Background: In Japan, morbidity of Japanese cedar pollinosis has dramatically increased, especially in children. However, little is known about the prevalence of pollinosis and sensitization to Japanese cedar pollen (JCP) in young children.
Objective: The aim of this study is to investigate the prevalence of sensitization to JCP in allergic and non-allergic children from infancy to adolescence.
Methods: Two hundred forty three children with allergic diseases (age 8 months-16 years, mean 5 years) and 137 children without allergic diseases (age 1 month-15 years, mean 4 years) were recruited. Their specific IgE to JCP, house dust mite, orchard grass pollen, egg white, and milk were measured with the CAP-RAST system. A questionnaire was filled out by their parents.
Results: The percentage of positive (> or = 2) CAP-RAST to JCP was 47.1% in children with allergic diseases and 19.9% in children without allergic diseases. In children with allergic diseases, the ratio had risen rapidly from 3 to 5 years old. In children without allergic diseases, the ratio of JCP sensitization has gradually increased from the infancy to adolescence. The youngest child who had been sensitized to JCP was 23-month-old boy with atopic dermatitis. The proportion of children who were born from January to march was significantly higher in JCP sensitized group than JCP non-sensitized group. The ratio of house dust mite and orchard grass pollen sensitization was higher in JCP sensitized group than those in JCP non-sensitized group.
Conclusion: Large number of children acquire sensitization to JCP in their preschool age. We need to develop the way how to protect JCP sensitization in the early stage of life.