skin manifestation of some skin diseases. Sensitive skin may occur in various parts of the body and is not necessarily accompanied by objective signs such as erythema. Sensitive skin may be precipitated by various factors that its occurrence mechanism is complicated and unclear, involving skin barrier, nervous system, immune response, vascular system and many other aspects. The occurrence of sensitive skin is closely related to the TRP family, especially the TVPR1 receptor, which is generally accompanied by damage to the skin barrier and （or） nervous system disorders. The evaluation methods of sensitive skin condition can be divided into subjective evaluation methods, semi-subjective evaluation methods and objective evaluation methods. The lactic acid sting test and the measurement of transdermal water loss are the mostly used. At present, lots of researchers are exploring more objective and accurate evaluation methods for sensitive skin. However, due to the random occurrence and unclear mechanism, many evaluation methods have the limitations of poor consistency, low recognition rate, and difficulty in repeatability. The incidence of sensitive skin in the population is relatively high which about 40%, and there are differences in the incidence of different countries. At the same time, as cosmetics companies pay more attention to sensitive skin, it is showing a blowout trend in the market that more and more cosmetics claim suiting for sensitive skin. The efficacy claim of cosmetics should have sufficient scientific basis. The “Evaluation standard of cosmetic efficacy declaration” requires that specifically declared cosmetics should be evaluated by human efficacy evaluation test or consumer use test if they claim to apply to sensitive skin. Therefore, it is very important to accurately assess the condition of sensitive skin. Starting from the precipitating factors and occurrence mechanism of sensitive skin, this paper elaborates the subjective and objective identification and grading methods of sensitive skin, aiming to provide a theoretical basis for establishing a sound evaluation system of applicability and efficacy of sensitive skin cosmetics.

Key words: sensitive skin, assessment method, precipitating factor, occurrence mechanism