• is one of the most common respiratory complaints in the world to-day
• affects one in ten children and one in twenty adults
• can occur for the first time at any age even in adulthood, although it usually begins before the age of five years. Half of children affected will outgrow it during their teenage years but it usually persists if contracted in adulthood
• tends to run in families as do similar related allergic conditions like hay fever, eczema and urticaria
• cannot as yet be cured but if kept under control, those affected will be able to live normal lives enjoying full involvement in sport and all other activities.

The greatest tragedy of asthma is that it is sometimes not recognised and treated, in which case the patient undergoes needless suffering.

What happens to the lungs in asthma?

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Asthma affects the breathing pipes or tubes called airways or bronchi. When we breathe in, air passes through the voice-box and down the wind-pipe (called the trachea). The wind-pipe branches into the two main bronchi which take air into the two lungs. These bronchi then divide further and further becoming smaller and smaller as they take air deeper into the lungs to the point where oxygen passes into the blood-stream and carbon dioxide is released to be breathed out.

The walls of the bronchi can be divided into 4 layers:

• the very thin smooth inner lining is called the mucosa
• the layer just deep to this contains mucus secreting glands

• the third layer is cartilage which acts like scaffolding holding these tubes open
• the outer layer is a muscle layer

Asthma is characterised by narrowing of the bronchi caused by:

• swelling of the mucosa
• increased sticky mucus or secretions lying in the airways produced by the mucus glands. This swelling and increased secretions are called inflammation.
• muscles going into spasm. Spasm occurs only when there is inflammation.

When the bronchi become to narrow or partially obstructed from inflammation and spasm, the typical symptoms of asthma will develop. These symptoms are:

• cough which often occurs more frequently at night and with activity, can be dry or mucousy and is persistent
• wheezing which is a whistling noise in the chest
• tightness of the chest with breathing difficulty
• shortness of breath especially after exercise.

The exact cause of the asthmatic process is not well understood but it is thought to be triggered, off by an allergy or when the lungs are irritated by something in the air.

What starts an asthma attack?

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Allergies Asthma attacks are most commonly triggered by allergies to airborne particles of house dust mites, grass or tree pollen, fungal spores and skinflakes from furry animals such as cats and dogs. Certain foods and additives can also trigger off asthma when eaten.

 

Pollution

Pollution in the environment, especially cigarette smoke, car exhaust fumes and certain chemical gases can aggravate an asthma attack. Even children will be affected if they passively breathe their parents cigarette smoke into their lungs.

 

Sport and exercise

Sport and exercise, particularly in cold weather, can set off an asthma attack. However with the correct treatment asthma can be well controlled so asthmatics should not avoid sport or exercise, in fact about 10% of Olympic athletes have asthma.

 

A viral cold or the flu

A viral cold or the flu can make asthma symptoms temporarily worse and this effect may last for up to six weeks after the illness.

Emotions

Emotions such as excitement, anger, fear and laughter can all aggravate asthma, but
“nerves” are not responsible for causing asthma.

 

Drugs

Certain commonly used medicines such as aspirin and other anti-inflammatory tablets may trigger asthma. Be cautious with using “Beta Blocker” blood pressure tablets and eye-drops for glaucoma as they can also trigger asthma in adult life.

How is asthma treated?

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There is at present no known cure for asthma. Many children outgrow their asthma and other individuals may improve dramatically with institution of simple environmental changes. With the right treatment most asthmatics will lead completely normal lives. The aim of treatment should be to make the lungs and breathing tubes as normal as possible so that there are minimal symptoms and as little disruption to ordinary life as possible. Asthma sufferers should be encouraged to try to avoid the things that trigger their asthma and most importantly, to
take regular medication. Different people will need different types of anti-asthma medicines. Your doctor will prescribe the appropriate treatment for you. There are two main types of anti-asthma medication; namely preventer and reliever medicine.

Asthma in South Africa

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Prevalence

There is undoubted evidence of a significant increase in the prevalence of asthma amongst all races in South Africa. Over the past 25 years a 25-200x rise in hospital admissions in children has been recorded in hospitals in Durban and Soweto

 

Ethnic variations

For decades, allergic diseases have been recognised to be infrequent amongst Africans. Consequently, recent studies have revealed a lower incidence of family history for atopy amongst them. However, many more Africans who have a positive family history of atopy, develop allergic diseases as compared to other races. The early exposure to foreign allergens from the newly adopted Western lifestyle have contributed to the higher degree of sensitisation recorded amongst African infants than others. These factors account for the increased prevalence noted amongst African children.

Risk of urban living

Studies conducted on rural Transkeians have shown that migration to urban and periurban settlements results in a 20x increased risk of developing asthma symptoms.

Triggers

• AIlergens. Housedust mite must be identified as the most common coastal and inland trigger factor amongst all races; even blacks in whom it was previously believed to be uncommon. In Cape Town, Durban and Transkei, grass cockroach and cat hypersensitivity have been identified as important trigger factors for inducing asthma respectively.
• Environmental factors: Air pollutants from highly industrialised areas such as the Eastern Transvaal and Gauteng, cigarette smoking, motor vehicles exhaust fumes, changing feeding practises (refined foods) and changing fuel for combustion (anthracites and coal) have been implicated in the increased prevalence of asthma.
• Occupational hazards: Prolonged exposure to many substances is regarded to be harmful to the lungs, by law and are compensatable. These include: Organic dusts (wood, grain, grain flour, tobacco), Isocyanates, formaldehyde, vapour, fumes (amines), metals (platinum, nickel, cobalt, vanadium), soldering and welding fumes, epoxy resin and acrylic acid and acrylates.

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Copyright: Allergy Society of South Africa.
Written by Dr Prakash Jeena, Dr Adrian Morris and Dr David Luyt
Endorsed by ALLSA.

ALLSA P.O. Box 88 Observatory, 7935 Cape Town, R.S.A.

Buffalo Background: Anteater