Causes of Asthma
It is believed that asthma arises from the interaction of both genetic and environmental factors.
Genetic factors
There is a strong association between asthma and atopy (allergy tendency), which tends to run in families. First-degree relatives of an asthmatic have a tenfold risk of developing asthma themselves.
Environmental factors
- Viral infections- colds, flu and chest infections
- Pollens and moulds- especially grass pollen and fungal spores, which are in the air at different times of the year.
- Cold air- or change in temperature and humidity
- Excessive exercise- however, moderate exercise is good for asthmatics and many asthmatics take a “reliever” before anticipated exercise.
- Emotion - severe anxiety or stress can worsen asthma and bring on an attack, but there is no evidence of increased psychological disturbance in asthmatics.
- Irritant dusts, vapours and fumes - such as perfume and cigarette smoke.
- Atmospheric pollution - nitrous oxide, sulphur dioxide, ozone, smoke, etc.
- Specific occupational sensitizers - fumes from paints, solvents, flour and solders.
- House dust mite - this is the most important extrinsic cause of asthma, world-wide.
Asthma attacks are likely to occur early in the morning, when the effects of protective medications may have worn off, and when the body is least able to resist the effects of triggers.
