skip to main content

Isocyanate-induced occupational asthma — SCE Respiratory MCQ

Instant feedback + full explanation. One question, done properly.

HardAsthmaIsocyanate-induced occupational asthmaSCE Respiratory

A paint sprayer has cough and wheeze that improve away from work. Serial peak flow confirms work-related variability, baseline spirometry is normal and specific IgE to isocyanates is negative. Which interpretation is most appropriate?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — Work-related asthma from non-IgE isocyanate sensitisation

The best answer is “Work-related asthma from non-IgE isocyanate sensitisation”. A negative specific-IgE result does not exclude isocyanate occupational asthma because non-IgE mechanisms occur; the reproducible work-related peak-flow pattern is the decisive evidence and should prompt specialist occupational assessment and exposure control. The remaining choices—“Non-occupational eosinophilic asthma unrelated to workplace exposure”, “Inducible laryngeal obstruction confined to the workplace”, “Hypersensitivity pneumonitis caused by isocyanate aerosol”, “COPD caused by cumulative occupational vapour exposure”—are credible in related respiratory presentations, but each addresses a different diagnostic, staging or management decision and does not fit the decisive findings and pathway position in this stem.

Reference: Health and Safety Executive: occupational asthma: https://www.hse.gov.uk/asthma/