Mold allergens sensitization in asthma patients is associated with severity of disease

Background: Mold allergens can induce hypersensitivity reactions, including IgE-mediated disease. Exposure to mold, which are considered indoor and outdoor allergens, is associated with asthma. Furthermore, proteases produced by fungi can act as adjuvants to promote TH2 responses, disrupt the airway epithelium and increase hyperresponsiveness. Environmental control to mold is limited and, despite the pharmacological treatment available for asthma control, patients with sensitivity to mold appear to have increased risk of potentially fatal asthma exacerbations. Our objective was to evaluate mold allergens sensitization in patients with allergic asthma and correlate this with severity of disease.

Method: This was a retrospective observational study. We evaluated patients with persistent allergic asthma who were at follow-up in our clinic. Data were extracted from our electronic medical record (PRONTMED), between 2005 and 2010. Sensitization was determined by skin prick test or in vitro specific IgE detection (ImmunoCAP). We studied the following allergens: dust mites, cat, dog, cockroaches, pollen and molds (Aspegillus fumigatus, Cladosporium herbarum, Alternaria alternata, Penicillium notatum and Candida albicans). The severity of asthma was classified using GINA criteria. We excluded patients who met diagnostic criteria for ABPA.

Results: We studied 352 patients: 58 classified as mild asthma, 79 as moderate asthma and 215 as severe asthma. Mold sensitization was found in 18.96%, 18.98% and 35.34%, respectively. We did not find patients with mild or moderate asthma sensitized only to molds, but there were six patients monossensitized to mold (five to Aspergillus fumigatus).

Conclusion: Our study corroborates data recently published in the literature showing association between mold sensitization and asthma severity. However, much remains to be studied about the sources and degrees of fungal exposure, the role of exposure in the clinical outcome of asthmatic patients and the most effective measures to prevent this contact.