The effect of follow-up after a negative double-blinded placebo-controlled cow’s milk challenge on successful reintroduction

Cow’s milk allergy is a common food allergy in children with an incidence of 1–3%. The gold standard to diagnose cow’s milk allergy is a double-blinded placebo-controlled food challenge (DBPCFC). Previous studies show that reintroduction of cow’s milk is unsuccessful in 10–12% of patients. The aim of this retrospective study is to evaluate the effect of follow-up on the reintroduction of cow’s milk. We analyzed the data of patients with a negative DBPCFC for cow’s milk between 2014 and 2016 in three different departments. Questionnaires were used to compare the three ways of follow-up (no follow-up, follow-up in person or by telephone). Of the 336 children with a negative DBPCFC for cow’s milk, 128 questionnaires (41%) were returned. Reintroduction of cow’s milk was unsuccessful in 13.3% of the patients. There was no significant difference found between children with (73.8%) or without (26.2%) follow-up, or between follow-up by phone or personally. Whether this finding is caused by small numbers within this retrospective study should be investigated in future prospective studies.