Chloracne, "the hallmark of dioxin intoxication".

Clinical experiences and laboratory studies are described involving a population of workers who were exposed in a plant making 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), including a trichlorophenol runaway reaction. Workers were followed for a period of four years, and 30 years later a mortality analysis was done on those exposed to runaway reaction material to determine possible increased risks for causes of death. Subsequently, a morbidity study on 436 employees involving three cohorts was carried out to determine the long-term health effects associated with the production of 2,4,5-T including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The mortality and morbidity studies demonstrated that the standardized mortality ratio for all causes of death was 69, and for cancer at all sites and cardiovascular disease it was 100 and 68, respectively. The most significant observations emerging from the morbidity study were that 86% of the exposed persons developed chloracne at some time and that 52.7% still had chloracne on examination 20 to 30 years after the initial exposure. There appeared to be no evidence, on a long-term basis, of increased risks for cardiovascular disease, hepatic disease, renal disease, central and peripheral nerve problems, reproductive problems, or birth defects among the exposed and those who had chloracne among the exposed. Studies on the cell kinetics and pathogenesis of chloracne indicate that TCDD induces the modulation of undifferentiated sebaceous gland cells to keratinocytes. This action results in a disappearance of sebaceous glands and substitution of closed comedones and keratin cysts. Production workers have the highest frequency and severity of chloracne and systemic effects.(ABSTRACT TRUNCATED AT 250 WORDS)