Occupational asthma is a disorder of the lungs that is characterised by narrowing of the airways which causes shortness of breath.
The narrowing is caused by reversible inflammation of the airways. There are two main types of occupational asthma depending on what causes the asthma.
One type is caused by an agent which stimulates the immune system of the body to trigger asthma (immune-mediated).
The other type of occupational asthma occurs when an agent irritates the airways directly (irritant-induced).
Causes of Occupational Asthma
Occupational asthma is caused by inhalation of particular workplace substances that cause excessive reaction of the airways.
Examples of exposure to various substances in the workplace that has caused occupational asthma are the following:
- Chemicals used in factories to make varnishes, paints, adhesives, soldering resin and laminates. Other examples of chemicals are those used in making insulation, foam mattresses and packaging material.
- Respiratory irritants such as smoke, dust, wood chippings, sulfur dioxide and chlorine gas.
- Animal substances such as the proteins found in fur, dander, scales and saliva.
- Enzymes used in flour conditioners and detergents.
- Plant substances including the proteins found in cotton, cereals, flax, wheat, papain and natural rubber latex.
- Metals especially chromium, platinum and nickel sulfate
Occupational asthma symptoms start to show when the lungs become irritated or inflamed after inhalation of the above workplace substances. Such inflammation makes breathing difficult and may actually be triggered by an allergic response to a particular substance.
Symptoms and Signs of Occupational Asthma
General symptoms of asthma are shortness of breath, chest tightness and wheezing weeks or even years after exposure to workplace substances.
A runny nose (rhinorrhea) and inflammation around the linings of the eyes (conjunctivitis) may occur before experiencing shortness of breath.
If no immediate medical action is taken, occupational asthma patients may tend to develop constant symptoms.
Coughs with or without production of sputum (phlegm) may also be present. Most patients have worse symptoms at their workplaces and feel better away from work.
The latency period between the onset of symptoms and the time of the workplace exposure is highly variable.
Low-molecular weight workplace substances that cause occupational asthma exhibit symptoms within a shorter latency period than the high-molecular weight substances.
Diagnosis and Treatment of Occupational Asthma
The diagnosis of occupational asthma is similar to that of other types of asthma.
Your doctor will however seek to identify whether there is a workplace substance that is the cause of your symptoms.
Treatment is done by asthma specialists including allergists and pulmonologists.
Occupational asthma diagnosis is confirmed with lung function tests and allergy skin prick tests.
Your doctor may order X-rays, blood tests and other tests in order to rule out other causes other than occupational asthma.
Lung function tests are carried out in the following ways:
A commonly preferred test for asthma diagnosis is spirometry mainly because it’s a noninvasive test.
The test takes about 10-15 minutes during which you are required to take deep breaths and exhale forcefully a hose.
The hose is connected to a machine called a spirometer that measures certain key measurements depending on your age and gender.
Peak flow measurement
For the peak flow measurement, you will be required to carry hand-held device that is small. The device (peak flow meter) measures how quickly you force air out of your lungs.
Treatment of occupational asthma is aimed at preventing the symptoms and stopping an asthma attack in progress.
Medication can include inhaled medicines known as bronchodilators.
Personal Protective Equipment
Personal protective equipment protects you against safety and health risks at work. Respiratory protective equipment is essential in preventing occupational asthma when there are risks of exposure in the workplace. Workplaces that have oxygen-deficient atmospheres present a higher requirement for protection against occupational asthma.
Safety, Health and Welfare Obligations at Work
All employers are legally required to ensure the welfare, safety and health of their employees at work. The employers should design, provide and maintain safe means of conducting work without causing any health risks to employees.
In case of any potential health risks to occupational asthma, employers must provide reasonable prevention equipment to their employees. Plans and procedures should also be prepared and revised on how to handle emergency occupational asthma attacks.
Risk Assessment and Safety Statement
Every employer is required to prepare a written statement of the risk assessment undertaken at the workplace. Safety statements prepared by employers should be given to employees.
Safety statements should explain the hazards and risks assessed, explain the plans/procedures, preventative measures taken by the employer for safety protection.
Occupational asthma is a work-related lung disorder that is caused by inhaling particular workplace substances.
Employers are legally required to provide their employees with protective and preventative measures against occupational asthma.
Frequently Asked Questions
The first question to ask is – is the cause of the asthma something in the workplace ?.
If the answer is in the affirmative, then what is the specific cause of the asthma ? ie was it dust exposure in the workplace due to a wood chipping machine that was defective, or was it due to an inappropriate system of work, such as not providing masks ? as an example.
A diagnosis after the doctor has reviewed the persons medical history and circumstances at work should provide some clarity on this matter. If the person has seen a respiratory physician, what was the physicians opinion etc.
Medical evidence will be required from an appropriate doctor who has reviewed the persons medical history, facts, made a diagnosis and who has explained what is the cause of the asthma. Some asthmas are allergy based, some just happen in adulthood, and are occupational in origin.
Causation must be proved in these types of legal cases. In simple terms – it must be proved that the negligence as a consequence of the duty breach caused the injury.
Case Assessment Advice
If you are suffering from asthma caused by your work duties, you can contact us by telephone or email and we will have an initial meeting with you to explore the facts and furnish a case opinion to you.