Asthma is one of the is one of the most common respiratory diseases in the world today, affecting one in ten children (10%) and one in twenty adults (5%). Asthma occurs for the first time at any age, even in adulthood, although it usually begins before the age of five years.
A few children affected will “outgrow” asthma during their teenage years although it usually persists if contracted in adulthood
- tends to run in families, as do related allergic conditions, such as hay fever and eczema.
- 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 sometimes it is not recognised and treated, in which case the patient undergoes unnecessary suffering.
What happens to the lungs in asthma?
Asthma affects the breathing pipes or tubes called airways or bronchi. When one takes a breath, 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 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.
Asthma is characterised by narrowing of the bronchi caused by:
- swelling of the lining
- increased sticky mucus or secretions lying in the airways produced by the mucus glands. The swelling and increased secretions are called inflammation.
- muscles going into spasm. Spasm occurs only when there is inflammation.
When the bronchi become too narrow, or are partially obstructed due to inflammation and spasm, the typical symptoms of asthma will develop.
These symptoms are:
- coughing which often occurs more frequently with activity and at night. This can be dry or wet and is persistent or recurrent
- wheezing which is a whistling noise in the chest
- tightness of the chest causing difficulty in breathing
- 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. It is also a condition that runs in families.
What starts an asthma attack?
- A viral cold or flu can aggravate asthma symptoms temporarily. This effect may last for up to six weeks after the illness.
- Asthma attacks are sometimes triggered by an allergy to airborne particles including house-dust mites, grass or tree pollens, fungal spores and skin flakes from furry animals such as cats and dogs. On rare occasions certain foods and additives may also trigger off asthma when taken by mouth.
- Pollution in the environment, especially cigarette smoke, car exhaust fumes and certain chemical gases can aggravate an asthma attack. Children will even be affected by passively inhaling their parents’ cigarette smoke.
- Sport and exercise, particularly in cold weather, can set off an asthma attack. However with the correct treatment asthma can be well controlled so that asthmatics need not avoid sport or exercise. In fact about 10% of Olympic athletes have asthma.
- Emotion such as excitement, anger, fear or laughter can aggravate asthma. So-called “nerves” are not responsible for causing asthma.
- Drugs. Certain commonly used medicines such as aspirin and other anti-pain and anti-inflammatory tablets may trigger an asthma attack. . Be cautious when using “beta blocker” blood pressure tablets or eye-drops for glaucoma as they may also trigger off asthma in adult life.
How is asthma treated?
Asthma cannot be completely cured, no matter what anyone says, but with the correct treatment most asthmatics will be able to 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 as possible to ordinary life. (See 'Asthma medicines and how they work')
Asthma in South Africa
There is undoubtedly evidence of a significant increase in the number of people who have asthma amongst all races in South Africa. Over the past 25 years a 25 to 200 times rise in hospital admissions for asthma have been recorded in hospitals in Durban and Soweto.
For decades it was accepted that allergic diseases were infrequent amongst Africans, Subsequently recent studies have confirmed a lower incidence of family history for allergy amongst them. However, many more Africans than other races with a positive family history of allergy, develop allergic diseases. The early exposure to foreign allergens from the newly adopted Western lifestyle has contributed to a higher degree or sensitisation recorded amongst African infants than in other races. These factors account for the increased number of African children who have asthma.
Exposure to urban living
Studies conducted on rural Transkeians have shown that migration to urban and peri-urban settlements has resulted in a 20-times increased risk of developing asthma symptoms although the incidence of asthma in rural areas has also increased.
Allergens. House dust mite is the most common coastal and inland trigger factor amongst all races; even amongst blacks in whom it was previously believed to be uncommon. In Cape Town, Durban and Transkei, grass, cockroaches and cat allergies have been identified as important trigger factors causing asthma.
Air pollutants from highly industrialised areas such as Durban, Mpumalanga and Gauteng, cigarette smoking, motor vehicles exhaust fumes, changing eating habits by consuming refined foods and using anthracite and coal as fuel have been implicated in the increased prevalence of asthma.
Prolonged exposure to many substances which are regarded as being harmful to the lungs. By law such an occupation-induced asthma is 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.
(Robin J. Green)
The information provided in this article was correct at the time of publishing. At Mediclinic we endeavour to provide our patients and readers with accurate and reliable information, which is why we continually review and update our content. However, due to the dynamic nature of clinical information and medicine, some information may from time to time become outdated prior to revision.