Chloracne duration

Accidental exposure to 2,3,7,8-TCDD in a 1949 explosion in a trichlorophenol plant in Nitro, West Virginia, resulted in an outbreak of severe chloracne. Moses et al. (1984) conducted a cross-sectional survey of workers in this plant in 1979. In reviewing the impact of the accident, the authors indicated that 117 workers had severe chloracne as a result of the explosion however, 111 additional workers were found to have had chloracne prior to the explosion. A cross-sectional study of 226 workers in 1979 indicated that 52% had chloracne which persisted for 26 years, and in 29 subjects it was still present after 30 years. Blood levels were not measured, but the air dust in the plant was suspected to have contained 2,4,5-T contaminated with 6 ppm 2,3,7,8-TCDD compared to 0.1 ppm in later years. Similarly, high incidences of chloracne were also found in other facilities (Jirasek et al. 1976 May 1973 Poland et al. 1971 Vos et al. 1978). Appearance of chloracne after accidental occupational exposure may be immediate or delayed since workers may not always be removed from the work environment, the duration of exposure and total exposure is difficult to assess. 

Skin lesions from environmental exposures to 2,3,7,8-TCDD have been most thoroughly studied in the population exposed in Seveso, Italy. Reggiani (1980) described dermal lesions for 17 persons (primarily children) hospitalized shortly after the accidental release in Seveso. Acute lesions probably due to alkali and bums were observed immediately and had a duration of up to 2 months chloracne in children occurred within 2 weeks (earliest occurrence was 3 days) and usually persisted for 8-26 months. Irritative lesions (characterized by erythema and edema of exposed areas, vesiculobollus and necrotic lesions, and... 

Hepatic Effects. Exposure to 2,3,7,8-TCDD induces liver microsomal enzymes in both humans and animals, regardless of the route or duration of exposure. Increased urinary -glucaric acid (UGA) excretion, an indirect index of enzyme induction, was found in children with chloracne living in the Seveso area following the 1976 industrial accident (Ideo et al. 1982). Biochemical changes (increased... 

Acute-Duration Exposure Acute exposure of humans to 2,3,7,8-TCDD can cause chloracne and hepatic effects (Goldman 1973 Reggiani 1980). Specifying the route of exposure in these human cases... 

Chloracne tends to resolve slowly upon cessation of chemical exposure. Its duration correlates with the severity of the disease, which usually reflects the degree and extent of exposure. The severely exposed victims of Yusho in 1968 had characteristic chloracne lesions that continued to develop for as long as 14 years postexposure. 

Chloracne and associated dermatologic changes are widely recognized responses to TCDD and other dioxin-like compounds in humans. Chloracne is a severe acne-like condition that develops within months of first exposure to high levels of dioxin. For many individuals, the condition disappears after discontinuation of exposure, despite serum levels of dioxin in the thousands of parts per trillion for others, it may remain for many years. The duration of persistent chloracne is on the order of 25 years although cases of chloracne persisting over 40 years have been noted [180]. 

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