Chloracne: still cause for concern.

Chloracne, first described by Herxheimer in 1899, is a dermatosis consisting of more or less diffuse acneiform lesions distributed prevalently on the face and on body areas not usually affected by acne and caused by chronic or acute exposure to halogenated chemical compounds. Dioxin is the common name for dibenzo-p-dioxins and dibenzofurans, contaminants nearly ubiquitous in the environment and highly resistant to chemical and biological degradation. These compounds can survive for decades in the environment and accumulate in the human and animal food chains. Chloracne is characterized by the onset of numerous comedo-like lesions and yellowish cysts on the face, particularly on the cheeks, that can spread to the trunk and other body regions not usually affected by acne vulgaris, with diffuse grayish skin pigmentation and sometimes associated with hypertrichosis and areas of folliculitis. The lesions may occasionally be accompanied by skin or systemic manifestations. We report 9 cases of chloracne, 8 of them with rapid onset in patients residing in the same building, and 1 in a patient occupationally exposed to halogenated compounds. In our series, the doses of dioxin and polychlorinated biphenyls in the soil, water and plant material, and the serum titer of dioxin were within the normal range. This consideration raises the issue of the need to revise the serum threshold for dioxin poisoning and the environmental threshold. We wish also to underline the value of dermatopathology in the differential diagnosis of chloracn