A comparative study of immediate skin test reactivity to inhalant allergens in asthmatic children of two different regions in Saudi Arabia.

The skin test reactivities to various inhalant allergens in asthmatic children from two different regions in Saudi Arabia were compared. One hundred-twenty subjects each from the Central and Western regions, representing different environmental features, were selected. Prick test reactivity to 24 common allergens were analyzed and compared. Seventy-one (59.2%) patients from Riyadh (Central region) showed positive skin reactions to one or more allergens, while 87 (72.5%) reacted positively to different allergens from Makkah (Western region). The distribution of skin test sensitivity revealed striking differences in the two groups. The most prominent were reactions to the house dust mite (D. farinae) which amounted to 56.3% and to fungal allergens, 31.3% in asthmatics from the Western region, while reactions to the same allergens in subjects from the Central region were 10% and 5.8%, respectively. Similarly, marked variations were noted with pollen grain allergens with 9.3% in Central region and 15.4% in the Western region. The study indicates the presence of different allergen profiles in the two regions and suggests the influence of climatic and environmental factors and their impact on sensitization of susceptible subjects.