Single-dose oral challenges to validate eliciting doses in children with cow's milk allergy.

BACKGROUND

There is increasing interest in the use of eliciting doses (EDs) to inform allergen risk management. The ED can be estimated from the distribution of threshold doses for allergic subjects undergoing food challenges within a specified population. Estimated ED values for cow's milk (the dose expected to cause objective allergic symptoms in 5% of the milk-allergic population) range from 0.5 mg to 13.9 mg cow's milk protein. We undertook a single-dose challenge study to validate a predicted ED for cow's milk of 0.5 mg protein.

METHODS

Participants were recruited from 4 clinical centres. Predetermined criteria were used to identify patients reacting to 0.5 mg cow's milk protein (approximately 0.015 mL of fresh cow's milk). Children over 1 year underwent formal challenge to cow's milk to confirm clinical reactivity.

RESULTS

172 children (median age 6.0 (IQR 0.7-11) years, 57% male) were included in this analysis. Twelve (7.0%, 95% CI 3.7%-11.9%) children experienced objective symptoms that met the predetermined criteria. One participant had mild anaphylaxis that responded to a single dose of adrenaline, the remainder experienced only mild symptoms with no treatment required. We did not identify any baseline predictors of sensitization that were associated with objective reactivity to the single-dose challenge using 0.5 mg cow's milk protein.

CONCLUSIONS

These data support an estimated ED for cow's milk of 0.5 mg protein. Values for ED above 0.5 mg for cow's milk protein proposed for allergen risk management need to be reviewed.