SELF-PERCEPTION OF SENSITIVE SKIN 271 Peak Grade- Burning/Stinging 1.45 1.09 2.20 2.00 0.92 0.58 LA BP CHLOR ] ß Sensitive [] Non-Sensitive I Figure 3. Peak intensity of burning/stinging. Table I Time to Peak Response/Grade at Onset Time to peak response BP LA Chlor/meth Sensitive skin 6:35 4:40 1:42 Non-sensitive skin 7:14 6:12 1:59 Grade at onset BP LA Chlor/meth Sensitive skin 0.84 0.71 1.43 Non-sensitive skin 0.69 0.49 1.36 (oily/normal) skin, and slightly fewer had neither dry nor oily skin. Similar percentages of dry and oily skin were reported. A significantly larger percentage of the sensitive group reported that their sensitivity had increased over the years (45% vs 14%). There were no significant differences between the responses at the five geographically diverse locations. When subjects were categorized into age groups (20s, 30s, 40s, 50s, 60s), analyses indicated that the balsam of Peru responses were significantly lower in the older age groups. Lactic acid and balsam of Peru responses were significantly higher for those who indicated they purchased products specified for sensitive skin. Subjects with skin types I and II had higher peak grades than those with skin types III and IV. Differing skin color or skin tone did not indicate a difference in response to any of the probes. Subjects who indicated that their sensitivity had changed a little or much more had higher scores for all three probes. While some of these observations showed statis- tically significant differences, the only one that appeared to be clinically significant was the age group response to balsam of Peru.

272 JOURNAL OF COSMETIC SCIENCE lOO Percent of Non-Responders 75- 50- 25- 22 36 54 'I 36 7 11 BP LA CHLOR I ß Sensitive [] Non-Sensitive I Figure 4. Percent of non-responders. Peak responses to the chemical probes and demographic profile information were ana- lyzed using Pearson's correlation coefficient. None of the following comparisons to peak grade indicated anything more than a trivial relationship to a subject's peak response to any of the three chemical probes: overall skin condition, skin tone, skin type, sun exposure, blushing categories, smoking status, and allergies. SUMMARY/DISCUSSION "Sensitive skin" is a term that has a very distinct meaning to each individual, but over a large group the definition is variable. In the literature, sensitive skin has been assessed with a facial sting test, involving a potentially strong irritant like lactic acid applied to the nasolabial fold (2). Tests conducted with materials like lactic acid, chloroform/ methanol, or balsam of Peru can identify individuals with sensitive skin (3-5). The current epidemiological study was undertaken to compare individuals who classified themselves on a written questionnaire as having sensitive skin with a group of indi- viduals self-classified as having non-sensitive skin. In this multisite study involving over 1000 participants, subjects completed a self-assessment questionnaire categorizing themselves as having sensitive or non-sensitive skin. Each subject underwent neurosen- sory testing with solutions of lactic acid, chloroform/methanol, and balsam of Peru. With each of the chemical probes, a statistically significant difference was found be- tween the responsiveness of the self-assessed sensitive skin and non-sensitive skin groups for the time to onset and the peak grade achieved for each of the probes. Other param- eters indicated directional differences between the self-assessed groups. The overall results indicated that the self-assessed sensitive skin group was more sensitive to the facial sting tests on average than the self-assessed non-sensitive skin group. However, the number of non-responders in the sensitive skin group and the number of strong re-