Clinical characteristics, laboratory findings, and tolerance acquisition in infants with cow's milk protein allergy in a private center in Lima, Peru for the period 2021-2022.

BACKGROUND: Cow's milk protein allergy (CMPA) remains relatively understudied in Latin America. METHODS: In this observational study, we enrolled 64 patients with a median age of 3 months, of whom 60% were male. Patients included had a history of IgE-mediated reactions with IgE sensitization or non-IgE-mediated reactions or symptoms following exposure to cow's milk. They underwent skin prick test, ImmunoCAP, fecal calprotectin (FC), and fecal eosinophil-derived neurotoxin (EDN), in addition to double-blinded placebo-controlled oral food challenges (DBPCFC), with clinical evolution and tolerance acquisition observed over 1 year. RESULTS: Malnutrition was present in 78.1% of patients, and 87.5% had a family history of atopy, with 51.6% receiving exclusive breastfeeding. Gastrointestinal manifestations were prevalent in 90.6% of patients, followed by dermatological manifestations (10.9%), with only 2 experiencing anaphylaxis. IgE-mediated CMPA was observed in only six patients. In those with non-IgE-mediated CMPA, FC had a median of 284 mg/dL (IQR: 138.5-415.5), while EDN had a median of 508.5 mg/dL (IQR: 160.25-868). One year after diagnosis, median FC significantly decreased (p < 0.0001), and malnutrition prevalence reduced to 17.1%. Moreover, 81% of patients acquired tolerance following DBPCFC, with 52% utilizing nutritional replacement formulas at diagnosis. Notably, 94% of those extensively hydrolyzed casein-based formulas achieved tolerance (p = 0.08). CONCLUSION: Our findings provide a foundational framework for future investigations into CMPA diagnosis, tolerance acquisition, and the utilization of hypoallergenic formulas tailored to the unique characteristics of our region.

The Use of a Novel Donkey Milk-Derived Human Milk Fortified in the Neonatal Period Had No Effect on the Frequency of Allergic Manifestations During the First Years of Life: The "Fortilat Trial" Follow-Up.

Background: Since human milk contents does not meet the high need of very low birth weight infants, fortification of breast milk is a standard practice for this population. As donkey milk has been long considered for children allergic to cow's milk proteins due to its low allergic properties, a new donkey milk-derived fortifier (DF) has been recently evaluated as a valid alternative to bovine milk-derived fortifier (BF). It seems to improve feeding tolerance when compared with standard BF, with similar neurodevelopmental and auxological outcome at 18 months of age. The aim of this study is to evaluate the development of allergic manifestations occurring in the population of the "Fortilat Trial" at 6-8 years of age. Methods: Allergic manifestations were assessed by an ad hoc questionnaire administered to families. The occurrence of asthma, allergic rhinitis and oculorhinitis, rashes and atopic dermatitis, food allergies, accesses to an emergency department for allergic reactions, and the need of antihistamine have been investigated. Results: In total, 113 infants were enrolled in the study (BF arm: n = 60, DF arm: n = 53). No difference in risk was observed between the two groups for all the considered outcomes. In conclusion, our data suggest that DF does not impact the development of allergic manifestations in the first years of life. Clinical Trial Registration number: ISRCT N70022881.

[Association of pregnancy factors with cow's milk protein allergy in infants].

OBJECTIVE: To preliminarily explore the association of pregnancy factors with cow's milk protein allergy in infants. METHODS: This study was based on data from a subcohort of a study called genetic susceptibility to cow's milk allergy in Chinese children, including infants born in Peking University People's Hospital between March 1, 2020, and December 31, 2020. The infants were divided into a cow's milk protein allergy (CMPA) group and a control group according to whether they had developed cow's milk protein allergy at the age of 1 year. We retrospectively collected the clinical data of infants and their mothers before and during pregnancy, and analyzed the association of multiple factors during pregnancy with cow's milk protein allergy in infants. RESULTS: A total of 278 infants were enrolled in this study, including 52 infants with CMPA and 226 infants without CMPA. Among them, there were 143 boys and 135 girls. The proportion of male infants in the CMPA group (69.2%) was higher than that in the control group (47.3%), and the difference was statistically significant (P=0.004). There were no significant differences in the distribution of birth weight, gestational age at birth, low-birth-weight infants, premature, umbilical cord entangle neck, and neonatal asphyxia between the CMPA group and the control group (P>0.05). The proportion of mothers complicated with autoimmune diseases, anemia or antibiotics exposure during pregnancy in the CMPA group was higher than that in the control group, and there were statistical differences between the two groups (P < 0.05). There was no significant difference in the distribution of other pregnancy complications between the two groups (P>0.05), such as eclampsia/preeclampsia, chronic hypertension/gestational hypertension, diabetes/gestational diabetes, thyroid diseases, and so on. There was no significant difference in the overall distribution of some blood routine indexes during pregnancy between the CMPA group and the control group (P>0.05). Multivariate Logistic regression analysis showed that male infant, mothers complicated with autoimmune diseases or anemia, antibiotic exposure during pregnancy were independent risk factors for cow's milk protein allergy. CONCLUSION: Male infant, mothers complicated with autoimmune diseases or anemia, antibiotic exposure during pregnancy were independent risk factors for cow's milk protein allergy.

Alergia a la leche de vaca: ¿se pueden evitar las pruebas de provocación oral? Un análisis probabilístico basado en datos clínicos / Cow's milk allergy: Can oral food challenges be avoided? A probabilistic analysis based on clinical data

Introducción. La prueba de provocación oral (PPO) para el diagnóstico de alergia a las proteínas de la leche de la vaca (APLV) presenta riesgos y requiere de recursos. Nuestro objetivo fue evaluar condiciones y pruebas complementarias para identificar una alta probabilidad de APLV. Población y métodos. Análisis secundario sobre estudio de pacientes atendidos en una unidad de alergia entre 2015 y 2018. Se determinaron las probabilidades prepruebas asociadas a los síntomas y sus combinaciones, y las probabilidades pospruebas luego de realizadas pruebas cutáneas y determinación de inmunoglobulina E (IgE) sérica. Resultados. Se evaluó la información de 239 pacientes. Se observaron probabilidades mayores al 95 % en pacientes con angioedema y combinación de urticaria y vómitos. Usando puntos de corte propuestos por Calvani et al., la combinación de vómitos con rinitis, sin angioedema, también superó el 95 %. Conclusión. Se ofrece una metodología para identificar pacientes en los que puede diagnosticarse APLV sin realización de PPO.

Introduction. The oral food challenge (OFC) for the diagnosis of cow's milk protein allergy (CMPA) poses risks and requires resources. Our objective was to assess conditions and complementary tests used to identify a high probability of CMPA. Population and methods. Secondary analysis of a study of patients seen at a unit of allergy between 2015 and 2018. Pre-testing probabilities associated with symptoms and their combinations and post-testing probabilities after skin prick testing and serum immunoglobulin E (IgE) levels were determined. Results. The data from 239 patients were assessed. A probability greater than 95% was observed for angioedema and a combination of urticaria and vomiting. Based on the cut-off points proposed by Calvani et al., the combination of vomiting with rhinitis, without angioedema, also exceeded 95%. Conclusion. A methodology is provided to identify patients in whom CMPA may be diagnosed without an OFC.

[Prevalencia alergia a proteína leche de vaca con escala COMISS, IMPE Chihuahua, marzo a mayo 2022, serie de casos].

Objective: To know the prevalence of CMPA with the scale in patients of the pediatrics external consultation in the Municipal Institute of Pension of Chihuahua in period from march to may 2022, Series of cases. Methods: A search was carried out on CMPA consultations in the period from March to May 2022, permission and informed consent was requested to access the clinical file and retrospectively, an analytical, observational, non- experimental, descriptive study was carried out., the COMISS scale was applied, and formulated a series of cases. Results: The prevalence of CMPA is 0.3%. CMPA positive patients did not have statistically significant differences with the suspects in terms of age, gestational age, birth weight, maternal age, atopy or tobacco. Presenting a series of cases. Conclusions: The prevalence of CMA with the use of COMISS was 0.3%, lower than the prevalence worldwide. The wider use of this scale is suggested to be considered in order to achieve a more accurate diagnosis.

Objetivo: Conocer la prevalencia de la APLV con la escala CoMISS en pacientes de la consulta externa de pediatria en el instituto municipal de pensiones de chi- huahua. en el periodo de marzo a mayo 2022, serie de casos. Métodos: Se realizó una búsqueda sobre las consultas de APLV en el periodo de marzo a mayo 2022, se solicitó el permiso y consentimiento informado para acceder al expediente clínico y de manera retrospectiva, se realizó estudio analítico, observacional, no experimental, descriptivo, se aplicó la escala COMISS, y formulando serie de casos. Resultados: La prevalencia de APLV es de 0.3%, Los pacientes positivos APLV no tuvieron diferencias estadisticamente significativas con los sospechosos en cuanto a edad, edad gestacional, peso al nacer, edad de la madre, atopia o tabaco. Presentando una serie de casos. Conclusiones: la prevalencia de APLV con el uso de COMISS fue del 0.3%, menor a la prevalencia a nivel mundial. Se sugiere el uso más amplio de esta escala para considerar esta patología y lograr un diagnóstico más certero.

A Review of the Risk of Cow's Milk Protein Allergy in Oral Medication.

Immunoglobulin E (IgE)-mediated cow's milk allergy (CMA) is a common food reaction resulting from the consumption of cow's milk protein (CMP). The clinical manifestations of CMA include mild to severe urticaria, skin-manifested hypersensitivity reactions, and anaphylaxis. Food allergies may affect 8% of children and 10% of adults. The Federal Food, Drug, and Cosmetic Act (FD&C Act) requires that the label of a food must declare the presence of a "major food allergen" (MFA) contained in the food or ingredient. The Food and Drug Administration (FDA) generally regards milk protein concentrate (MPC) as safe for human consumption and use. The increasing use of MPC in formulations raises the need for its revelation in prescription and on labels of over-the-counter drugs. This review investigates oral and topical (including mucosal) preparations containing MPC for dermatologic and other uses and their therapeutic impact. Our findings suggest that for the adult population, the risk of serious cow's milk protein allergy (CMPA) from medications is minimal.

Nutritional Strategies for the Prevention and Management of Cow's Milk Allergy in the Pediatric Age.

Cow's milk allergy (CMA) is one of the most common pediatric food allergies. The prevalence and severity of CMA have increased dramatically in the last decades, under the pressure of environmental factors in genetically predisposed individuals. Among the environmental influences, nutritional factors play a crucial role. Diet is the most modifiable factor, representing a potential target for the prevention and treatment of CMA. In this review, we report the most scientific-based nutritional strategies for preventing and managing pediatric CMA. In addition, we propose the most complete supplement of compounds able to prevent nutrient deficiencies in CMA pediatric patients and to positively influence the disease course.

Formula milk companies and allergy healthcare professionals in India.

India is a low-middle income country with a population of 1.4 billion and home to one quarter of the world's children. Exclusive breastfeeding until 6 months and continued breastfeeding until at least 2 years as per global recommendations are common practice. The Indian government and associated organisations have strived to protect breastfeeding, which is important in a country with high under-5 mortality, malnutrition and stunting. Allergic disease is under-recognised in India, but despite the absence of a dedicated allergy medical specialty, awareness of allergy is increasing among healthcare practitioners and in the general population. In high-income countries, overdiagnosis of allergy has become recognised as an issue in recent years. Allergy healthcare professionals have also attracted criticism for close relationships with the formula industry, which appear to have contributed to excessive use of specialised formula products and undermining of breastfeeding. Specialised formula has been used unnecessarily for preventing allergy, based on fraudulent and selectively reported science; and for managing normal infant symptoms which are mislabelled as milk allergy. This forms part of a broader formula industry corporate strategy to widen the boundaries of illness in order to expand sales and markets. In India, allergic disease management is hindered by limited understanding of the disease entity among practitioners, low access to diagnostics, limited healthcare resources, high exposure to air pollution and a large, diverse population. Data specific to India on allergic disease prevalence and interpreting allergy diagnostics are incomplete. The knowledge gaps mean allergy management in India is often extrapolated from guidance developed in high-income countries with low breastfeeding rates. As the allergy specialty develops in India, local guidance and practice will need to recognise the threat that current allergy practice poses to India's normative infant feeding culture, and ensure that breastfeeding continues to be supported at all levels.

Cow's milk allergy: Can oral food challenges be avoided? A probabilistic analysis based on clinical data. / Alergia a la leche de vaca: ¿se pueden evitar las pruebas de provocación oral? Un análisis probabilístico basado en datos clínicos.

Introduction. The oral food challenge (OFC) for the diagnosis of cow's milk protein allergy (CMPA) poses risks and requires resources. Our objective was to assess conditions and complementary tests used to identify a high probability of CMPA. Population and methods. Secondary analysis of a study of patients seen at a unit of allergy between 2015 and 2018. Pre-testing probabilities associated with symptoms and their combinations and post-testing probabilities after skin prick testing and serum immunoglobulin E (IgE) levels were determined. Results. The data from 239 patients were assessed. A probability greater than 95% was observed for angioedema and a combination of urticaria and vomiting. Based on the cut-off points proposed by Calvani et al., the combination of vomiting with rhinitis, without angioedema, also exceeded 95%. Conclusion. A methodology is provided to identify patients in whom CMPA may be diagnosed without an OFC.

Introducción. La prueba de provocación oral (PPO) para el diagnóstico de alergia a las proteínas de la leche de la vaca (APLV) presenta riesgos y requiere de recursos. Nuestro objetivo fue evaluar condiciones y pruebas complementarias para identificar una alta probabilidad de APLV. Población y métodos. Análisis secundario sobre estudio de pacientes atendidos en una unidad de alergia entre 2015 y 2018. Se determinaron las probabilidades prepruebas asociadas a los síntomas y sus combinaciones, y las probabilidades pospruebas luego de realizadas pruebas cutáneas y determinación de inmunoglobulina E (IgE) sérica. Resultados. Se evaluó la información de 239 pacientes. Se observaron probabilidades mayores al 95 % en pacientes con angioedema y combinación de urticaria y vómitos. Usando puntos de corte propuestos por Calvani et al., la combinación de vómitos con rinitis, sin angioedema, también superó el 95 %. Conclusión. Se ofrece una metodología para identificar pacientes en los que puede diagnosticarse APLV sin realización de PPO.

Associations between functional constipation and non-IgE-mediated food allergy in infants and children.

BACKGROUND: The non-IgE-mediated food allergy (non-IgE-FA) is less prevalent than IgE-mediated food allergy, and their relationship with functional constipation (FC) needs to be clarified. METHODS: A total of 305 infants and children with constipation treated in the Department of Pediatric Gastroenterology, Children's Hospital of Nanjing Medical University, from July 2020 to December 2021 were included in this study. Four cases with organic lesions were excluded. Among 301 diagnosed with FC, according to ROME IV criteria, 81 cases with allergy-related indicators were further evaluated for food allergy by food-specific IgG antibody test, allergen- specific IgE antibody detection, skin prick test, and food avoidance and reintroduction. RESULTS: A total of 45 cases with FC were diagnosed with food allergy, and the incidence rate was 15%. Among the 45 patients, 35 cases (77.8%) had FC with non-IgE-FA. The main clinical symptoms or signs included anal fissure, abdominal pain, and pain during defecation. The most prevalent allergic foods were cow's milk, eggs, fish, and shrimp. Ten (22.2%) cases reported FC with mixed food allergy, including both non-IgE-mediated and IgE-mediated food allergy. This study focused on non-IgE-mediated food allergy-related FC. CONCLUSION: Our results showed that the incidence of food allergy in infants and children with FC was 15%, which was mainly mediated by non-IgE-FA. The main clinical symptoms or signs in these cases included anal fissure, abdominal pain, and pain during defecation, and the main allergens included milk, eggs, fish, and shrimp.

Case report: Pneumatosis in a neonate with thrombocytopenia absent radius syndrome.

BACKGROUND: Thrombocytopenia absent radius (TAR) syndrome is a rare disease with an estimated prevalence of one in 200,000 live births. TAR is associated with cardiac and renal anomalies as well as gastrointestinal problems such as cow's milk protein allergy (CMPA). Typically neonates with CMPA present with mild intolerance, with few reports in the literature of more severe intolerance resulting in pneumatosis. We present a case of a male infant with TAR syndrome who developed gastric and colonic pneumatosis intestinalis. CASE DESCRIPTION: An eight-day-old male infant born at 36 weeks gestation with a diagnosis of TAR, presented with bright red blood in his stool. At this time he was on full formula feeds. Given continued bright red blood within his stool, an abdominal radiograph was obtained which was consistent with colonic and gastric pneumatosis. A complete blood count (CBC) was notable for worsening thrombocytopenia, anemia and eosinophilia. Once enteral feeds were held there was rapid resolution of the radiographic findings and resolution of his bloody stool. He was ultimately diagnosed with a CMPA. CONCLUSION: Though there are reports of CMPA in patients with TAR, the severity of this patient's presentation with both colonic and gastric pneumatosis is unique. Without the knowledge of the association of CMPA with TAR, this case could have been misdiagnosed and led to reintroduction of cow's milk containing formula, resulting in further complications. This case highlights the importance of a timely diagnosis and severity of CMPA in this population.

Cow's milk allergy in children impacts parental or caregiver calcium intake.

Food allergies have become a global epidemic, affecting more than 10% of the population and 8% of children worldwide. Eliminating or limiting a food group from the diet can adversely impact micronutrient consumption. Milk allergies can impact the amount of calcium consumed in the diet, serving as a barrier to meeting daily calcium needs. Previous research evaluates the nutritional impact food allergies may have on children diagnosed with food allergies; however, there is a marked gap in literature that investigates the impact that children's allergy may have on their parent or caregiver. We hypothesized that milk elimination in a child's diet resulting from a milk allergy is associated with inadequate calcium intake among parents. Study participants (n = 55) lived in the United States and included parents or caregivers of a child with a diagnosed milk allergy (experimental group) and parents of a child without a milk allergy (control group). Calcium intake was estimated by using the validated Calcium Assessment Tool. Results demonstrated that the experimental group consumed significantly less calcium (273 mg/d) than the control group (520 mg/d; P < .01). Notably, both groups consumed inadequate calcium relative to the calcium Recommended Dietary Allowance for adults of 1000 mg/d, although calcium supplementation was not assessed in this study. Key findings from this study indicate widespread inadequate dietary calcium intake and suggest a need for increased calcium consumption in this population.

Early, continuing exposure to cow's milk formula and cow's milk allergy: The COMEET study, a single center, prospective interventional study.

BACKGROUND: Cow's milk allergy (CMA) is a common food allergy among infants. Information regarding the best timing for first exposure to cow's milk formula (CMF) is controversial and more evidence is required. Few randomized control trials have tried to accurately assess the timing and preventive effect of exposure to CMF on small cohorts. OBJECTIVE: This study assessed the association between early, continuing exposure to CMF on the basis of the parents' preferences and the development of immunoglobulin E (IgE)-mediated CMA in a large birth cohort. METHODS: Newborns were prospectively recruited shortly before birth and divided into 2 groups according to parental feeding preference for the first 2 months of life: (1) exclusive breastfeeding (EBF); or (2) at least 1 meal of CMF (with or without breastfeeding) daily. Infants were followed up monthly until the age of 12 months. RESULTS: Among 1992 infants participating in the study, 1073 (53.86%) were in the EBF group until 2 months of age. IgE-mediated CMA was confirmed in 0.85% (n = 17); all were in the EBF group. Within this group, the prevalence of IgE-mediated CMA was 1.58% compared with 0 in the other groups (relative risk, 29.98; P < .001). Post hoc analysis revealed IgE-mediated CMA prevalence of 0.7% in the per-protocol EBF group vs 3.27% among breastfed infants who were exposed to a small amount of CMF during the first 2 months of life. A family atopic background did not affect the results. CONCLUSION: Early, continuing exposure to CMF from birth has the potential to prevent the development of IgE-mediated CMA and should be encouraged. However, the exposure needs to be consistent because occasional exposure increases the risk of developing IgE-mediated CMA and should be avoided.

Effects of regular soy formula intake between 1 and 2 months of age on food sensitization in infancy.

BACKGROUND: The effects of regular soy formula (SF) intake on the development of food sensitization in infancy remain unclear. This study aimed to assess the effects of regular SF intake between 1 and 2 months of age on food sensitization development by 6 months of age. METHODS: Using data from a randomized controlled trial of a birth cohort from four Japanese hospitals that assessed cow's milk allergy development, we performed a retrospective cohort study of 235 infants who avoided cow's milk formula and supplemented breastfeeding with SF as required between 1 and 2 months of age. Regular SF intake was defined as SF consumption of ≥14 days per month and ≥1350 ml per month. Food sensitization was defined as positive skin prick test reactions to hen's egg, cow's milk, wheat, and/or soy. Using multivariable logistic regression models that adjusted for parental, perinatal, and environmental factors, we calculated the adjusted odds ratios of regular SF intake for food, hen's egg, and cow's milk sensitization by 6 months of age. RESULTS: From the 235 participants, 114 (48.5%) had regular SF intake. The adjusted odds ratios of regular SF intake for food, hen's egg, and cow's milk sensitization were 0.32 (95% confidence interval: 0.16-0.62, p = .0007), 0.42 (0.20-0.88, p = .02), and 0.33 (0.14-0.81, p = .02), respectively. CONCLUSION: Regular SF intake between 1 and 2 months of age in infants avoiding cow's milk formula was significantly associated with a reduced risk of food sensitization in infancy.

Updated full range of Eliciting Dose values for Cow's milk for use in food allergen risk assessment.

Access to Eliciting Doses (ED) for allergens enables advanced food allergen risk assessment. Previously, the full ED range for 14 allergenic foods, including milk, and recommendations for their use were provided (Houben et al., 2020). Additional food challenge studies with cow's milk-allergic patients added 247 data points to the original dataset. Using the Stacked Model Averaging statistical method for interval-censored data on the 697 individual NOAELs and LOAELs for milk generated an updated full ED distribution. The ED01 and ED05, the doses at which 1% and 5% of the milk-allergic population would be predicted to experience any objective allergic reaction, were 0.3 and 3.2 mg milk protein for the discrete and 0.4 mg and 4.3 mg milk protein for the cumulative dose distribution, respectively. These values are slightly higher but remain within the 95% confidence interval of previously published EDs. We recommend using the updated EDs for future characterization of risks of exposure of milk-allergic individuals to milk protein. This paper contributes to the discussion on the Reference Dose for milk in the recent Ad hoc Joint FAO/WHO Expert Consultation on Risk Assessment of Food Allergens. It will also benefit harmonization of food allergen risk assessment and risk management globally.

Timing of Cow's Milk Protein Introduction and Childhood Adverse Reactions to Cow's Milk.

BACKGROUND: Current guidelines emphasize early introduction to potentially allergenic foods, but the optimal timing, amount, and exposure routes for foods other than peanut are not well-established. Cow's milk is often the first allergenic food introduced through infant formulas. OBJECTIVE: To examine timing of cow's milk protein introduction (CMPI), including interaction with formula supplementation after delivery, in relation to reported cow's milk adverse reactions throughout childhood. METHODS: Among children in the Boston, Mass-area Project Viva cohort, we assessed timing of CMPI (<2 weeks, 2 weeks-<6 months, ≥6 months) with questionnaires administered in infancy. Outcomes were (1) parent-reported cow's milk adverse reactions via annual questionnaires from age 2 to 13 years (n = 1298) and (2) milk sensitization (n = 505) and IgE-mediated milk allergy (n = 491) at age approximately 8 years. We used multivariable logistic regression models adjusted for parental atopy history, delivery mode, gestational age at delivery, child race, and census tract median household income, and investigated effect modification by ever/never breast-fed status and formula supplementation in the delivery hospital. RESULTS: A total of 32% were introduced to cow's milk protein at age less than 2 weeks, 38% at age 2 weeks to less than 6 months, and 30% at age 6 months or more. Compared with children with CMPI at age less than 2 weeks, children with CMPI at age 6 months or more had a higher risk of cow's milk adverse reaction at age 2 to 5 years (odds ratio, 2.4 [1.2-4.7]). Children given formula after delivery + CMPI at age less than 2 weeks had the lowest risk overall. Among children not given formula after delivery, CMPI at age 2 weeks to 6 months appeared most protective. Results were similar among ever-breast-fed children. Timing of CMPI was not associated with milk sensitization or IgE-mediated milk allergy in mid-childhood. CONCLUSIONS: Early, consistent cow's milk exposure appears protective against adverse reactions to cow's milk.

Relevance of Early Introduction of Cow's Milk Proteins for Prevention of Cow's Milk Allergy.

Food allergy incidence has increased worldwide over the last 20 years. For prevention of food allergy, current guidelines do not recommend delaying the introduction of allergenic foods. Several groundbreaking studies, such as the Learning Early About Peanut Allergy study, showed that the relatively early introduction of this allergenic food between 4-6 months of age reduces the risk of peanut allergy. However, less is known about the introduction of cow's milk, as many children already receive cow's-milk-based formula much earlier in life. This can be regular cow's milk formula with intact milk proteins or hydrolyzed formulas. Several recent studies have investigated the effects of early introduction of cow's-milk-based formulas with intact milk proteins on the development of cow's milk allergy while breastfeeding. These studies suggest that depending on the time of introduction and the duration of administration of cow's milk, the risk of cow's milk allergy can be reduced (early introduction) or increased (very early introduction followed by discontinuation). The aim of this narrative review is to summarize these studies and to discuss the impact of early introduction of intact cow's milk protein-as well as hydrolyzed milk protein formulas-and the development of tolerance versus allergy towards cow's milk proteins.