Sensitization to aeroallergens among patients with allergic rhinitis in a desert environment

Background: The causative allergens of allergic rhinitis in desert environments are uncertain. Objective: To determine the sensitizing aeroallergens in patients with allergic rhinitis in Kuwait, a desert country. Methods: A total of 706 patients aged 6 to 64 years (mean 34.3 years) with allergic rhinitis were studied. Sera from the patients were screened for specific IgE to 14 inhalant allergens by the CAP-RAST method. Results: Specific IgE to any allergen was detected in 86.3% of patients. The prevalence rates for allergen groups were: pollens (77.3%), house dust (62.3%), and molds (14.7%). The individual allergens with the highest positive rates were pollens of the weed Chenopodium (64.3%); Bermuda grass (55.0%), and Prosopis tree (50.3%). These plants were all imported and cultivated for the purpose of "greening" the desert. German cockroach (48.2%) and house dust mites (32.4% to 39.2%) were the most prevalent indoor sensitizers. With the exception of the molds, sensitization rates were higher for males than females. The youngest age group (6 to 17 years) had significantly higher sensitization rates than the older ones, particularly with respect to the molds (P < .01 to .001). Severe sensitization was more common with Alternaria than the other allergens and in general mold sensitization was more frequently associated with severe symptoms. Polysensitization was very common, with 81.8% of all sensitized patients positive to more than one allergen. Conclusions: Pollens of the local horticultural plants are the main sensitizing allergens among patients with allergic rhinitis in this desert environment. The practices that "green" the desert seem to also encourage allergen sensitization.