Prevalence of allergen sensitization among patients with allergic diseases in Guangzhou, Southern China: a four-year observational study.

Background: The distribution of allergens may vary with different geographic areas, suggesting the importance of local epidemiological data to support evidence-based prevention and management of allergic diseases. We investigated the distribution of common allergens in allergic patients in Guangzhou, southern China.

Methods: 7,047 patients with allergic symptoms were examined for serum sIgE to 15 common allergens in this region, based on the protocol of reversed enzyme allergosorbent test.

Results: 4,869 (69.09%) of the subjects tested positive for sIgE to at least one of the 15 common allergens. There was no statistical difference in the overall rate of positive sIgE detection between males (3128/4523, 69.16%) and females (1741/2524, 68.98%). Der pteronyssinus and Der farinae were the most common aeroallergens, while eggs and cow's milk the most common food allergens, responsible for higher positive rates of sIgE responses. A good correlation in positive sIgE response was found between Der pteronyssinus and Der farinae. By age-group analysis, we noted several peaks of sensitization to certain allergens: Der pteronyssinus, Der farinae, and Blomiatropicalis at age between 9 and 12; Blattellagermanica and mosquito at age between 15 and 18, cow's milk before age 3; eggs and flour at age between 3 and 6; crabs and shrimps at age between 12 and 15. Along with older age, there was an ascending tendency in the overall positive rate of sIgE response to house dust mites among subjects who tested positive for sIgE to eggs or cow's milk.

Conclusions: Der pteronyssinus, Der farinae, cow's milk, and eggs are major allergens in Guangzhou. Sensitization to eggs and cow's milk is more common at younger age, and then gives place to the increasing prevalence of sensitization to Der pteronyssinus and Der farinae at older age. Such a sequence of events may be a result of allergy march. Knowledge on the prevalence of allergen sensitization in different age groups would help early diagnosis and intervention of allergic diseases in this large geographical region.