The diagnosis of asthma

There are three steps in establishing the diagnosis of asthma in a child presenting with recurrent wheezing or recurrent coughing. The first is to decide whether the symptoms are due to asthma, the second is to consider possible aetiological factors--mainly to reassure the parents that there is nothing particular in this area that need be done--and the third is to determine what is the pattern of airways obstruction. Is it purely episodic or alternatively, are there periods where it persits? In younger children, clinical evidence alone is all that is available to decide whether the respiratory symptoms are due to asthma, and to determine its pattern. In older children, pulmonary function tests are very helpful.