Asthma is an inflammatory reaction along the bronchial tree. An allergic trigger or infection causes an increase in mucous, giving a cough, and small circular muscles along the lining start to tighten, giving wheezing. The person feels shortness of breath – as if he or she is breathing through a straw.
The most common cause of asthma for young children is respiratory viruses. As they attach to the respiratory lining, they induce a cascade of immune responses that trigger histamine release. This leads to increased mucous production and microscopic swelling of the lining. As immune cells migrate to the respiratory lining in response to the infection, there can be tightening of the underlying muscles, giving wheezing in the asthmatic child.
The reasons why some people wheeze and others don’t are very complex. It is thought that asthmatics respond to respiratory viruses with a ‘hyperactive’ profile of T cells, cytokines and other immune substances. A tendency towards asthma can be inherited. The environment also plays a big role. When a child has a virus, the respiratory lining is more susceptible to airborne allergens. While a child is fighting off a bronchial infection, the T cells that have been mobilized can be turned into “allergy” cells, so that a child can become sensitized to smoke, smog and other irritants when exposed to them during a cough/cold.
Many medicines are used for asthma. Some are used to stop an attack and others are used to prevent them. Bronchodilators have been used for decades, and more recently, new medications such as inhaled steroids and leukotriene modifiers have been used to “calm” the asthmatic’s overactive immune response.