Vanto T, Helpphla S, Juntunen-Backman K, et al. J Pediatr. 2004;144:218–222
Purpose of the Study.
To investigate whether the development of tolerance to cow’s milk (CM) by the age of 4 years can be predicted with a skin-prick test (SPT) and measurements of total or specific IgE in the serum taken at the time of diagnosis of CM hypersensitivity (CMH).
Study Population and Methods.
Infants with immediate (n = 95) or delayed (n = 67) challenge reactions to CM were prospectively followed to 4 years of age. CMH status was assessed annually by CM challenges, initially with double-blind placebo-controlled food challenges and subsequently with open food challenges.
By the ages of 2, 3, and 4 years, children with delayed reactions developed tolerance to CM faster than those with immediate reactions (64%, 92%, and 96% vs 31%, 53%, and 63%, respectively). A wheal size of <5 mm in SPTs correctly identified 83% of 124 infants who developed tolerance to CM by the age of 4 years, and a wheal size of ≥5 mm in SPTs correctly identified 71% of 39 infants with persistent CMH. Milk-specific IgE of <2 kU/L correctly identified 82% of infants who developed tolerance to CM, and milk-specific IgE of ≥2 kU/L correctly identified 71% of infants with persistent CMH.
SPTs and milk-specific IgE in the serum are useful prognostic indicators of the development of tolerance to CM in infants with CMH.
Previous investigations have reported certain SPT wheal sizes and milk-specific IgE levels that predict a high likelihood of tolerance developing in infants and children with IgE-mediated CM allergy. The Vanto et al article addresses this very important clinical issue. In general, the study design is well done, but it would have been preferable for the investigators to have been consistent throughout the investigation and performed double-blind placebo-controlled food challenges instead of using open food challenges at the assigned follow-up evaluations. In addition, there was a mixture of patients in this investigation with 1 group encompassing classic IgE-mediated CMH and the other group representing children with non–IgE-mediated and delayed hypersensitivity reactions to CM. Despite this, the investigation does demonstrate that SPT wheal size of <5 mm and milk-specific IgE of <2 kU/L are useful prognostic indicators for the development of tolerance in children with CMH. It does not come as any real surprise that the infants with the IgE-mediated form of CMH were more likely to have a more persistent involvement than those with the non–IgE-mediated (often delayed and isolated to gastrointestinal symptoms) form of CMH and who almost always become tolerant by the age of 4 years. These data should provide useful and practical information to the clinician who manages infants and children with CMH.