Influence of age on skin sensitization in atopic children

Abstract

Skin tests (ST) are one of the main tools for the diagnosis of allergy. In children, the ideal age for carrying out these tests is not specified.

The objective of this study was to identify the positivity rate of STs according to age in children and to determine the optimal age for performing ST.

Methods: This is a retrospective study carried out over a period of 27 years (1992–2019) involving children aged 1 to 15 who consulted for allergic symptoms. All the children had ST with pneumallergens.

Results: A total of 4200 children were collected. The average age was 7.6 years [1-15] years. Rhinitis was the most common respiratory manifestation found in 71% of patients, followed by asthma in 60.3% of cases. A family history of atopy was observed in 57% of children. ST was positive in 2292 children (54.57%). The positivity rate of ST increased with age, ranging from 25% at 1 year old to 72% at 14 years old. Analysis of the ROC curve showed that the optimal age for performing a first ST with better sensitivity and specificity for it to be positive is 6 years with an area under the curve equal to 0.601 and a p <0.0001. Two hundred and twelve children initially having a negative ST underwent a second ST. ST were redone within an average of 3.3 years with a positivity of 52.8%. After analysis of the ROC curve, the best sensitivity and specificity for having a second positive ST were found for the age of 8 years.

Conclusion: The optimal age for having a better ST positivity was 6 years. These results suggest that skin testing should not be generalized to all young children. However, a negative ST does not exclude the allergic nature and must be repeated from the age of 8 years if the clinical context is suggestive of allergy