EFFICACY OF ANTIDANDBUFF FOBMULATIONS 75 Corneocyte Counts Originally we developed this procedure in order to recover bacteria quan- titatively from the skin surface. The details have been presented elsewhere (8). The method is applicable to dandruff appraisal for it removes the des- quamating portion of the horny layer. Since there is an increased production of horny cells in dandruff as shown by the accelerated migration of radio- labeled basal cells to the surface (9), corneocyte counting affords a means to determine the quantity of horny cells per square centimeter produced in a given time. Briefly, a site on each side of the vertex was clipped so that a glass cylinder of 3.8/cm 2 area could be snugly applied to the surface. One milliliter of buffered 0.1% Triton X-100* was placed in the cup and the surface was rubbed with a blunt Teflon rod {or 1 min. The wash fluid was aspirated and the procedure was repeated. The two samples were pooled. After appropriate dilution, usually 1:10 but with lesser dilutions after effective treatment, two drops of 2% crystal violet were added, the cell suspension was agitated me- chanically, and the dispersed cells were counted in a Fuchs-Rosenthal hemo- cytometer. Shampooing This always consisted of two 1-min latherings with a rinse in between. Prevalence of Dandruff The incidence of dandruff in the healthy population is not really known. The results of different surveys are of course keenly dependent on the criteria used. Cohen examined 500 young women and graded 15% as having 2-t- dandruff (10). Bourne and Jacobs evaluated 2720 soldiers and classified 2.5% as having "gross dandruff" (11). Roia and Vanderwyk considered that 70% of the population had some degree of dandruff (12). Obviously, these in- vestigators did not employ the same rating system. Procedure Over a 3-year period 1,033 unselected adult males were graded as above 4 days after a nonmedicated shampoo. None were using antidandruff medica- tions. Results The frequency distribution is shown in histogram form (Fig. 1). The most frequent score was 2 the median was 3. Eighteen per cent were classified as grade 5 (moderately severe dandruff) or higher. Grade 4 (mild dandruff) *Rohm & Hass Co., Philadelphia, Pa.

76 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS 2t00[ 200 IOO I 6 7 8 9 I0 ( rede Figure 1. Histogram showing frequencies of the various grades of scaling in an tin- selected adult male population included another 18%. Only 4.5% had severe dandruff (grades 6 and 7). Tak- ing grade 4 as mild dandruff, the greatest proportion of subjects fell into the nondandruff group. Comment Since we do not admit subjects to clinical efficacy studies with grades of less than 5, it is clear that we reject 4 of 5 prospective candidates. We would agree with Van Abbe and Deans' assertion that it is surprisingly difficult to recruit good subjects (4). Seasonal Variation It is commonly supposed that dandruff declines in the summer though no clear proof has been brought forward. The sales of antidandruff products ap- parently decrease in that season, though this might be interpreted in different ways.