Rerni Pearce, of Ilam School, asks :-

What causes asthma?

Julian Crane, a medical researcher at the Wellington School of Medicine, responded.

The causes of asthma and allergic disease (by which I mean eczema and the ones where you sneeze) Are really not known, but wait if you please I will try and explain why some people wheeze.

The bronchial tubes are many and thin They go from the lung to under the chin They carry the air from without to within In the bronchial tubes the troubles begin.

Along with the air comes all sorts of stuff Such as pollens and dust and that animal fluff They settle inside and when there's enough The tubes start to close with a shortness of puff

We all breathe the same things day after day but only some people react in this way The reason for that may not or may be written in code in your DNA*.

(* See Jurassic Park for an explanation of DNA)

Certain substances, usually from animals or plants, get into the air and react in the bronchial tubes and give rise to narrowing of the tiny bronchial tubes in those people who are sensitive to them. The narrowing takes two forms. One is a constriction of the muscles around the airway (this is relieved quickly with medicines when someone gets an attack, usually a blue inhaler). The second form is a swelling in the bronchial tube itself and is a reaction to the animal or plant matter that has come in with the air. This can be prevented by another medicine (usually in a brown puffer, an asthma preventer) that stops the reaction taking place if it is used every day.

We do know that if there is a history of asthma in your family you have a greater chance of developing this complaint.

Why some people but not others react in this way is not known Remi. Medical scientists and molecular biologists are working hard to find the cause(s).