SKIN REACTIONS TO COSMETIC PREPARATIONS 17 blindness have been recorded from dyeing eyelashes. Symptoms decline gradually as oxidation of the dye occurs but may persist for weeks or months while any of the dye remains in contact with the skin. Bleaches Alkaline bleaching agents (peroxide activated by ammonia), can produce scalp or face irritation. Setting lotions Gums and mucilages with paraben antimicrobial agents. Lacquers Shellac or synthetic resins such as polyvinyl chloride or polyvinyl pyrrolidone in alcohol. Conditioners Oily emulsions which may contain beer, eggs, lanolin, cholesterol, waxes, perfumes and preservatives. Contact dermatitis may be due to any of these agents, usually the lacquer. The eyelids, retroauricular folds, forehead and neck are effected. Brilliantines and scalp dressings These contain mineral and vegetable oils, azo dyes and perfumes. Solid preparations contain waxes, resins and petrolatum. Lotions contain alcohols or Bay rum (essential oils of rum, clove and cinnamon), sometimes rube- facients to encourage hair growth, e.g. chloral hydrate, quinone with organic acids, cantharides, capsicum, cinchona, resorcin, camphor, tar and its derivatives, and emulsifiers. Contact dermatitis may appear on the eyelids, forehead, retroauricular folds, neck, finger clefts and backs of hand•, finger tips, and occasionally on the scalp. The most likely irritants include the perfumes and preservatives, solvents, rubefacients, potassium carbonate, quinones, pyridine compounds, denatured alcohol, resins, balsams, emulsifiers, and colourants. Vigorous massaging of the scalp with counter irritants or rubefacients increases the risk of pro- voking scalp irritation and contact dermatitis. The hands of the hairdresser are more likely to suffer than the scalp of the individual. Shampoos Hair loss rather than contact dermatitis is more likely to follow excessive use. Possible sensitizers include perfumes, preservatives, dyes, solvents and sulphonated oils. Increased secretion of oil and scalp irritation has been

18 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS ascribed to a product containing alkyl benzene sulphonate and selenium sulphide. According to Bereston (22) 31% of a series of patients developed excessive oiliness. 19% of those with grey hair noted an orange tinting. Sensitization to selenium is seen occasionally. Permanent waving Again the main hazard is to the hairdresser's hands rather than to the individual's scalp. Waving is effected by softening the keratin with an alkaline keratolytic (ammonia at pit 9), then twisting the hair on to rods, and re-fixing the keratin. Keratin is a linear chain polymer of various amino acids grouped into polypeptide chains. These are formed by weak amino and carboxyl link- ages, or strong disulphide links of cystine. In the waving process, the disulphide links are released chemically to su]phydryl, the keratin then becoming plastic. The agent is either alkali and heat in the conventional method, or by alkaline thioglycolates in cold waving. Thioglycollic acid is combined with ammonia or monoethenolamine. The preparation contains the usual perfumes and preservatives, gums, resins, lanolin and emulsifying agents. The solution contains 8.5% ammonium thioglycolate, the "home perms" contain only 6% at pit 9. The oxidizing neutralizer which fixes the keratin in its new form may be hydrogen peroxide, bromates or perborates. Thioglycolates at 10% strength are not primary irritants, but long continued use of alkaline thioglycolates irritates the skin of the hands, so protective gloves should be worn (23). Thioglycerine compounds are sensitizers, and are no longer used. Discolouration may occur in decompos- ing solutions owing to formation of sulphides. Schulz (24) reported 138 cases of sensitization, in 50ø/0 it was due to thio- glycollic hydrazide, and in 25% to glycollic ester, in others to ammonium thioglycolate and the amide of thioglycollic acid. Perfumes, emulsifiers, gums, resins and dyes are rarer causes. Existing seborrhoeic dermatitis of the scalp may be aggravated, and coniunctiv/tis has been reported occasionally. Disturbance in colour shades of partially oxidized para dyes by thioglycolates has been reported. Hair straightening Temporary removal of kinks and waves can be effected by gums (gum Karaya) or fatty petroleum/paraffin mixtures. More permanent "anti wave" is produced by fixation with petroleum jelly, and hot steel combs and press.irons. Cold "Perm" anti waves are given using sodium hydroxide (5-9%) with stearic and oleic acids, or thioglycolates.