Abstract
Diphencyprone is a potent topical sensitizer, but is non-mutagenic in the Ames test (unlike dinitroclorobenzene) and remains relatively stable in solution (unlike squaric acid dibutyl ester). Seventeen patients with total loss of scalp hair (eight alopecia totalis, nine alopecia universalis) were treated by maintaining on one sie of the scalp in allergic contact dermatitis induced by 2,3 diphenylcyclopropenone-1 (''diphencyprone''), and on the other side an irritant contant dermatitis using tretinoin gel (Retin A). After 20 weeks, treatment wiht tretinoin was stopped and diphencyprone was applied bilaterally for a further 10 weeks. Statisfactory regrowth of terminal hair on the scalp was achieved in only one patient. Eyebrow, eyelash and beard regrowth was achieved in one individual whilst in another, moderate, but not cosmetically satisfactory, scalp regrowth took place. In no patient did regrowth take place at trentinoin treated sites until after diphencyprone was substituted.