Severe asthma and fungi: current evidence

Bronchial asthma is an inflammatory disease of the airways which may be worsened due to numerous extrinsic factors. The most common trigger is continuous exposure to allergens of which fungal agents are important factors. There is overwhelming evidence for the presence of fungal sensitization in patients with asthma. The diagnosis of fungal sensitization can be made either with skin testing with antigens derived from fungi or measuring specific IgE levels. There is also a strong association between fungal sensitization and severity of asthma. Whether this relationship is causal or just casual remains to be investigated. A variety of fungi are known to cause sensitization in asthmatics, but the most important fungal agent(s) causing severe asthma with fungal sensitization (SAFS) are currently unknown. Aspergillus species seem to be the strongest candidates as only with Aspergillus spp. does one encounter two extreme immunologic phenomena, i.e., the Aspergillus-sensitive asthma and allergic bronchopulmonary aspergillosis. The initial clinical management of SAFS should be the same as asthmatics without fungal sensitization. There is some evidence of the role of itraconazole in the management of SAFS but its routine use in SAFS requires further evaluation. This review summarizes the current evidence on the link between fungi and severe asthma.