Systemic contact dermatitis: Occupational dermatitis caused by inhalation of metal dust (2 reports)

Introduction: Two workers from metal processing factories developed severe generalised contact dermatitis. Neither worker was actually working with the metals. Linking workplace exposure with the clinical presentation of dermatitis is challenging particularly when the exposure is not through direct contact.

Objectives: Establish if occupationally related systemic contact dermatitis was related to metal exposure in the workplace.

Methods: A clinical assessment was conducted of two workers from different companies who presented at the NIOH skin disease clinic. Case 1 worked at a steel cutting factory whose condition improved when away from work. Case 2 worked at a chrome plating factory as an electrician. His dermatitis condition improved when away from work as well. Patch tests and skin prick testing (SPT) was performed on both workers. The level of exposure to the relevant metals occurring in the workplace was obtained from the respective companies.

Results: Case 1 worked at a steel cutting factory and developed severe dermatitis in a symmetrical flexural distribution (atopic dermatitis). His hands, face and folds of the neck were not affected. The patch test was positive (1+) to nickel sulphate whilst the SPT was negative. The ambient nickel levels (≤0.008mg/m3) at the workplace were lower than the South African (SA) recommended maximum exposure level.

Case 2 was an electrician exposed to chrome twice daily when briefly walking through the chrome plating section of the factory. He had severe dermatitis on his inner arms and his legs which spread over his body as erythrodermia. Atopic dermatitis was questionable. Both the patch tests and SPT were positive to potassium dichromate. Hexavalent chromium in air samples (<0.01mg/m3) at work was lower than the SA recommended maximum exposure level.

Discussion: The source of exposure to the allergens was the surrounding air in both cases. The inhalation of the metal salts caused systemic contact dermatitis. Contact dermatitis occurred even though the level of nickel and hexavalent chromate in the two respective factories was below the SA recommended safety limits