Agents triggering airway hyperactivity

In response to a number of stimuli and in the apparent absence of an allergic IgE mediated response, individuals with asthma may experience bronchoconstriction and airflow limitation in response to stimuli such as:

• upper respiratory tract infection
  • predominantly viral
  • more common in children than in adults and during winter than in summer
• smoking
• occupational sensitisers - for example
  • colophony fumes in the soldering and the electronics industry
  • chemicals - isocyanates in industrial coatings, platinum salts, aluminium (1)
• psychological factors such as stress and emotion
• exercise
• cold air and exercise
• drugs - such as beta blockers, aspirin and NSAIDs, angiotensin-converting enzyme inhibitors (ACEI’s) (1)
  • ACEIs - symptoms of airway obstruction in relation to treatment with angiotensin converting enzyme inhibitors seem to be a rare but potentially serious reaction generally occurring within the first few weeks of treatment (2)

Variation in symptoms throughout the working week may provide a clue to an occupational allergen. A seasonal pattern implies seasonal allergen exposure.

Reference:

• (1) John Rees, Dipak Kanabar, Shriti Pattani. ABC of Asthma, 6th Edition
• (2) Lunde H et al. Dyspnoea, asthma, and bronchospasm in relation to treatment with angiotensin converting enzyme inhibitors. BMJ. 1994 Jan 1;308(6920):18-21.