Natural history of cow's milk allergy in children aged 6-12 years

Approximately 50%-90% of children with immediate-type cow's milk allergy (CMA) acquire tolerance by pre-school age. We aimed to investigate the acquisition rate of CMA tolerance in children aged 6-12 years.

We included children with CMA who persisted until the age of 6. Tolerance was defined as passing an oral food challenge with 200 mL of unheated cow's milk (CM) or consuming 200 mL of CM without symptoms, whereas persistent CMA was defined as fulfilling neither of these criteria by 12 years old. Children receiving oral immunotherapy (OIT) were excluded from the primary analysis. Risk factors associated with persistent CMA were assessed using Cox regression analysis.

Of 80 included children, 30 (38%) had previous CM anaphylaxis, and 40 (50%) had eliminated CM completely from their diet. The median CM-specific immunoglobulin E (sIgE) level at 6 years old was 12.0 kU_A /L. Tolerance was acquired by 25 (31%) and 46 (58%) children by the age of 9 and 12 years, respectively. At baseline, persistent CMA was associated with higher CM-sIgE levels (hazard ratio 2.29, 95% confidence interval 1.41-3.73, optimal cutoff level 12.7 kU_A /L), previous CM anaphylaxis (2.07, 1.06-4.02), and complete CM elimination (3.12, 1.46-6.67). No children with CMA who had all three risk factors (n = 14) acquired tolerance.

Except for OIT patients, more than half of children with CMA at 6 years old acquired tolerance by 12 years old. Children with CMA who have the risk factors are less likely to acquire tolerance.