HUMAN SKIN SURFACE LIPIDS 95 SUMMARY Acid number, as well as spreading index of the skin surface lipids differ for a given skin area from subject to subject. They both likewise distinctly differ for different skin areas and for some of the areas tend to rise during the warmer season. Some inferences of these results have been discussed. REFERENCES (1) Herrmann, F., and Prose, P. H., 5 e. Invest. DermatoL, 16, 217 (1951). (2) Prose, P. H., Baer, R. L., and Herrmann, F., Ibid., 19, 227 (1952). (3) Herrmann, F., Prose, P. H., and Sulzberger, M. B., Ibid., 21, 397 (1953). (4) Herrmann, F., Dermatol. u. Syphilis, 200, 3 (1955). (5) Sulzberger, M. B., 5 e. Soc. Cosmetic Chemists, 7, 175 (1956). (6) Harber, L. C., Herrmann, F., Mandol, L., and Sulzberger, M. B., 5 e. Invest. DermatoL, 29, 55 (1957). (7) Herrmann, F., Harber, L. C., Scher, R., and Mandol, L., At. M. At. Atrch. Dermatol., 76, 282 (1957). (8) Jones, K. K., •uart. Bull. Northwestern Univ. Med. School, 24, 253 (1950). (9) Jones, K. K., Science, 111, 9 (1950). (10) Ramsay, A. G., and Jones, K. K., Brit. •. Dermatol., 67, 1 (1955). (11) Kligman, A.M., and Shelley, W. B., 5 e. Invest. DermatoL, 30, 99 (1958). (12) Hodgson-Jones, I. S., and Wheatley, V. R., Biochem. •., 52, 460 (1952). (13) Moyle, V., Baldwin, E., and Scarisbruck, R., Ibid., 43, 308 (1948). (14) Boughton, B., Hodgson-Jones, I. S., MacKenna, R. M. B., Wheatley, V. R., and Worm- all, A., 5 e. Invest. Dermatol., 24, 179 (1955). (15) Rothman, S., "Physiology and Biochemistry of the Skin," Chicago, University of Chicago Press (1954). (16) Nicolaides, N., and Wells, G. C., 5 e. Invest. DermatoL, 29, 423 (1957). (17) Burtenshaw, J. M. L., "The Autogenous Disinfection of the Skin," in "Modern Trends in Dermatology," edited by R. M. B. MacKenna, New York, Paul B. Hoeber, Inc. (1948). (18) Rebell, G., Pillsbury, P.M., de Saint Phalle, M., and Ginsberg, D., 5 e. Invest. Dermatol., 14, 247 (1950). (19) Pillsbury, D. M., and Kligman, A.M., "Some Current Problems in Cutaneous Bacteri- ology," in "Modern Trends in Dermatology," 2nd series, edited by R. M. B. MacKenna, New York, Paul B. Hoeber, Inc. (1954). (20) Pillsbury, D. M., Shelley, W. B., and Kligman, A.M., "Dermatology," Philadelphia, W. B. Saunders, Co. (1956). (21) Blank, I. H., and Dawes, R. K., 5 e. Invest. Dermatol., 31, 141 (1958).

COSMETIC ALLERGY By N•ELS HJORTH, M.D.* Presented September 17, 1958, International Symposium, Copenhagen, Denmark NEARLY ALL PRODUCTS are capable of provoking allergic reactions in some of the consumers. Cosmetic allergic reactions are due to a sensi- tization to one or several of the ingredients. The major symptoms are itching, later redness and inflammation of the skin. Certain chemical substances have empirically been shown to be partic- ularly liable to give rise to allergic sensitizations. The sensitizing prop- erties of new, synthesized substances can seldom be predicted. However, in case of close chemical relationship to other substances with known high sensitizing potential, frequent sensitizations must be expected. This applies, for instance, to dyes related to para-phenylendiamine or to substances containing a para-aminophenyl radical. Likewise, cases of allergic reactions must be expected if the new substance is chemically related to sensitizers in common use by the consumers. Thus, house- wives who traditionally employ turpentine for household duties are liable to reactions from perfumes containing limonene or other terpenes. Apart from the chemical properties of a particular substance, the con- centration in which it is employed is all important for the incidence of sensitizations. Further, the vehicle may be of some consequence, partly by promoting the absorption of the substance, and partly because the surfactants used as emulsifiers in creams may induce a proliferation of the epidermal cells which has been shown to render the skin more susceptible to sensitization. The incidence of cosmetic allergy cannot be accurately estimated be- cause only a minority of the cases are seen by the dermatologists or are otherwise brought to the attention of the manufacturers. Among the 25,- 000 cases examined during the last twenty years at the greatest out- patient department here, only 550 cases could be ascribed to some cosmetic product as verified by a positive eczematous patch test. * The Finsen Institute, Copenhagen, Denmark. 96