Asthma in the desert: spectrum of the sensitizing aeroallergens

Background: Bronchial asthma is common in Kuwait, a desert country, but the sensitizing allergens are uncertain. This study investigated the sensitizing allergens in Kuwaiti patients with extrinsic asthma. Methods: A total of 553 asthmatics (male:female ratio: 1.4; mean age: 31.7 years [range 3-76 years]) and 112 matched controls were studied. Sera from all patients/subjects were tested by the CAP-RAST method for specific IgE to 14 locally relevant inhalant allergens. Results: Specific IgE to at least one allergen was detected in 87.2% of the patients compared with 24.1% of controls. Among the confirmed extrinsic asthmatics, the sensitization rates for the allergen groups were as follows: pollens (87.1%), house dust (76.1%), and molds (30.3%). The three most prevalent sensitizing pollens were from Chenopodium (70.7%), Bermuda grass (62.9%), and Prosopis (62.7%), all of which are horticultural plants imported for the purpose of "greening" the desert. For all allergens, except the molds, the prevalence rate was higher in males than females, but age had only a weak effect. Severe asthma occurred significantly more frequently among mold-sensitized patients. Conclusions: These results show that even in a desert environment, pollens and house-dust allergens may be important sensitizing allergens. They also illustrate how practices that "green" the desert can affect public health.