182 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS In another study (41), a solution of 5% hexachlorophene in dimethyl phthalate was applied to 50 subjects. Patches were allowed to remain on the skin for 48 hours and 10 such applications were made followed by a challenge test after a two-week rest period. Only one subject showed a continuous reaction in the form of slight erythema. We can give no explanation why hexachlorophene when dissolved in propylene glycol is quite irritating to the human skin but is so to a much lesser degree when dimethyl phthalate is used as a solvent. There were no reports that soaps and cosmetics containing hexachloro- phene have photosensitizing properties up to the time when Wilkinson (42) in 1961 found that 3,3',4',5-tetrachlorosalicylanilide in soap was the agent responsible for outbreaks of contact dermatitis and photodermatitis in Eng- land, and Jillson and Baughman (43) established that bithionol, a bisphenol structurally related to hexachlorophene, is a primary photosensitizer. The question whether hexachlorophene might act similarly was re- examined and a few cases of photocontact dermatitis where hexachlorophene is stated to be the primary photosensitizer have been reported by O'Quinn et al. (44) and by Freeman and Knox (45). However, it cannot be definitely excluded that previous contact with a photosensitizer might have led to the irritation by hexachlorophene. Similarly, the four patients who, according to Epstein et al. (46), gave positive photopatch reactions with hexachlorophene, were also sensitive to other compounds. Persons photo- sensitive to tetrachlorosalicylanilide and bithionol showed cross-sensitivity to hexachlorophene (4:7, 4:8). Sensitivity to both bithionol and hexachloro- phene was also suspected by Gaul (4:9) in one patient and was reported for two patients by Epstein (50). SUMMARY AND CONCLUSIONS The toxicological properties of hexachlorophene have been described. Data on studies on experimental animals and on humans have been presented. The following conclusions may be drawn. The fairly high oral and systemic toxicity of hexachlorophene for animals presents no problems for its topical use by humans as long as misuses are avoided. Such misuses may consist in accidental ingestion of preparations containing hexachlorophene or in the contact of higher concentrations of hexachlorophene with broken skin or denuded areas of burns over longer periods of time. Shaved skin of rabbits and guinea pigs is irritated by hexachlorophcne. However, on human intact skin, it is well tolerated. Its allergic factor is

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