Module 4: Occupational Allergy - Lecture (Continued)

6. COMMON OCCUPATIONAL ALLERGIC DISEASES:

6.1 Hypersensitivity pneumonitis (extrinsic allergic alveolitis):

Type III and Type IV immune mediated hypersensitivity reaction (Table I).

Table I: Selected causes of occupational hypersensitivity pneumonitis
Source of antigen Antigen Disease
Mouldy hay, straw, compost Thermoactinomycetes spp., Micropolyspora faeni Farmers' Lung
Mouldy bagasse Thermoactinomycetes spp., Micropolyspora faeni Bagassosis
Spores, mouldy compost Thermoactinomycetes sacchari Mushroom workers' lung
Mouldy maltings Aspergillus spp. Malt workers' lung
Damp, stored bark Aspergillus spp. Bark strippers' lung
Cheese mould Penicillium casei Cheese workers' lung
Damp wood Rhizopus spp. Sawmill workers' lung
Air conditioning systems Thermoactinomycetes spp., Acanthamoeba castellani, Naelgeria gruberi Ventilation pneumonitis
Bird blooms, droppings Avian proteins Bird breeders disease
Polyurethane foam Toluene diisocyanate Hypersensitivity pneumonitis
Spray paints Diphenylmethane diisocyanate Hypersensitivity pneumonitis
Therapeutic drugs Amiodarone, gold, procarbazine, minocycline Hypersensitivity pneumonitis
6.2 Rhinitis, conjunctivitis, urticaria (angioedema, anaphylaxis):

Type 1 immune mediated hypersesitivity reaction (Table II).

Table II: Some common causes of occupational allergic rhinitis and associated occupations
Agent Associated occupations
Animal products Veterinarians and their helpers, farm workers, poultry workers, laboratory animal technicians
Flour Bakers, millers, granary workers, dockworkers
Wood dust Flooring specialists, furniture makers, carpenters, lumberjacks
Latex Medical and paramedical workers, hairdressers, domestic workers, food industry workers
Washing powder enzymes Domestic workers, laundry workers, production workers
6.3 Occupational asthma:

Type 1 immune mediated hypersensitivity reaction (Table III).

Table III: Some common causes of occupational asthmaa and associated occupations
Agent Associated occupations
Allergenic proteinsb (dander, urinary proteins, milk, flour, detergents, eggs, storage mites) Veterinarians and their helpers, poultry workers, laboratory animal technicians, farm workers, dairymen, bakers, millers, granary workers, domestic workers, warehouse workers
Wood dusts Sawmill workers, sanders, cabinet makers, lumberjacks
Latexb Medical and paramedical workers, hairdressers, domestic workers, food industry workers
Isocyanatesb Workers exposed to polyurethanes, coatings, adhesives, plastic fibres
Epoxy resins Workers who use reinforced plastics, adhesives, moulding resins, surface coatings
Metallic saltsb (of nickel, chromium, vanadium, platinum) Mainly refinery workers
(a) Since the respiratory tract is the final common pathway for all inhaled pollutants, many causative allergens are the same as for chronic allergic rhinitis.
(b) Currently, the most common reported causes of occupational asthma in South Africa are latex (28%), flour/grain (12.7%), platinum salts (10.2 %) and isocyanates (10.2%).
6.4 Allergic contact dermatitis:

Type IV immune mediated hypersensitivity reaction (Table IV).

Table IV: Some common causes of occupational allergic dermatitis and associated high-risk occupations
Agent Associated occupations
Epoxy resins Workers who use reinforced plastics, adhesives, moulding resins, coatings
Fragrances Beauticians, domestic workers, hairdressers and anyone else using soaps, creams, detergents, etc.
Chromate Construction workers, tilers, plasterers and anyone working with cement and cement products.
Nickel (found in almost all metal products) Constant exposure to metal levers, handles, etc.
Rubber chemicals Workers exposed to anything containing rubber. Also found in personal protective equipment
Dyes Fabric, printing and painting industries
Plants (e.g. Rhus, nettle) Gardeners, horticulturists, nurserymen
Biocides Domestic workers and all workers using cleaning agents

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