Nelson Textbook of Pediatrics 22nd Edition | Occupational asthma: high molecular weight antigens (animal proteins, flour, enzymes, latex) โ IgE-mediated; low molecular weight (isocyanates, metals, wood dust) โ non-IgE (hapten). Irritant-induced asthma: reactive airways dysfunction syndrome (RADS) after single high-level exposure. Diagnosis: serial PEF monitoring at work (improves on days off), methacholine challenge, specific IgE. Treatment: exposure avoidance (complete removal from workplace), inhaled corticosteroids. Prevention: workplace controls, respiratory protective equipment.
๐ paeds.online โ Pakistan's Pediatric Platform| Agent Type | Examples | Mechanism |
|---|---|---|
| High molecular weight (HMW) | Animal proteins (lab animals, birds), flour/grain, enzymes (Bacillus subtilis in detergents), latex | IgE-mediated (Type I hypersensitivity) |
| Low molecular weight (LMW) | Diisocyanates (paints, foams), metals (platinum, chromium, nickel), wood dust (western red cedar), anhydrides, drugs (ฮฒ-lactams) | Non-IgE (hapten, may be Type IV or irritant) |
| Irritant-induced asthma (RADS) | Chlorine gas, smoke, acetic acid, ammonia, diisocyanates (high concentration) | Single high-level exposure โ airway inflammation, non-immunologic |