Better management of cow's milk allergy using a very low dose food challenge test: a retrospective study.

Background: Low dose reactive cow's milk (CM) allergic children are at high risk of persistent CM allergy and a positive oral food challenge (OFC). The present study aimed to evaluate if the results of a very low dose (VL) OFC with these children contributes to better management of CM allergy.

Methods: We retrospectively reviewed subjects with CM allergy who underwent a VL OFC with 3 mL heated CM and had a previous allergic reaction to <25 mL heated CM in the 2 years before the OFC. Subjects who passed the OFC were defined as VL tolerant, and subjects who failed were defined as VL reactive. VL tolerant subjects increased the dose to 25 mL heated CM either during an OFC in our hospital or gradually at home.

Results: Of the 83 subjects (median age, 4.3 years; range, 1.0-12.9 years) who were included, 41 (49.4%) were VL tolerant, and 42 (51.6%) were VL reactive. Thirty-nine VL reactive subjects had skin and/or respiratory symptoms during the OFC. Most reactions could be treated with an antihistamine and/or a nebulized β2 agonist. The VL tolerant subjects consumed 3 mL heated CM or 10 g butter. Within the year following the OFC, 18 VL tolerant subjects (45.0%), but none of the VL reactive subjects, were able to consume 25 mL heated CM (p < 0.001).

Conclusions: A VL OFC allows the management of some low dose reactive CM allergic children to change from complete avoidance to partial intake of CM.