Biological agents causing occupational airborne contact dermatitis

SEPTEMBER/OCTOBER 2010 30 INTRODUCTION Certain workers, particularly in agriculture, are exposed to large quantities of dust during their work. The dust consists of varying amounts of inorganic material, organic substances of plant and animal origin as well as viable and non-viable microorganisms and their by-products (biochemical components, toxins, antigens).1-4 The pathogenic role of dust components in relation to respiratory disease has been well documented.5 Apart from inhalation, these airborne dust particles, which are regarded as hazardous biological agents, also settle on exposed skin and may trigger local infl ammatory reactions, referred to as ‘airborne dermatitis’.6-9 The dermatitis was coined airborne contact dermatitis due to the infl ammatory reaction (either allergic or irritant) of exposed skin areas (in which the causative role of sunlight can be excluded) initiated by airborne agents that settle on the skin.10-11 Airborne causal agents may be protein in nature resulting in protein contact dermatitis. The pathogenesis of protein contact dermatitis is unclear but may involve a type I (IgE mediated) hypersensitivity reaction, type IV (cellmediated delayed) hypersensitivity reaction, and/or a delayed reaction due to IgE-bearing Langerhans’ cells.12 Many occupational practitioners overlook the effects of these agents on exposed workers and it is important to promote awareness of airborne particle deposition as a trigger of local infl ammation. The main purpose of this paper is to explain the role of airborne biological agents in occupational contact dermatitis, to emphasise the challenges regarding the coexistence of non-occupational and PEER REVIEWED ORIGINAL REVIEW