Corticosteroid-resistant asthma: fundamental aspects

A controversial definition: The current definition of corticosteroid-resist ant asthma is a spirometry definition. There is however, no consensus an do se, treatment duration, steroid administration route and the degree of FEV1 non-reversibility allowing the diagnosis of corticosteroid-resistant asthm a. Finally, the beneficial effect of steroids in clinical terms (symptom fr equency, nomber of hospitalizations, quality of life) is not taken into con sideration. thus nearly one-half al ail patients included in studies on cor ticosteroid resistance are taking long-term oral steroids. This subgroup of patients must be considered individually when examining these studies. Complex pathogenesis: There are a wide range of anomalies described in the literature involving: glucocorticoid pharmacokinetics, cytokine regulation, cell function (monocytes, lymphocytes, eosionophils), and transcription fa ctors (glucocorticoid and AP-I receptors). Difficult therapeutic management: There are several prerequisites before pr oposing exceptional regimens using cyclosporine, gold salts, methotrexate, or immunoglobulins: i) certain diagnosis of asthma (with CT can and ultraso nographic explorations ii needed, ii) proper control of environmental facto rs and good compliance, iii) proof of the absence of clinical benefit with long-term corticosteroids. These exceptional therapeutic schemes have their disadvantages and are only warranted by clinically patent corticosteroid r esistance (whatever the "biological" cause).