Sensitization profile in differential diagnosis: allergic asthma vs. chronic (nonspecific) cough syndrome

In the subgroup of children with chronic cough, distinguishing children with allergic asthma from those with non-specific respiratory symptoms is difficult. We have focused on determination of diagnostic efficiency of serum total IgE, sIgE, and skin prick test in differentiation of asthmatic children from children with nonspecific respiratory symptoms. A total of 131 children with median age of 7.5 years were enrolled in study and divided into 2 groups; children with allergic asthma (N=71) and children with chronic cough (N=60). Participants underwent the standard allergological examination, including skin prick test and measurement of total IgE, and following 3 allergen-specific IgE antibodies against aeroallergens: Dermatophagoides pteronyssinus, Ambrosia artemisiifolia, and Phleum pratense. The percentage of patients with elevated level of total and sIgE was higher in children with allergic asthma than in children with chronic cough syndrome (P=0.0001). In children with asthma, sIgE had a better diagnostic value than total IgE. The best diagnostic efficiency of cut-off values for sIgE was shown for Der p sIgE. Skin prick test to all allergens had 78.82% sensitivity and 91.3% specificity in differentiating the 2 tested groups. The highest sensitivity and specificity in skin prick test was proved for Dermatophagoides pteronyssinus. The sensitization profile consisting of total IgE, sIgE levels, and SPT clearly distinguishes children with allergic asthma from children with chronic nonspecific cough, but still with overlap. Therefore, diagnosis should always be confirmed by a thorough allergy investigation.