Tolerability of partially and extensively hydrolysed milk formulas in children with cow's milk allergy.

Background and Objectives: The safety and tolerability of hydrolysed cow's milk protein-based formulas, particularly partially hydrolysed formulas (pHFs), in children with cow's milk allergy (CMA) remain poorly understood. We evaluated the tolerability of hydrolysed cow's milk-based formulas in children with CMA. Methods and Study Design: A three-period double-blind crossover evaluation compared the allergic tolerance against three dietary cow's milk-based formulas: extensively hydrolysed cow's milk formula (eHF), pHF, and regular cow's milk formula (rCMF). The primary outcome was the rate of tolerance against a maximum of 20.0 mL of formula. Results: Controlled food challenges were performed in 25 children (18 boys; 7 girls) with a median age of 4.25 years (range: 1-9 years) diagnosed with CMA. The median cow's milk-specific immunoglobulin E level was 31.9 UA/mL (range: 1.16-735 UA/mL). The tolerance rate ratios for rCMF were lower than those for pHF (2 vs 16; p<0.01) and eHF (2 vs 22; p<0.01). The allergic symptom scores induced by intake of pHF and eHF were significantly lower than those of rCMF (p=0.01 and p<0.01, respectively), and the pHF and eHF scores were not significantly different. Conclusions: Compared to rCMF, the partially and extensively hydrolysed whey and casein formulas evaluated in this study were better tolerated and therefore safer for children with CMA. Although further confirmation from additional centres is needed, our findings suggest the use of pHF in patients with mild CMA. Some children with CMA react to hydrolysed formulas; therefore, food challenge tests in these children should be undertaken with caution.