Evaluation of skin prick test to screen dust mite sensitization in chronic respiratory diseases in Southern Vietnam

Abstract

Background: In the view of the epidemic growth of sensitization to indoor allergens in Southern Vietnam, there is a requirement to screen large population.

Objective: To evaluate skin prick tests (SPTs) as predictors of positive specific IgE (sIgE) to dust allergens, among patients with chronic respiratory diseases (CRDs).

Methods: The sensitization to Blomia tropicalis (Blo t), Dermatophagoides pteronissinus (Der p), and Blattella germanica allergens (Bla g) were evaluated among 610 CRD, both SPT (≥4 mm) and sIgE by immuno-CAP (≥0.7 kU_A/L).

Results: Based on sIgE, 45%, 32%, and 33% of patients with CRD were sensitized to Blo t, Der p, and Bla g, respectively, compared to 19%, 18%, and 13% by SPT. The association between SPT and sIgE was statistically significant, though the Kappa factor was fair (i.e., 0.39 to 0.23). While the specificity of SPT to detect sensitization (compared to sIgE) was >90% among the whole population, the sensitivity was only 34%, 41%, and 24% for Bo t, Der p, and Bla g, suggesting that SPT was not enough sensitive to screen the indoor allergen sensitization. Though, among the <10 pack-year (PY) smokers, the sensitivity was 43% for Blo t, 52% for Der p, and 61% for Blo t and/or Der p, compared to 27%, 30%, and 35% among the ≥10 PY smokers. The sensitivity/specificity was not associated with the diagnosis of asthma compared to chronic obstructive pulmonary disease.

Conclusion: In the present circumstance, SPT to dust mites allergens can be used to detect a sensitization among CRD population in Southern Vietnam.

Keywords: Allergen; Chronic respiratory diseases; Immunoglobulin E; Skin test; Vietnam.

Fig. 1. Prevalence of allergen sensitization. (A) Prevalence of positive skin prick test (SPT). (B) Prevalence of positive sIgE. The black bars indicate a cutoff of 0.35 kU_A/L and the white bares show a cutoff of 0.70 kU_A/L specific IgE (sIgE). Blo t, Blomia tropicalis; Der p, Dermatophagoides pteronyssinus; Bla g, Blattella germanica; Bla a, Blattella americana; Bla o, Blattella orientalis.