• airborne contact dermatitis;
  • coal dust;
  • occupational;
  • patch test

Airborne contact dermatitis is a common problem in occupational dermatology (1). Various kinds of dust particles, vapours and gasses present in the work environment can be implicated. Coal is a fossil fuel extracted from the ground, composed primarily of carbon along with assorted other elements and is primarily used a solid fuel to produce electricity and heat through combustion. According to the literature, the incidence of allergic contact dermatitis to coal or its products is small.

A 52-year-old man employed in a power station for more than 10 years, presented a 6-month history of a symmetrical eczematous eruption in his thighs, backside, trunk and arms, being more intense on flexural areas. He had no personal and familial history of atopy. Control measures taken in the factory were respiratory protection and protective clothing (gloves and safety glasses with side shields). He also used long cotton underwear, but he referred the coal dust passed under protective clothes because of his skin being black when he was taking them off. There was nobody else in his job with his symptoms and the lesions reduced on vacations and worsened after returning to work.

Because of the clinical features, the distribution of the lesions and the work exposure, we suspected an occupational airborne allergic contact dermatitis. Skin biopsy was taken showing light surface dermatitis and lymphocytic perivascular infiltrate with orthokeratosis compatible with contact dermatitis. He started to be on sick leave and he was successfully treated with systemic and topical corticosteroids and oral antihistamines for 3 weeks.

Patch tests were carried out with the GEIDC standard series (; accessed 4 July 2007) and coal dust (1% petrolatum), becoming positive for coal dust at 96 h (+++). Coal dust was patch tested in 20 controls with negative results.

Coal tar has been described as a contact allergen in topical preparations in the treatment of psoriasis, after a long-standing skin contact (2) and only after a short time on a small skin area (3). We have found a report of contact dermatitis on hands because of newsprint ink (4) whose composition was carbon black. However, airborne occupational allergic contact dermatitis by coal dust is not frequent. There is one case in the literature (5) in a chimney sweep and in certain occupations; soot should not be considered as an irritant. The importance of anamnesis data, analysis of symptoms and signs are needed to reach a correct conclusion (6) and patch testing is invaluable for the investigation of most forms of occupational contact dermatitis (7).


  1. Top of page
  2. References