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A substance that causes an allergic reaction in the body. It is usually an animal or plant protein. Examples include animal, plant, insect, fungal, enzymes and food proteins, rat proteins (especially from rat urine), pollens (from trees, grass, weeds), mites and cockroach proteins, mould spores, detergent enzymes, wheat, powdered milk and other food dusts.

These substances are also called High Molecular Weight sensitizers. These substances can cause or trigger asthma by causing development of certain antibodies, IgE antibodies, that can link specifically to the allergen and cause an allergic response. These antibodies are formed only in a small proportion of people who are exposed to the allergen.


A medical doctor who specializes in the treatment of allergic disease.

Corticosteroid inhaler

Inhaled corticosteroid, is a type of asthma medication also called “preventer” or “controller”, or “inhaled steroid”. Inhaled corticosteroids reduce inflammation in the lungs and thereby open the airways to keep asthma controlled and prevent attacks. They are not the same as the anabolic steroids taken illegally by athletes.

While "relievers" help you treat the symptoms of asthma, controller medications help to treat the underlying inflammation of the airways in a person with asthma. When you start taking controller medications, you may not notice a difference right away. It may take a few weeks before the inflammation in your airways is reduced. Even if you do not feel better right away, do not stop taking your controller medication unless your doctor tells you to.   Examples of corticosteroids include Pulmicort, Flovent, Alvesco, QVAR,  Asmanex and Arnuity.  Combination medications, such as Advair, Symbicort, Zenhale and Breo contain a corticosteroid and long-acting bronchodilator.

Controller (Preventer)

Asthma medications used daily to prevent and control asthma symptoms. Controllers or Preventers are also called Inhaled Corticosteroids or inhaled steroids. They reduce inflammation (swelling, redness, mucus) in the lungs and thereby open the airways to keep asthma controlled and prevent 'attacks'. For more details see corticosteroid inhaler


Also called 'dermatitis'. A skin condition where certain areas of the skin get inflamed and itchy and sores develop. This skin condition cannot be passed on to other people. It can be allergic (atopic) or non-allergic.

Hay fever

Allergies in the nose and eyes that occur due to seasonal allergens (pollens from trees, grass, weeds); also referred to as seasonal allergic rhinitis.

High-molecular weight agent

Work exposure substances that can cause occupational asthma to happen are called occupational sensitizers. Two examples of occupational sensitizers include "high-molecular weight" and "low-molecular weight" agents that can act as sensitizers. Examples of "high-molecular weight" agents include proteins from animals, plants, foods, insects, fish, enzymes and moulds. High-molecular weight agents/sensitizers are also called allergens. For more details see Allergens.


A substance that causes irritation. For work-related asthma, an irritant is a substance that does not cause an allergic reaction or sensitization but temporarily worsens asthma symptoms. Examples are smoke, fumes, and dusts.

An irritant usually causes a worsening of asthma symptoms. Rarely, a very high exposure to an irritant can cause Irritant-induced Occupational Asthma.

Inhaled Medications

Medicine a person breathes in. It goes directly to the airways.

Long-Acting Bronchodilators 

Long-Acting Bronchodilators, such as Serevent, Foradil, Onbrez, Oxeze, and Serevent take longer to work but their effect on the lungs last longer than short-acting relievers. This provides longer periods of relief from Asthma symptoms. Long-acting bronchodilators medications should always be used together with a corticosteroid.   Everyone with asthma should have a short acting reliever inhaler.   

Low-molecular weight agent

Work exposures that can cause occupational asthma to happen are called occupational sensitizers. Two examples of occupational sensitizers include "high-molecular weight" and "low-molecular weight" agents that can act as sensitizers. "Low molecular weight" agents include different chemicals such as Isocyanates, Platinum, Nickel sulfate, chromium, etc.

Occupational Asthma

Occupational asthma is a type of work-related asthma. When a person, who did not previously have asthma, develops asthma due to exposures in the work environment, it is referred to as Occupational Asthma (OA).

Occupational sensitizers

Work exposures that can cause occupational asthma to happen are called occupational sensitizers. These are often materials that can cause allergic types of reactions in the nose or eyes as well (e.g. runny and itchy eyes and nose, sneezing)

Peak Flow Meter

A portable, hand-held device that measures how fast a person can exhale in litres per minute (lpm). It can be useful for monitoring a person's asthma.


A common term for inhalers used to treat asthma.

Reliever inhaler

Everyone with asthma should have a reliever inhaler.  Short-acting relievers inhalers are usually blue. These reliever medicines are taken immediately to relieve asthma symptoms. They quickly relax the muscles surrounding the narrowed airways. This allows the airways to open wider, making it easier to breathe again.  Reliever inhalers do not reduce inflammation in the airways. To treat inflammation, you will need to take a controller or preventer medication.  Examples of quick-acting reliever medications include Ventolin, Bricanyl and Airomir.


A medical doctor specializing in the diagnosis and treatment of lung diseases.


An allergen or a chemical that can cause asthma. Sensitizers include High Molecular Weight Sensitizers (allergens) and also Low Molecular Weight Sensitizers (chemicals that can cause asthma in a way similar to an allergic response, in a small proportion of people who are exposed to the chemical. Examples include isocyanates (as in spray paints and reactive glues), acrylic compounds, epoxy chemicals and platinum salts.


A tube-like device used to increase the  the disposition of medication in the lungs as well as the ease of administering aerosolized medication from a metered-dose inhaler (MDI).


An asthma trigger is anything that makes asthma worse   resulting in coughing, wheezing, trouble breathing, etc). Some common triggers include colds, smoke, cold air, exercise, and certain things that cause allergic reactions, such as dust mites or pollen. Triggers can vary from person to person and from season to season. They also can change as a person grows older.

Viral infections

Most respiratory infections are caused by viruses (i.e. viral infections) rather than bacteria. Viral infections can cause symptoms such as feeling unwell, fever, and chills. Viral infections cannot be cured by antibiotics. Viral infections often affect many different parts of the body or more than one body system at the same time (i.e. a runny nose, sinus congestion, cough, body aches etc.)

Work-Related Asthma (WRA)

When some exposures in your workplace exacerbate or even cause (new) asthma in you, the condition is referred to as work-related asthma. There are two types of work-related asthma:

  1. Work-Exacerbated Asthma (WEA) and
  2. Occupational Asthma (OA).

Work-Exacerbated Asthma (WEA)

Work-exacerbated asthma is a type of work-related asthma. When your existing asthma gets worse due to exposures and conditions in your work environments, it is referred to as work-exacerbated asthma (WEA).This could be a short-term worsening of asthma symptoms if you are exposed to something at work that aggravates your asthma, like smoke, dust, chemicals or fumes, in the same way that these exposures could trigger your asthma outside of the workplace.


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