What is asthma?
Asthma is an inflammatory lung disease
that causes recurring breathing problems in those affected. During an asthma
attack, the air passages in the lungs narrow or contract — various types of
irritants in the atmosphere can trigger this contraction response. The inner
lining of the bronchi (branches of the airway) also becomes inflamed and swells
and an excess amount of phlegm (mucus) is produced. All of this results in
breathing becoming more difficult.
What causes asthma?
Asthma is most likely a result of genetic
susceptibility. About one-third of all people with asthma share the problem
with another member of their immediate family. The risk of having an asthmatic
child may be six times higher if both parents have a history of asthma than if
just one had the disease.
There has been a dramatic rise in the
incidence of asthma in industrial countries, including Ireland, even though
outdoor air pollutants are decreasing. There are several possible explanations
— for example, children now spend more time indoors and are overexposed to
indoor allergens. Also, modern energy-efficient homes may result in dust mites
being trapped inside them. In addition, more low-birth-weight babies are
surviving and they may be more susceptible to asthma.
However, other respiratory diseases,
sinusitis and ear infections are also increasing, which suggests that airborne
or environmental factors may indeed be involved. Allergies may also play a
Who develops asthma?
Asthma is a very common illness, estimated
to affect 5%-10% of adults and 10%-15% of children, and the numbers are rising.
Children who develop asthma usually belong to a group described as ‘atopic’ —
this means that the child has inherited a gene that makes them liable to
An allergic person will develop some kind
of allergic illness if they encounter an allergen that triggers an allergic
response — the allergic illness may be asthma, hay fever or eczema. They mostly
start in childhood, but can sometimes develop later. Many children with asthma
will "grow out of it".
Asthma that begins in adulthood is usually
the intrinsic or non-allergic type, although adults can develop allergic
What triggers an asthma attack?
Any number of factors can trigger an asthma
attack, depending on the person concerned, but the potential triggers can
generally be divided into two groups:
- Non-specific factors — for example, exercise,
cold, smoke, scents and pollution.
- Specific factors — for example, pollen, dust,
animal fur, aspirin, viral or bacterial infections such as the flu or sinus
infections, chemical fumes or other substances used in the workplace.
What are the signs of an asthma attack?
- Difficulty breathing and shortness of
- Tight feeling in the chest
- Wheezing when breathing out
- Coughing, with mucus
- Persistent cough at night (particularly in
How is asthma diagnosed?
Asthma is underdiagnosed for a number of
reasons — the symptoms are very similar to conditions such as emphysema,
bronchitis, and lower respiratory infections, so the diagnosis may be missed.
If the symptoms are mild, with the only
sign a cough at night or following exercise, the sufferer may not suspect
asthma. Your doctor will take your medical history, carry out a thorough
medical examination, and perform lung function tests to confirm the diagnosis.
The peak expiratory flow is the simplest
lung function test and involves blowing air out as hard as possible through a Peak
Flow Meter and recording the peak expiratory flow rate (PEFR). Other tests may
also be performed — for example, spirometry (using an instrument that measures
the air taken into and out of the lungs), chest X-rays, and sometimes blood and
How is asthma treated?
There is no cure for asthma, so the aim of
treatment is to manage the symptoms so that they do not interfere with your
quality of life or seriously threaten your health.
The first step towards achieving long-term
control of asthma is to avoid trigger factors as much as possible. Avoid
exposure to tobacco smoke and people who have colds and ask your doctor for
advice on minimising the effect of dust mites, animal hair and mould in your
Medication is the mainstay of asthma management
in most patients and is used to control inflammation and to relieve symptoms.
The drug treatment chosen will vary from person to person, depending on the
frequency, severity, and particular triggers of each person’s attacks.
There are two groups of
Relievers (Bronchodilators) work to relieve
symptoms and are generally taken by inhaler. Many of the commonly used
relievers come in blue inhaler containers. Short-acting relievers (so-called
because their effect usually lasts for four hours) work by relaxing the smooth
muscle of the airways, thereby easing symptoms and protecting against the type
of asthma triggered by exercise or contact with allergens. Long-acting
relievers (so-called because their effect usually lasts for up to 12 hours) are
usually prescribed for people whose symptoms are not controlled by moderate or
high doses of inhaled steroids and short-acting relievers. If you are using
bronchodilators more than once a day, you should tell your doctor as your
treatment may need to be adjusted or changed. Beta2-agonists, anticholinergics
and theophylline are all types of bronchodilators.
Preventers are anti-inflammatory medications
(commonly, steroids or corticosteroids). Sometimes, the inflammatory component
of asthma may need to be specifically treated and this is commonly undertaken
with inhaled steroids. These “preventers” generally come in brown inhaler
containers. The effects may not be felt immediately, and you must take them for
several weeks before you get the full benefit. Other types of anti-inflammatory
medications may be used for children, especially those under five years of age.
Oral steroid tablets may be prescribed for bad attacks. Steroids are powerful
drugs, but their safety in asthma has been established.
Very often, a combination of Preventers and
Relievers is recommended. Some asthma inhalers now combine both an
anti-inflammatory medication and a bronchodilator, and are used to prevent an
asthma attack in patients whose symptoms are not well-controlled, or who are
already using the two treatments. These combined inhalers are aimed at simplifying
asthma control in these patients.
A new treatment for people with severe
persistent allergic asthma – called a unique humanised monoclonal anti-IgE
antibody – was introduced in Ireland in 2005. It is a highly specialised
treatment, which is given by injection either every two or every four weeks.
Only certain patients are suitable for the treatment and they will need to undergo
some tests before the medication can be prescribed by their doctor.
The treatment works by blocking the action
of the IgE antibody, therefore targeting the underlying mechanism of allergic
asthma. The aim is to prevent the onset or worsening of symptoms.
How do I choose an inhaler device?
There are several different types of
inhaler devices available and it is important to choose one that you find easy
to use, so that your treatment is effective. Your doctor and the asthma nurse
(if available) will advise you in the correct choice for you or your child.
Also known as pressurised metered dose
inhalers (pMDIs), the medication is mixed with a propellant liquid that
evaporates as the aerosol is used. The drug is released when you press the
trigger, you breathe in slowly, hold your breath for 10 seconds and then
These are effectively ‘holding chambers’
attached to the pMDI. You breathe in the medication from the spacer, so they
are particularly useful for young children and elderly people because you don’t
have to worry about aerosol firing/breathing-in co-ordination.
Dry powder inhalers
These devices deliver the drug in dry
powder form rather than as an aerosol-propelled liquid. Many people find them
easier to use than pMDIs, as you don't have to worry about aerosol
These are devices that use pressurised air
to turn a liquid medication into a fine mist for inhalation (if you have ever
received emergency treatment for asthma, you have probably used a nebuliser).
These devices produce a mist of the medication by passing a jet of compressed
air over it. You breathe the mist in through a face mask or a mouthpiece. They
are often recommended for very young children or if you need to take large
doses of reliever medicines.
What can I do?
- Learn to recognise your triggers and avoid them
as much as possible.
- Take all the medication prescribed by your
doctor, even if you feel well.
- Be sure that you know how to use a peak flow
meter and your chosen inhaler device correctly.
- Stay active — swimming is a good form of
exercise for people with asthma. Take your bronchodilator medication before
exercising if exercise is one of your triggers.
- If you smoke, then stop. It is, alas, that
- If any family member of a person with asthma
smokes, they should be strongly encouraged to stop, or at least, to avoid
smoking in the house.
What is the outlook?
Asthma cannot be cured but it can be
managed effectively so that it does not interfere with your lifestyle. It is
vital that you stop smoking and take all the medication prescribed by your
doctor, even if you feel well. While it is a generally well-controlled disease,
this is not to say that it can be taken too lightly. Failure to follow advice
on your asthma medication can lead to extremely serious complications, and in
some extreme cases, death. The old saying that 'an ounce of prevention is worth
a pound of cure' fits asthma management to a tee.