J. Sac. Cosmetic Chemists t8 215-223 (1967) •) 1967 $ooiety of Cosmetic Chemists of Great Britain Reactions materials to artificial colouring C. D. CALNAN* Presented at the Symposium on "Colour", organised by the Society of Cosmetic Chemists of Great Britain in Eastbourne, Sussex, on 27th April 1966. 81rnop.•is--Artificial colouring agents are probably the most frequent single cause of allergic reactions to cosmetics. The greatest number are attributable to halogenated fluoresceins. The responsible agent appears to be an impurity, although it may well be chemically related to the parent substance. Apart from cosins, several colouring materials, includiag rhodomine, lakes and azo dyes, have produced allergic dermatitis. A troublesome yellow-orange dis- colonration of the nail plate has been noted since the introduction of yellow dyes and lakes into nail lacquers. During my intermittent discussions with experts in the cosmetic industry over a number of years I have been given the impression that the perfume content of cosmetic products is suspected as the most likely cause of a dermatitis or other adverse reaction forming the basis of a customer complaint. I have, however, never been able to determine the evidence for this point of view. My own experience is based on the investigation of cases of dermatitis or other reactions from cosmetic products, seen in a special clinic at a large hospital for diseases of the skin in London. Al- though there is evidence that the number of patients with allergic reactions to perfumes in cosmetics is increasing, they still constitute no more than quite a small proportion of all cosmetic reactions. In the patients whom I have seen, the major cause of allergic reactions to cosmetics is the colouring material. The major proportion is from colours in lipsticks while the rest is made up from colours in face creams, powders, rouges and toilet pre- parations, such as after-shave lotions. LIPSTICK Reactions to lipsticks appear to be accepted as an "occupational hazard" -- *The Institute of Dermatology, London, W.G.2. 215

216 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS by both the users and manufacturers. I cannot recall any instance in which a woman has pursued a claim for injury resulting from allergic sensitivity to a lipstick. Perhaps they simply do not come to my attention. There are probably many instances of minor "reactions" of a non-specific character to lipsticks, in which the user simply discards the stick and purchases another. The precise cause can rarely be identified. I see a small number of such cases. They are not allergic. Allergic sensitivity usually produces a self-evident inflammation of the lips. Only about one in 10, or less, of these cases can be traced to the perfume, wool alcohols, a wax or other constituent of the base. Nine out of ten or more are traceable to the colouring agent, and most to the halogenated fluorescein. However, patients who are allergic to eosin are not necessarily quite unable to use any lipstick containing eosin. There are three main reasons for this anomaly. First, eosin is adsorbed by keratin at the slightly acid pH which exists on the skin surface of the vermilion of the lips, and penetrates only weakly through the epidermis. Secondly, the major allergen or dermatitic agent in most commercial samples of eosin is probably a minor constituent and present in quite small amounts. And thirdly, there are differences in the dermatitic potential of the various halogenated fluorescein derivatives which are used in lipsticks. Therefore, a low concentration of an eosin may be tolerated by a person who is only weakly sensitized, as a result of all the eosin combining with the surface keratin and not enough being absorbed through the horny layer to produce a reaction. The concept that allergic reactions may be due to impurities is well known. Many new drugs are known to produce more adverse reactions in their early stages of development than when they have been refined to a greater and greater degree. In lanolin the actual derma- titic constituent may frequently be a wool alcohol present in a concentration well below one per cent. Hjorth (1) has shown that tn balsam of Peru the main allergen or dermatitic agent is coniferyl benzoate, or a polymer from its esters, which comprises no more than about 2% of the balsam. Com- parative skin testing in allergic patients with a series of halogenated fluoresceins is not as rewarding as one might hope because the biological reactions produced in the skin are often not sufficiently clear cut to be measured objectively. Suffice it to say that, in general, the iodinated derivatives are consistently less reactive than the brominated or chlorinated ones. Cosmetic chemists have informed me that the number of lipstick customer complaints can sometimes be related to the manufacture of their