Patch test and photo-patch-test are carried out in patients with cosmetic dermatitis. The test results indicate that the untoward reactions to cosmetics are due predominantly to allergic sensitization rather than to primary irritation.
It is said that false negative reactions are common in testing with cosmetics, depending upon the test materials and test methods.
Five days or more after contact with the causative substance the sensitive states will develop. No sensitivity appears after repeated contact with cosmetics for many years in most individuals. Some may become sensitive after continual contact over a period of years.
The past history about the cosmetics has to be thoroughly inquired in patients with cosmetic dermatitis. All cosmetics that the patient has used must be taken into consideration. Cosmetics are used on the uncovered areas, so that photo-patch-test as well as patch-test must be carried out to determine the causatives. Thus, false negative reactions are avoidable.
A trial to determine the actual cause of sensitivity encounters the practical difficulties because of the industrial secret on cosmetic ingredients. Knowledge of the sensitizing ingredients of cosmetics is scanty.

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New experiments in odor-psychology which have been studied by PAUKNER and RANDEBROCK independently or in collaboration with each other are based on Osgood's semantic differential and Thurstone's factor analysis. In these procedures, it should be required to work statistically a great deal of calculation and the use of computor helps make it easy them.

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In order to know some factors of hand cream-feeling, the rating scale was made by semantic differential procedure. The method gave clear discrimination in applying to four products on the market.
By means of correlation analysis, it was found that some factors on the comfortable feeling and on uncomfortable feeling for the consumers.
Then two important facts were estimated as follow:
1. The profiles of feeling were varied with the cutaneous conditions, rough or smooth.
2. Rough conditioned consumers were forced to use medical hand cream with uncomfortable feeling.

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The method to quantify p-hydroxybenzoates in cosmetics was studied.
In this experiment, the use of silica gel with 10% gypsum as thin layer, chloroform-isopropanol-N/10 potasium hydroxide (80:5:5) as solvent and myron reagent as indicator resuled in success.
By this method, we were not only able to determine the approximate quantity of whole p-hydroxybenzoates in cosmetics but to confirm the existence of these preservatives in o/w, w/o type emulsion or toilet water.
It can be considered that this method is useful on the quality control for the antisepsis.

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