OBJECTIVE This study evaluates prevalence and characteristics of sensitive skin in the United States and China, compares data collected from the two countries and two methods, and examine possible factors that may be associated with sensitive skin.METHODS A self-assessed questionnaire was answered by each of 1626 women and 165 men from the United States and 649 women and 143 men from China, randomly selected, who were over the age of 18 years old and lived in Greater Dallas area, TX, USA and Shanghai, China, respectively.The US subjects consisted of 22.5% African Americans, 7.1% Asians, 57.3% Caucasians, 10.9% Hispanic, and 2.1% "Others" which was defined by unknown or unreported ethnicity.The survey required subjects to identify whether or not they perceived their skin to be sensitive.Then a diagnostic test was performed on all selected subjects with 10% aqueous lactic acid at two test facilities (Richardson, TX and Shanghai, China).Positive results of the test are an indication for clinically-diagnosed sensitive skin.RESULTS Twenty nine percent of the US subjects including 29% of women and 25% of men described themselves as having sensitive skin.Asians had the highest incidence of self-perceived sensitive skin (48%), followed by African Americans (30%, P <0.01), Caucasians (28%, P < 0.01), "Others" (26%, P < 0.01), and Hispanic (20%,P <0.01).The 30 s and 40 s age groups reported slightly heightened incidences of sensitive skin compared to other age clusters (30%-31% vs.24%-28%).Subjects with light and dark skin reported a similar incidence of sensitive skin (35% and 36%) and both were significantly higher than that for medium skin tone subjects (P <0.01).Incidence of self-perceived sensitive was reported the highest in dry skin subjects (53%) and lowest in normal skin subjects (23%).Results of the lactic acid test indicated that 57% of the US subjects had clinically diagnosed sensitive skin.Prevalence of sensitive skin in women was slightly but significantly higher than that in men (57% vs.55%, P <0.01).Asians and Caucasians had the same and highest (63%) prevalence of sensitive skin, followed by "Others"(52%),African Americans (47%), and Hispanic (47%).Light skin subjects showed the highest prevalence of sensitive skin (64%) and dark skin subjects had the lowest (52%) (P <0.01).Medium skin tone subjects showed a medium prevalence of sensitive skin in between, which was significantly lower than that of light skin subjects (64% vs.55%, P < 0.01).Differences among age and skin type groups were slight and insignificant.In the 792 Chinese subjects tested, 62% (488) were clinically diagnosed with sensitive skin.Women had a higher prevalence of sensitive skin than men (63% vs.57%, P<0.05).Compared to the US subjects, either Chinese women or Chinese subjects in total showed significantly higher prevalence of sensitive skin than their US counterparts (63% vs.57%, 63% vs.57%, P <0.05).When compared to Asian or Caucasian group of the US subjects, the Chinese subjects showed a very similar prevalence of sensitive skin (62% vs.63%, P > 0.05).The 30s and 40s age groups showed the highest prevalence of sensitive skin (68%, 70%), which were significantly higher than either younger (less than 30) or older groups (50-59 years, 60 or greater, P < 0.05).Comparisons between data collected from the two diagnostic methods showed that 68% of the US subjects with selfperceived sensitive skin were clinically diagnosed to have sensitive skin, while 30% of them failed clinical diagnosis.The results also showed 42% of self-perceived non-sensitive skin subjects were clinically certified, though 53% of them were clinically diagnosed to have sensitive skin.Overall, 20% of the US subjects were both self-and clinically-diagnosed to have sensitive skin, accounting for 34% of the subjects who were diagnosed clinically alone.CONCLUSION This study, based on two samples of different populations and two different diagnostic methods, reveals a high prevalence of sensitive skin in the US and China.Ethnicity, sex, skin tone and skin type, and age may be factors associated with sensitive skin.Although self-perceived sensitive skin subjects were more likely to be diagnosed clinically than selfperceived non-sensitive skin subjects, the two diagnostic methods did not correlate well.Therefore, it is recommended to test a product designed for sensitive skin consumers utilizing panelists who are both self-and clinically-diagnosed as having sensitive skin.