Allergic Comorbidity of Asthma or Wheezing, Allergic Rhinitis, and Eczema: Result From 333 029 Allergic Children in Shanghai, China

Abstract

Background Allergic diseases have become a worldwide public health concern. A defining feature of allergic diseases is they often coexist in children from birth to adolescence. Objective To investigate the prevalence of comorbid allergic diseases in allergic children in Shanghai, China. Methods A retrospective study of 333 029 children diagnosed with allergic diseases aged 0 to 12 years (mean age: 3.04 years, 59.3% boys) was conducted using the electronic medical records of Shanghai Children’s Hospital from January 2013 to July 2018. Comorbidity of allergic diseases is defined as the coexistence of 2 or 3 following diseases in the same child such as asthma (AS)/wheezing, allergic rhinitis (AR), or eczema (EC). Results The proportion of children with comorbid allergic diseases was 6.7% (22 351/333 029). Among them, EC + AS/wheezing was the most common (61.3%, 13 711/22 351). Children with a comorbidity had significantly earlier disease onset age than subjects with only 1 disease (2.72 vs 3.06, P < .05). The serum total immunoglobulin E (tIgE) levels of children with comorbid allergic diseases were higher than those with only 1 disease. In children with a disease onset age of 0 to 9 years, the levels of tIgE for children with AS/wheezing + EC were higher than children with AS/wheezing only or EC only; in children with disease onset age of 2 to 5 and 10 to 12 years, the levels of tIgE for children with AS/wheezing + AR were higher than children with AS/wheezing only or AR only; in children with a disease onset age of 2 to 5 years, the levels of tIgE for children with AR + EC were higher than children with AR only or EC only. Conclusion Comorbidity of allergic diseases is common in children in Shanghai, China. The onset age of comorbidity is earlier than that of only 1 disease, and the levels of serum tIgE are higher in patients with an allergic comorbidity.