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GP and Practice nurse guide to Occupational Asthma

Patients may unknowingly have a health problem that is caused or made worse by their work. Also, few workers have access to an occupational health physician so for many patients the first point of call relating to a work-related health problem will be clinicians working in primary care. This makes early case finding an important role for primary care clinicians.

Important facts

  • About 1 in 6 cases of adult-onset asthma are caused by exposures to substances in the workplace.
  • Rhinitis often accompanies and may precede the onset of occupational asthma usually by about a year; so, it can be an early indicator of sensitisation.
  • For most causes, the risk of developing occupational asthma is greatest during the early years of exposure; however, processes and controls may change at work so occupational asthma may develop at any stage of a person’s career.
  • Prognosis is best in patients whose occupational asthma is diagnosed early; who have relatively normal lung function and who avoid further exposure to the causative agent early in the course of the disease.

What to do when an adult patient presents with new or worsening symptoms

Consider the possibility of an occupational cause in all adult patients who present to primary care with either new-onset or worsening asthma and/or rhinitis symptoms.

  • Ask each adult presenting with new or worsening symptoms of asthma or rhinitis:
    • When did the symptoms start?
    • Do your symptoms improve when away from work (holidays and weekends)?
    • What is your job and what substances do you work with?
    • Do you have regular health surveillance at work (respiratory questionnaires and lung function tests)?
  • Consider performing objective tests such as spirometry. If you can arrange serial peak flow measurements ask the patient to perform the test at least four times a day, for at least three weeks including consecutive days at and away from work.

What to do when you suspect that a patient might have work-related symptoms

  • Advise the patient to speak to their employer.
  • If you are certifying the patient not fit for work you may tick the box “amended duties”. Consider adding a statement “must avoid exposure to substances known to cause asthma pending employer’s risk assessment and further investigation”
  • Ask the patient if they have access to an occupational health physician; if they do advise them to contact their occupational health service for assessment and advice.
  • If the patient’s employer does not provide access an occupational physician referral to a physician with expertise in occupational asthma or rhinitis may be appropriate, especially if they work in a high-risk job.

Making a diagnosis of occupational asthma

The diagnosis of occupational asthma needs to be made by physicians with relevant expertise and be supported by objective tests (spirometry, serial peak flow measurements, immunological tests) and not simply on the basis of a compatible history because of the potential implications for future employment.

The management of occupational asthma

  • The clinical management of occupational asthma is the same irrespective of the cause and should follow published clinical guidelines.
  • Occupational management and avoidance of further exposure is particularly important. This may have implications for a patient’s job and earnings, so the employer should arrange a referral to a specialist occupational physician for assessment and advice about occupational management. (TEXT HERE RE: SOM MEMBER LIST)

Compiled by Dr Paul J Nicholson OBE, a former GP and specialist in occupational medicine.

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SOM membership is open to general practitioners and nurse/advisor/practitioners registered with the Nursing & Midwifery Council.