CONTACT SENSITIZATION DUE TO PERFUMERY RAW MATERIALS 319 Baer, R. L. in MaclKenna, R.M.B., Modern Trends in Dermatology 232 (1954) (Butterworths, London) Schulz, IK. H. Arch. klin. u. exp. Dermatol. 211 253 (1960) Voss, J. G. J. invest. Dermatol. 31 373 (1958) Sulzberger, M. B. J. Allergy 18 92 (1947) Friederich, H. C. and Witjens, P.H. løarfiimerie u. Kosmetik 39 893 (1958) Nilzen, A. Acta Dermato-Venereol. 38 104 (1958) x2Skog, E. Acta Dermato-Venereol. 38 1 (1958) Introduction by the lecturer I would like to stress that skin sensitization with man due to perfumery is a phenomenon of rare occurrence. Nevertheless a careful observation of these phenomena is fully warranted. The quantities of perfume being used in some form or other are rising steadily. This is especially applicable to perfume compounds incorporated in end-products based on highly surface active materials, which will naturally promote an intensive contact with the skin. It is a happy coincidence that the study of contact sensitization, especi- ally due to simple organic chemicals, is starting to emerge from a purely empirical one and has recently been treated more and more by a more fundamental approach. In these theoretical considerations, especially with regard to the chemical aspects, the experience in perfumery, with its raw materials, covering nearly the entire field of organic chemistry, will no doubt be of much value. Likewise, knowledge obtained in this way may serve the perfumery chemist as a guiding principle and as an additional source of reference in the study of the dermatological properties of new perfumery chemicals. In particular, the tendency in perfumery chemistry to replace natural products, where the dermatological behaviour is traditionally known, by synthetic chemicals may introduce the necessity of careful evaluation of the possibility of an adverse effect in contact with the skin. The experimental approach to the phenomenon of skin sensitization is rather difficult owing to the fact that contact sensitization is not a general response of the human organism, but a rather exceptional and individually abnormal reaction on a normally harmless contact of foreign materials with the skin. In order to study the physiological and chemical backgrounds of contact sensitization in man, the investigator has, in general, to confine himself to a very limited group of test subjects. On the other hand, there is the possibility of studying sensitization effects on animals (rabbits and guinea pigs) but we have to realize that the effects produced in those animals are probably different from those to be expected with man.

320 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS DISCUSSION MR. G. L. GARDEL: May I assume that your research was carried out on single products, and that you did not use them in combination with other materials? I have found, from experience, that this sort of behaviour can be expected with single products, but when they are mixed with other compon- ents in a perfume compound, there is no effect whatsoever. TI•E LECTURER: I agree with that experience, and there are several possible reasons for this. In the first place, the concentration of the product is appreciably lowered in this way. Another reason is that the process is not finished when the material is applied to the skin, is in fact just com- mencing. The product has to penetrate the skin to a certain extent and has to react with other organic structures. All these processes may be influenced or interrupted by the presence of, say, 99% of other materials. Even the way in which the material is applied, e.g. in a cream base, an alcoholic solution, etc., may have an influence on the dermatological response. MR. B. tz[. KINGSTON: IS it not possible that the presence of alcohols, normally present in perfume blends, will render innocuous the aidehyde and ketone sensitizers, due to the formation of aceta!s and ketals ? THE LECTURER: Yes. MR. D. BAss: Do you have any experience of perfumes irritating the eyes ? I think it is common practice to perfume eye lotions. There are certain detergents available for baby shampoos, that do not irritate the eyes or sting them. Is there a perfume that does not irritate the eyes ? THE LECTURER: I think this is quite another problem. You are dealing here with primary irritation, and this is essentially different to sensitization. Primary irritation is a more direct reaction on nerve endings and an effect which is reproducible by all humans. Sensitization is just an effect that occurs after repeated application of much lower concentrations that are not irritant as such, and only affect a small proportion of people--it is not the normal reaction. As far as the eye irritation is concerned, one experiences a feeling of pain in the eyes due to a difference in osmotic pressure and this will safe- guard the eyes against prolonged contacts with foreign materials. Even plain distilled water stings the eyes, because it is not isotonic. As far as the shampoos are concerned, I consider it better to have a shampoo that stings, rather than one that gives no pain but which might be harmful one is not warned in the second case and that may be much more dangerous. DR. J. H. }V[ERZ: Do you find that a whole group of sensitized people are sensitive to the same sort of materials, or is it a question of idiosyncrasy--one person may be sensitive to one thing and someone else to another.