The compound 1 - chloro - 2,4 - dinitrobenzene (DNCB) is a potent contact allergen that has been used in the past decade by many dermatologists for the treatment of benign skin disorders, such as recalcitrant viral warts1 and extensive alopecia areata.2 In this issue of the Archives, however, the investigations of Black et al3 cast serious doubts on the use of DNCB. This editorial provides further arguments against the use of this compound.
Five years ago, two groups of independent investigators found that DNCB acts as a mutagen in the bacterial plate incorporation assay (Ames test).4,5 Both groups used various strains of Salmonella typhimurium as indicator organisms, and both groups obtained positive results with and without metabolic activation by rat liver S-9 fraction, a homogenate containing hepatocellular microsomes. Moreover, Summer and Göggelmann5 showed that DNCB depletes the activity of glutathione S-transferase in rat skin,