<b><i>Introduction:</i></b> Cow’s milk allergy (CMA) is a common diagnosis in infants, requiring the exclusion of cow’s milk until tolerance is recovered. In the present study, we aim to determine which factors are associated with the development of tolerance. <b><i>Methods:</i></b> Retrospective, observational study of subjects who underwent the same clinical follow-up methodology. We studied 245 cases of CMA (125 IgE-mediated and 120 non-IgE-mediated). The following variables were analysed: age at diagnosis, gender, type of delivery, type of feeding received, feeding during the first months of life, clinical features, and type of feed received as treatment: casein hydrolysates or casein hydrolysates with <i>Lactobacillus rhamnosus</i> GG (LGG). <b><i>Results:</i></b> Factors associated with earlier tolerance were non-IgE-mediated CMA (HR = 2.92; 95% CI: 2.20–3.88) and patients receiving casein hydrolysate with LGG (HR = 1.79; 95% CI: 1.33–2.42). Later tolerance was associated with caesarean delivery (HR = 0.78; 95% CI: 0.58–1.05) and breastfeeding for a period of at least 3 days (HR = 0.64; 95% CI: 0.44–0.93). The multivariate study shows that the type of formula (HR = 1.61; 95% CI: 1.19–2.18) and the type of CMA (HR = 2.82; 95% CI: 2.12–3.85) have an effect on the recovery time. Casein hydrolysates with LGG reduces the recovery time in IgE-mediated (HR = 1.88; 95% CI: 1.17–3.01) and non-IgE-mediated CMA (HR = 1.46; 95% CI: 0.98–2.17). <b><i>Conclusions:</i></b> Tolerance acquisition is faster in non-IgE-mediated CMA subjects and in those who received casein hydrolysate with LGG.

Background: Cow milk allergy (CMA) is the most common food allergy in breastfed infants. The aim of this study is to verify whether certain perinatal factors may influence the development of CMA immunoglobulin E (IgE)+. Methods: A retrospective, observational study of case and control groups was carried out. Information was collected of patients with CMA IgE+ from our department during the years 1990-2013. Patients of the same age and sex were recruited for the control group. Information on the following variables was collected: sex, age, pregnancy tolerance, duration of pregnancy, type of delivery, isolated doses of formula feeding in hospital (FFH), duration of breastfeeding, and family history of allergy (defined as ≥1 first-degree family member with allergic disease). Statistical analysis was performed using multivariate logistic regression techniques. Results: A total of 211 cases were included in this study. Multivariate analysis showed an influence of duration of breastfeeding, FFH to be a risk factor (OR 4.94; 95% CI 2.68-9.08), especially in caesarean delivery (OR 11.82; 95% CI 2.64-47.50), and prematurity (OR 0.29; 95% CI 0.09-0.92) to be a protective factor. Conclusions: Perinatal factors play a key role in the development of CMA IgE+, with an influence of breastfeeding duration, FFH and caesarean delivery as risk factors and prematurity as a protective factor. While family history had no important role, environmental factors were more decisive.

Background: Cow milk allergy (CMA) is the most common food allergy in infants. Some patients will express, in the future, other allergic diseases (allergic march). Objective: To evaluate if a new scoring system could determine the risk of developing allergic march. Methods: A retrospective observational cohort study of subjects who were immunoglobulin E (IgE) mediated was conducted. We defined a risk score for atopy (RSA), including clinical and laboratory variables. Three risk groups were defined according to the RSA. We defined as dependent variables atopy (one or more allergic diseases) and atopy+ (two or more allergic diseases). A multivariate logistic regression model was created, which included RSA and the type of formula (high-grade extended hydrolyzed formula [EHF] with Lactobacillus rhamnosus GG (LGG), high-grade EHF without LGG, and other formulas). Results: A total of 211 patients were recruited. When we analyzed the risk of atopy+, we found an increased risk for RSA intermediate-risk (odds ratio [OR 2.08] [95% confidence interval {CI}, 0.95‐4.56) and high-risk (OR 24.74 [95% CI, 6.26‐97.73]) groups, and a decreased risk for the subjects fed with high-grade EHF (OR 0.42 [95% CI, 0.20‐0.87]) and also in those subjects fed with high-grade EHF plus LGG (OR 0.30 [95% CI, 0.09‐0.98]). Conclusion: RSA is a simple and useful tool to predict the risk of developing other allergic diseases in patients with IgE-mediated CMA.