Cutaneous histologic findings in chemical workers with and without chloracne with past exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin

Histopathologic examination of the skin in seventy-seven chemical workers with past exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was performed in 1981 to determine whether changes specific for chloracne were present. Prior to biopsy, subjects had been classified as having clinical evidence of residual chloracne (48%), having a past history of chloracne but no current dermatologic evidence of it (24%), or never having had chloracne (27%). Follicular infundibular dilatation and/or comedones and cysts were found in 76%, 39%, and 32% of the current, past, and never chloracne groups, respectively; the differences were significant between current and never groups (p less than 0.001) and between current and past groups (p less than 0.01). A combined mean score of follicular infundibular dilatation, comedones, and cysts was significantly different only between the current and never groups (p less than 0.005). Solar elastosis, histologically present in all subjects, was related to age but not chloracne. No relationship was found between smoking habit and any of the histologic findings. Changes specific for chloracne were not found. Four-millimeter skin biopsy is unlikely to be either diagnostic or useful in persons with past exposure to TCDD that is ill defined or insufficient to produce chloracne.