Diagnosis, management and prevention of occupational asthma

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This concise guideline, aimed at physicians, summarises a full guideline published in 2010 by the British Occupational Health Research Foundation and aims to help reduce the severity of individual cases of occupational asthma by promoting earlier, accurate identification and better management.

Key recommendations

  • An early and accurate diagnosis of occupational asthma offers the unusual prospect of a ‘cure’ for the disease. Conversely, inaccurate diagnoses can either hamper symptom control and risk a poor prognosis (ie false negative diagnosis) or lead to unnecessary economic hardship and a failure to improve (ie false positive diagnosis).
  • Effective management involves timely intervention and taking appropriate actions to protect patients with occupational asthma from further exposure to its causes in the workplace.
  • Given that there might be significant consequences for the patient’s employment, informed consent should be written when communicating with a patient’s employer. Employers can protect the patient by several means, ranging from engineering controls (which will protect other workers) to redeployment to a job free from exposure. Once sensitised, a patient’s symptoms might be incited by exposure to extremely low concentrations of a respiratory sensitiser. Hence, respiratory protective equipment (RPE), such as air-fed helmets, might improve or prevent symptoms in some, but not all, patients who continue to be exposed to the causative agent. RPE offers protection only insofar as the correct type is selected, it is worn when appropriate, there is a good fit on the face and proper procedures are followed for its removal, storage and maintenance.
  • Generally, occupational asthma has a poor prognosis, with approximately two-thirds of workers never achieving full symptomatic recovery and approximately three-quarters having persistent non-specific bronchial hyper-responsiveness. Approximately one-third of workers with occupational asthma are unemployed up to 6 years after diagnosis. Specialist hospital and, where available, specialist occupational health care might improve these outcomes.
  • Occupational asthma is a prescribed disease for the purpose of Industrial Injuries Disablement Benefit.
  • If the employer failed to take adequate precautions to prevent harm, the patient might be entitled to make a civil claim for compensation for personal injury. Occupational asthma is reportable under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR), whereby employers have a statutory duty to report cases to the HSE.