Introduction

Asthma has been recognised since antiquity. The word comes from the Greek ασθμα, ασθματος meaning a ‘short-drawn breath, hard breathing, or death rattle’ and was a term used to describe a complex of symptoms rather than a specific disease entity. Early pathogenic models suggested that airflow to the body was impeded by phlegm from the brain lodging in the lungs; there was also recognition of an association with environmental factors, including climate and geographical areas.