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Asthma characteristics

Asthma has three characteristics:

  • airflow limitation,
  • airway hyper responsiveness,
  • Inflammation of the bronchi with its associated plasma exudation, oedema, and smooth muscle hypertrophy, mucus plugging and epithelial damage.

    Asthma can be divided into:
    Extrinsic     - implying a definite external cause
    Intrinsic - when no causative means can be identified.

    Extrinsic asthma
    This occurs most regularly in individuals who show a positive skin-prick reaction to universal inhalant allergens. Positive skin-prick tests to these inhalant allergens are shown in 90% of children with persistent asthma. Interestingly though only 50% of adults veer towards this trend.

    Intrinsic asthma
    This usually starts in middle age, though many sufferers with adult-onset asthma show positive skin tests and on closer questioning often give a history of respiratory symptoms, which are compatible with childhood asthma.



    Asthma Attacks
    Asthma attacks occur when the bronchi and bronchioles become inflamed, this reduces the space throughout which air travels through the lungs. This causes the asthmatic victim to work harder to move air in and out of their lungs.

    Asthma attacks usually begin with a dry cough and mild chest heaviness. As an attack grows, wheezing develops and increases in pitch; breathing becomes more difficult and coughing produces thick, stringy mucus.

    As the airway irritation prevents some of the oxygen-rich air from reaching the alveoli in the lungs, the cells of the body start burning oxygen at a higher rate, which increases the body’s demand for oxygen.

    The frequency of asthma attacks varies considerably among asthma suffers. Some people have daily attacks, while others can go months or even years without having an attack.

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