Page 35 - Comprehensive treatment of patients with glucocorticoid-dependent severe asthma

Exposure to occupational agents
There are more than 200 high and low molecular agents identified which can induce work-related asthma or aggravate preexisting mild to moderate asthma [18;19]. The diagnosis of occupational asthma requires objective measures [20]. Removal from exposure and reducing exposure has been shown to improve asthma symptoms and lung function, although the evidence is variable [20;21]. Therefore, the clinical benefit of removal from exposure should be balanced against the increased risk of unemployment. Since the incidence of work-related asthma is highest in the first 2-3- years of exposure [22] and young adults have the best career opportunities; early detection and removal from exposure should be considered in particular in this category of patients with work aggravated asthma [23].
Exposure to indoor-allergens
Another important issue contributing to aggravated asthma is the continuous exposure to indoor-allergens, of which house dust mites, cockroach and fungal spores are the most important contributors. Exposure to house dust mites undoubtedly contributes to the severity of asthma symptoms in sensitized patients [24;25]. Also exposure to cockroach [26], Aspergillus [27], Trichophyton [28] and Alternaria [29] has been associated with increased asthma morbidity in patients sensitized to these agents.
Despite the harms associated with exposure to indoor-allergens, the effectiveness of allergen avoidance measures is not unequivocal and continues to generate controversy [30-32]. Complete avoidance of house- dust mite allergen exposure at high altitude (> 1600 m) has shown striking improvements in asthma control, lung function and airway inflammation in sensitized children [33;34], but measures to improve asthma control by reducing mite allergen levels at sea level have been rather disappointing [31]. Even with a major reduction in allergen levels, it may take many months before the beneficial effect on symptoms, medication use, pulmonary function, airway responsiveness and immunological parameters become fully apparent [35]. Still, current guidelines and experts in the field continue to recommend environmental control as an integral part of the overall management of sensitized patients with severe asthma [36-38].
Current treatment of severe asthma
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