ABSTRACT
Monobenzone is a monobenzyl ether of hydroquinone with topical depigmentation activity. Although the exact mechanism of action of depigmentation is unknown, the metabolites of monobenzone appear to have a cytotoxic effect on melanocytes. Monobenzone has been used since the beginning of the 1950s to treat several forms of hyperpigmentation. In this chapter, only allergic contact dermatitis to monobenzone is discussed. The patient undertook a ROAT with monobenzone 5% cream at an unaffected site and this produced a similar dermatitis. Patch tests were positive to the cream, to monobenzone 2% pet. As part of a clinical study to determine the effectiveness of monobenzone as a depigmenting agent, simulated use tests were done on a group of 43 middle-aged and older dark-skinned subjects with normal skin. Monobenzone in a vanishing cream base 1%, 4%, 7% and 10% was applied for 4 months plus the base itself. A patch test with the 10% monobenzone cream was applied to 12 who had leukoderma.
