The cause of the inflammation which underlies most asthma in younger sufferers is one or more allergies. More people in western countries suffer from allergies, compared to people in less affluent rural parts of the world, and allergy rates are on the increase.
There is a growing body of evidence which virtually proves that asthma is an environmentally induced disease. This raises the challenging possibility that we may be able to prevent asthma by altering our environment.
Treating asthma by removing the allergic cause can be very successful when the cause is easy to remove, as when the allergic cause is a dust or vapour inhaled only at work.
The same is true when the cause is a domestic pet such as a cat or dog, though reluctance to part with a loved pet commonly prevents success.
However, the commonest cause of asthma is allergy to house dust mites, and getting rid of mites sufficiently to make a big difference to asthma requires a major change in lifestyle of the sufferer and is expensive to achieve.
There may be future treatments which modify, abolish or diminish the allergy process in the body, and this is an area of considerable research.