Case study 1: Animal house technician with skin rashes and respiratory symptoms

A 20-year old woman started work as an animal house technician, dealing mainly with rodents. She was given minimal training on commencement of exposure. A few months later she developed symptoms of runny, glazed and gritty eyes (conjunctivitis) and stuffy, itchy and runny nose (rhinitis). She also had wheeze, tight chestedness and shortness of breath (asthma) which improved on spells away from work. She noticed that when she was scratched by the rodents her skin very quickly developed raised red patches (urticaria). Her general practitioner prescribed treatment with bronchodilators, producing slight improvement, but her symptoms persisted. After about one year in employment she experienced an episode of angio-oedema and had serious difficulty with breathing. She was seen in a hospital casualty department and treated with adrenaline and hydrocortisone. However, no specific action in relation to her job was considered. After this episode she did not return to work and eventually resigned her employment.

Arguably, from a medical standpoint the problem was solved. The work related nature of her symptoms had been demonstrated, at least circumstantially - she would no longer work in the animal house and her symptoms would be expected to resolve.

• Was the management of this occupational disease really adequate?
• What problems can you see in the way in which the case was handled and how might these have been resolved?

The assessment in this case was incomplete. In all cases of asthma, questions should be asked about possible provoking causes, including occupational factors. If such factors are suspected, frequent systematic measurements of peak flow rate, spanning a few weeks at work and off work, should be made.

The management of the patient was not completely satisfactory. As the symptoms persisted in spite of treatment, further investigation should have taken place. Usually in such an example referral for a second opinion is advisable; this might have been to a specialist Occupational Physician such as, in Britain, the local Employment Medical Advisor of the Health and Safety Executive.

There had been no attempt to prevent manage the overall problem. Workplace exposure had not been properly assessed nor adequately controlled as is required by Health and Safety Law. Although the patient’s symptoms were abolished, her social well-being in as much as she was then unemployed was still harmed. Moreover, the workplace problem persisted and other people in the animal house remained at risk. This important preventative aspect of the case can only be addressed by an assessment of the workplace and it is here that the advice of a specialist is particularly important. After a full assessment, steps to reduce the risks could have included:

• Appropriate education of employees and managers.
• Better segregation and enclosure of the animals.
• Effective local exhaust ventilation.
• Possibly personal protection (to supplement the above - NOT as a substitute).
• Systematic Health Surveillance.

The patient lost her job, without financial compensation. In Britain and many other countries, there are systems for industrial injury benefits to be paid to people suffering from certain occupational diseases. The patient in this case should have been advised that her condition was one that would, in the UK, be recognised for such benefits were she to apply to the Department of Social Security.

The disease was not initially reported to the statutory authorities. The law varies between countries, but in Britain the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR) put the responsibility on employers to report any of a long list of occupational diseases. The doctor who makes the diagnosis should inform the employer, with the patient's consent or, if this is not freely given, consult with an Employment Medical Advisor in the Health and Safety Executive directly. The regulatory authority is then in a position to take appropriate action. If this step is taken, it is often possible for the workplace risk to be reduced and sometimes for the patient to return to work.

Angio-oedema is a very rare emergency in an industrial context. Nevertheless, severe anaphylactic reactions could occur, in a small proportion of individuals sensitised to laboratory animal allergens. It is false to assume that this rare but severe event is completely unpredictable. Affected workers often give a history of earlier milder episodes with urticaria and palpebral oedema. These heralds should be heeded. Steps to reduce occupational exposure will reduce the risks.