Occupational asthma

What is occupational asthma?

Occupational asthma is often overlooked and caused by exposure to allergens or sensitising agents at work. Early diagnosis and referral to a Respiratory Physician are vital. Occupational asthma accounts for 5-20% of new adult-onset asthma cases, with rhinitis sometimes preceding it by up to a year.

Occupational asthma develops from workplace exposure to substances like dust or chemicals, sometimes taking weeks or years to appear. It differs from work-aggravated asthma, where existing asthma worsens due to work conditions. Employers must prevent or manage exposure to hazardous substances and provide reasonable adjustments if needed. For more information, please consult the Health & Safety Authority's Guideliens on Occupational Asthma.

Signs of occupational asthma

• Symptoms worsen during the workweek or right after work
• Sleep is disrupted due to increased symptoms during the week
• Symptoms improve when away from work (weekends or holidays)
• New hay fever, cough, or wheeze, especially in non-smokers, may indicate occupational asthma.

Who is at risk of occupational asthma?

Hundreds of substances can cause occupational asthma, including:

• Chemicals called Isocyanates (found in polyurethane (PU) paints, foams, varnishes, glues and flooring)
• Flour dust
• Latex
• Grain/poultry dust
• Rosin fumes (from solder flux)
• Metalworking/welding fumes
• Wood dust
• Animal-related dusts (fur, feathers, etc.)

High-risk workers include:

• Paint sprayers
• Bakers
• Healthcare workers
• Chemical workers
• Animal handlers
• Welders
• Metalworkers
• Food processors
• Timber workers
• Nail technicians
• Agricultural workers

How is occupational asthma diagnosed?

Visit your GP if you have symptoms. They’ll ask:

• Did symptoms start in adulthood?
• Do symptoms improve when away from work?
• Do symptoms worsen after work or overnight?

They will also ask you about your current job and jobs you have done previously. If your GP thinks you have occupational asthma, they will refer you to a specialist.

You will have tests performed to confirm diagnosis, such tests may include;

Peak flow test - You will need to do this at least four times a day for at least three weeks and keep a diary of the results. Your doctor may also ask you to record what times you do certain tasks at work or are exposed to certain substances.

You may have blood tests or skin prick tests carried out. These tests will determine if you have an allergy to something you are exposed to at work.

Some people also have challenge tests. A challenge test involves exposing you to the substance or substances that may be causing the symptoms.

How is occupational asthma treated?

Treatment is the same as regular asthma, but avoiding the trigger is crucial. About 30% recover fully if they avoid exposure.

Employer Responsibilities

The employer must ensure a safe working environment where exposure to substances which can cause asthma is prevented or controlled. The employer should have or provide the following:

• An up to date Safety Statement
• A Risk Assessment
• Adequate control measures
• Employee information
• Appropriate health surveillance