A Comparative Study of Skin Prick Test versus Serum-Specific IgE Measurement in Indian Patients with Bronchial Asthma and Allergic Rhinitis.

Background. Skin prick testing (SPT) is the ‘gold standard’ in the assessment of allergic sensitivity to inhalant allergens. Serum-specific immunoglobulin E (SSIgE) measurement is a complementary test. SPT is performed with antigen extracts from India while SSIgE utilises extracts derived from European antigens. Objective. To evaluate the performance of allergic assessment by SSIgE against cockroach, housefly and mosquito aeroallergens which are frequently implicated in driving respiratory allergies in India considering SPT as the ‘gold standard’. Methods. Twenty patients (mean age 28.5 years; range 15-50 years) diagnosed to have bronchial asthma and/or rhinitis underwent SPT. The SSIgE levels were obtained at the same visit. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of SSIgE testing were calculated using SPT as the ‘gold standard’. The correlation between SPT grading and SSIgE levels was also evaluated. Results. The sensitivity of SSIgE testing to each of the 3 aero-allergens was >85%. The PPV of cockroach and mosquito SSIgE was >85%; housefly SSIgE had PPV of 68.7%. The two tests were in agreement in 85% (cockroach), 90% (mosquito) and 55% (housefly). There was a significant correlation between the grades of SPT reactions and SSIgE levels. Conclusions. The SSIgE has higher sensitivity and PPV, but lacks specificity. Higher sensitivity with low specificity leads to increased false positive diagnosis of allergic disease. Unlike allergenic pollens, however, insect antigen extracts from different regions seem to give comparable results, and can thus, reliably be used in the evaluation of allergy.

Indoor air pollution and respiratory illness in children from rural India a pilot study.

Objective. Indoor air pollution measured in terms of particulate matter <2.5μm in diameter (PM2.5), is an important cause of respiratory illness in children. Therefore, PM2.5 levels in rural households and its correlation with respiratory illness-related symptoms in children were studied. Methods. A questionnaire-based survey of children for respiratory illness-related symptoms was conducted in 37 households of a village (Khanpurjupti, Delhi-NCR, India) from September 2011 to October 2011. Assessment of 24-hour PM2.5 level was done using University of California-Berkeley Particle and Temperature Sensor (UCB-PATS). Results. Thirty-seven households in a rural area were studied. These were divided into 20 respiratory households, i.e. those with children with respiratory illness-related symptoms and 17 control households. The 24-hour PM2.5 was measured in all the houses. The average minimum and maximum PM2.5 levels were 7.24mg/m3 and 22.70mg/m3, respectively (mean=10.47mg/m3) among the 20 respiratory households. The average minimum and maximum PM2.5 levels were 1.10mg/m3 and 18.17mg/m3, respectively (mean=4.99mg/m3) in the 17 control households. The PM2.5 levels were significantly greater (p<0.05) in houses where children had respiratory symptoms compared to the control households. Further, biomass fuel use and number of family members were significantly associated with respiratory illness in children. Conclusion. Increased PM2.5 levels, biomass fuel use and number of family members were found to be associated with increased occurrence of respiratory illness in children.

Correlation of atopy and FeNO in allergic rhinitis an Indian study.

Background. Fractional exhaled nitric oxide (FeNO) is a non-invasive marker of airway inflammation. Limited published data are available on the effect of atopy on FeNO in allergic rhinitis. Objectives. To investigate the relationship between atopy and FeNO in patients with allergic rhinitis. Methods. Patients with allergic rhinitis were assessed for atopy and exhaled breath analysis of nitric oxide. Atopy was assessed by skin prick testing (SPT) against 58 common aero-allergens; a wheal size of 3mm or more as compared to buffer saline was considered positive. Patients were labelled to be atopic if they had at least one positive SPT result. The measurement of FeNO level was done by using NIOX chemiluminescence analyser. Results. Forty-nine participants (26 males) aged between 8-50 years were studied and 31 of them were found to be atopic. The average value of FeNO in the subjects studied (n=49) was 26.0±22.7 parts per billion (ppb) with significantly higher values being observed in atopic group as compared to non-atopic group (34.2±24.3 versus 11.9±9.0 ppb; p<0 .05). Conclusion. As FeNO is a marker of lower airway inflammation, significantly higher FeNO levels in atopic allergic rhinitis patients suggest that it may be a predictor for onset of asthma in these patients.