Contact Urticaria due to Dinitrochlorobenzene

ABSTRACT

A 33-year-old man with alopecia totalis presented with facial erythema and flares, conjunctival injection, and dyspnea developed within several minutes following the ninth application of dinitrochlorobenzene (DNCB). A scratch skin test produced positive reactions in concentrations of 0.01, 0.05, 0.1% DNCB showing flares and wheals, whereas concentrations of 0.001, 0.01, 0.05% diphenylcyclopropenone (DPCP) showed negative results. Contact urticaria due to DNCB is very rare, but this complication must be fully noted because of the widespread and frequent use of DNCB in dermatotherapeutic fields. We report herein a rare case of contact urticaria following topieal application of DNCB in the treatment of alopecia totalis.