Three-year prognoses after low-dose oral food challenge for cow's milk.

Background: Low-dose (LD) oral food challenge (OFC) with heated cow's milk (CM; 3 mL) effectively prevents CM elimination in children with CM allergy (CMA). We investigated the long-term prognoses after an LD-OFC for CMA.

Methods: Children with immediate CMA symptoms after consuming <25 mL of CM within 2 years of a baseline LD-OFC were retrospectively analyzed. Children who successfully passed the baseline LD-OFC (LD-passing) continued consuming 3 mL of CM at home, whereas those who failed (LD-failing) continued to avoid CM. Dose escalation occurred through stepwise OFCs or gradually at home. CM tolerance was defined as the ability to repeatedly consume ≥100 mL CM without experiencing symptoms; the inability to do so indicated persistent CMA. The prognoses of the LD-passing and LD-failing groups within 3 years of LD-OFC were compared.

Results: Among 113 children, the median age at baseline LD-OFC was 2.8 years; 41 % had an anaphylaxis history, with equal distribution between the LD-passing and LD-failing groups. Three years later, 63 % and 5 % of children demonstrated CM tolerance in the LD-passing and LD-failing groups, respectively (p < 0.001). In the LD-passing group, predictors of persistent CMA were older age (adjusted hazard ratio [95 % confidence interval], 1.37 [1.00-1.88]), higher CM-specific IgE level (2.95 [1.30-6.68]) and other food allergies (2.34 [1.12-4.90]).

Conclusions: Failure in LD-OFC is associated with persistent CMA, whereas successful LD-OFC outcomes are associated with a favorable prognosis thereafter, irrespective of a history of anaphylaxis.