Allergic Occupational Asthma


Allergic Occupational Asthma, Latency-associated Occupational Asthma

  • Pathophysiology
  1. Sensitization to specific workplace chemical
  2. Initial response delayed from weeks to years
  • Causes
  • High Molecular Weight Substance Exposure (>1 kilodalton)
  1. Background
    1. Type I Hypersensitivity Reaction (IgE mediated)
    2. Symptoms within 20 minutes of exposure
    3. Resolves gradually within 1 to 2 hours
  2. Causes
    1. Flours or grain dust (Bakers, farmers, grain process)
    2. Insects (silk-processing, research)
    3. Seafood or marine organisms (seafood processors)
    4. Animal dander (animal handlers)
    5. Enzymes (Detergents, food industry, blood process)
    6. Gums or latex (manufacturing, health care)
  • Causes
  • Low Molecular Weight Substance Exposure (<1 kilodalton)
  1. Background
    1. Allergic response of unclear mechanism
    2. Symptoms occur 3-4 hours after exposure
    3. Results in severe airway inflammation
  2. Causes
    1. Colophony: Abietic acid (electronic industry)
    2. Plicatic acid: Western red cedar dust (woodwork)
    3. Metals: Chromium, Platinum, Nickel (Refinery)
    4. Dyes (Textile industry)
    5. Persulfate salts, a bleaching agent (Hair dressing)
    6. Anhydrides: Trimellitic, Phthalic (Plastics)
    7. Acrylates such as Methacrylate (Adhesive workers)
    8. Glutaraldehyde or Formaldehyde (Health care)
    9. Pharmaceuticals (Pharmaceutical Industry)
    10. Polyurethane (paints and adhesives)
    11. Diisocyanate: Toluene, Diphenylmethane, Hexamethylene
      1. Used in plastic and Rubber
      2. Used to create foam insulation
      3. Used to harden polyurethan paints (auto, boat)
  • Differential Diagnosis
  1. Intrinsic Asthma
    1. Nonspecific triggers for airway hyperresponsiveness
  2. Reactive Airway Dysfunction Syndrome
    1. Follows very high irritant exposure