[Classification of bronchial asthma according to steroid and immunosuppressive treatment]

In long-term management of bronchial asthma, severity is classified according to the need for steroid treatment. In mild asthma, no chronic steroid treatment is needed; bronchodilators alone can relieve symptoms. In patients with moderate asthma, continuous inhaled steroids are necessary. In severe asthma, both oral and inhaled steroids are necessary. Patients resistant to steroids are included among those with severe asthma. Patients who need 10 mg or more of prednisolone per day to control their asthma are classified as steroid resistant. However, steroid resistance has also been defined in terms of the reversibility of the forced expiratory volume 1 second (FEV1) after 1 to 2 weeks of oral steroids. The mechanism of steroid resistance remains to be clarified; functional derangement and a reduction in the number of steroid receptors on lymphocytes have been postulated as mechanisms. Turner-Warwick classified asthmatics according to the way that peak flow is affected by therapy. In her classification, patients with "brittle" asthma are likely to be steroid resistant and those with "irreversible" asthma are likely to be steroid resistant and those with "irreversible" asthma are likely to be steroid dependent. This classification implies that response to steroid therapy may be predicted from measurements of peak expiratory flow. Therefore, although the response to steroid therapy may not be useful in classifying the pathogenesis of asthma, it is one of the most important ways to classify the severity of asthma.