IgE-Mediated Sensitization to Mould Allergens among Patients with Allergic Respiratory Diseases in a Desert Environment

Abstract

Background: The importance of fungal allergens in the development of allergic diseases in a desert environment is uncertain. This study evaluated the prevalence of IgE sensitization to moulds among patients with allergic respiratory diseases in Kuwait – a desert country. Methods: A total of 810 patients (male:female ratio 1.4) with a mean age of 32.3 years (range 2–76 years) with extrinsic asthma or allergic rhinitis were studied. Sera from the patients were tested by the CAP-RAST method for specific IgE to 6 fungi (Penicillium, Cladosporium, Aspergillus, Candida, Alternaria and Helminthosporium). For comparison house dust mite and Bermuda grass were also assessed. Results: The overall positivity to at least one mould was 20.9%. Among 120 matched control subjects, the value was 5.8%. The value was much higher among patients with asthma alone (45.8%) or both asthma and rhinitis (28.3%) than those with rhinitis alone (11.8%; p < 0.001). Asthmatic children had the highest sensitization rate (66.0% in the 7- to 12-year age group), which declined sharply with age. Among asthmatics, Candida and Aspergillus had the highest sensitization rates (23.1 and 21.3%, respectively), followed by Helminthosporium (18.8%), Cladosporium (15.9%), Alternaria (14.6%) and Penicillium (13.9%). The values for mite and Bermuda grass were 41.2 and 54.6%, respectively. Among asthmatic children, severe asthma was significantly more frequent among mould-positive (51.6%) than mould-negative patients (17.5%; p < 0.0001). Conclusions: Even in this desert environment, sensitization to moulds is quite common among patients with allergic respiratory diseases, with a striking preponderance among children with asthma. Mould allergy could also be an important factor determining asthma severity in this environment.