Skin disease after occupational dermal exposure to coal tar: a review of the scientific literature

Abstract

For about a century, coal tar has been used in industry and has been applied in the therapeutic management of several skin diseases. However, in the last decades the benefits of coal tar exploitation for humans could not outweigh its harmful effects on health. The aim of this study is to present the main adverse effects of coal tar on skin, with the emphasis on occupational exposure. The scientific literature indicates that dermal exposure to coal tar and coal tar pitches can be the cause of phototoxic reactions, irritation and burn, allergic dermatitis, folliculitis, occupational acne, atrophy of the epidermis, and hyperpigmentation. Moreover coal tar has been implicated in tumorigenesis, a relationship shown in numerous studies but not confirmed yet as the mechanism has not been fully clarified. A common finding in most studies is that exposure over a long period is the main risk factor for malignancy development, even in low exposure levels. Additional prospective, well-designed studies need to be performed to confirm the validity of the carcinogenic, mutagenic, and cytotoxic potential of coal tar on skin.

The influence of exposome on acne

“…Acne has been frequently observed in industry workers after prolonged exposure to certain organic molecules, such as coal tar or crude oil . Today, exposure to these molecules has become less common .…”

“…Today, exposure to these molecules has become less common . Only sparse information about their impact on acne aetiology is available from the literature: it seems as if these insoluble products obstruct the sebaceous follicle by a mixture of coal tar or oil and keratin products . Males are more commonly affected than females.…”

“…Chloracne, a chronic type of acneiform eruption, is induced by halogenated aromatic hydrocarbons and is a differential diagnosis with acne vulgaris …”

“…Acne has been frequently observed in industry workers after prolonged exposure to certain organic molecules, such as coal tar or crude oil. [81][82][83][84][85] Today, exposure to these molecules has become less common. 86 Only sparse information about their impact on acne aetiology is available from the literature: it seems as if these insoluble products obstruct the sebaceous follicle by a mixture of coal tar or oil and keratin products.…”

Genotoxic changes in peripheral lymphocytes after therapeutic exposure to crude coal tar and ultraviolet radiation

“…37 ), the second pathway includes induction of oxidative stress (oxygendependent mechanism, type II reaction) (ref. 38 ). Both of these pathways induce DNA damage (including strand breaks).…”