The Significance of Serologic Allergy Tests in Children with Recurrent Pneumonia

Sim, Yoon Hee; Yun, Sin Weon; Chae, Soo Ahn; Lee, Dong Keun

Abstract

PURPOSE
Pneumonia is one of the most common respiratory diseases in hospitalized children, and often recurs. It has been reported that asthma is one of the significant contributing factors to recurrent pneumonia. On the basis of similarities between asthma and recurrent pneumonia, we intended to evaluate the influence of allergy on recurrent pneumonia.
METHODS
Seventy one children with recurrent pneumonia were defined as recurrent group(RG) and twenty one children with first episodes of pneumonia were defined as control group(CG). WBC, total eosinophil count, Eosinophilic Cationic Protein(ECP), serum total IgE and specific IgE for eleven common allergens using the CAP system were measured and compared. Recurrent pneumonia was defined as at least two pneumonia episodes in a year, or at least three episodes from birth to the time of our study. Children with previous allergic disorders were excluded.
RESULTS
There were no statistical differences in WBC, total IgE, and ECP between the two groups. Total eosinophil count in RG was significantly higher than CG(P=0.021), significantly correlating with ECP(r=0.755, P<0.05) and total IgE(r=0.354, P<0.05). When the cut-off value was 0.35 kU/L in CAP test, positive prevalence of CAP in RG was significantly higher than CG(P=0.009). Also, the positive prevalence of house dust mites group, especially Dermatophagoides farinae(D.f.), was significantly higher in RG(P=0.019, 0.025, respectively). When the cut-off value was 0.7 kU/L in CAP test, only a positive prevalence of house dust mites group was significantly higher in RG than CG (P=0.042). The quantitative levels of specific IgE for Dermatophagoides pteronyssinus(D.p.) and D.f. were very high in RG(P=0.018, 0.028, respectively), significantly correlating with each other(r=0.639, P<0.05).
CONCLUSION
Allergic sensitization, especially to house dust mites, is one important contributable factor in recurrent pneumonia in children. Further study, such as bronchial hyperresponsiveness, is needed in children who were sensitized by D.p. or D.f..