Usefulness of analytic tests for the diagnosis of cow's milk protein allergy

Cow's milk protein allergy is the most common food allergy among children. It can be diagnosed based on a guided history taking and using an oral food challenge (OFC), serum specific immunoglobulin E levels (sIgE), and skin prick tests (SPT). However, it is difficult to establish their diagnostic performance in the local population. Our objective was to assess the usefulness of tests used to diagnose cow's milk protein (CMP) allergy in the studied population.

Retrospective analysis of data from patients seen at the Unit of Allergy of a tertiary care pediatric hospital between 2015 and 2018. SPT and sIgE tests were done for milk, alpha-lactalbumin, beta-lactoglobulin, and casein, followed by an OFC, and the diagnostic usefulness of each test, as well as their combination, was established.

The tests of 239 patients were assessed. OFC was performed at the hospital in 54.8% of cases, via a rechallenge test at home in 35.5%, and through CMP intake by the mother in 9.6%. The highest specificity was observed with the casein SPT (96.7%; 95% confidence interval [CI]: 90.8-99.3) and the highest sensitivity, with the 4-allergen SPT and sIgE combination (55.3%; 95% CI: 45.7-64.6).

The study established the diagnostic usefulness of SPT and sIgE in the studied population.