Milk Allergy in Infants: What You Should Know

Milk allergy in infants is usually a self-resolving condition. Keep reading to learn more about this condition that affects 3% of children.
Milk Allergy in Infants: What You Should Know
Maria del Carmen Hernandez

Reviewed and approved by the dermatologist Maria del Carmen Hernandez.

Last update: 18 May, 2023

Milk allergy in infants is a fairly common condition. It’s actually an allergic reaction to the protein found in milk. This allergy’s characterized by the presence of different signs and symptoms in the baby and may reappear at the age of 6 years. It’s ideal to diagnose it early to avoid the nutritional deficiency that it usually causes if not treated properly.

What causes milk allergy in babies?

Allergies to certain foods are generated by the immune system of people. That is, when little ones are allergic to milk, the immune system reacts to a specific protein and triggers a response to neutralize it. Then, when the body comes in contact with the protein again, the response will be recognized and chemicals will be released that cause the symptoms and signs of milk allergy in infants. In most cases, sensitivity is triggered to both caseins and whey proteins.

Symptoms of milk allergy in infants

In general, clinical manifestations appear during the first months of life, especially before the age of six months. The first symptoms occur in the days or weeks after ingestion of milk protein. In addition, adverse reactions to food fall into two main categories:

  1. IgE-mediated: These are rapid-onset reactions, where symptoms appear one hour after ingestion.
  2. Non-IgE mediated: These are slow-onset reactions, which are the most frequent causes of this type of allergy, where symptoms take hours or days to be expressed
A baby that has vomited.
Vomiting, hives, or pruritus, among others, are some symptoms that can appear rapidly as a result of infant milk allergy.

Rapid onset symptoms

According to a review in the Italian Journal of Pediatrics, symptoms that appear rapidly in infants may include the following:

  • Wheezing
  • Urticaria
  • Itching or tingling sensation around the lips or mouth
  • Vomiting
  • Angioedema (swelling of the tongue, throat, or lips)
  • Anaphylaxis

You may be interested in: Chronic Hives in Children

Slow onset symptoms

Slow-onset symptoms may include the following:

  • Colic
  • Diarrhea
  • Refusal to eat
  • Irritability
  • Abdominal cramps
  • Blood in the stool

Diagnosis of milk allergy in infants

Currently, there’s no specific test for milk allergy in infants. However, the diagnosis focuses on the history of symptoms and a corresponding physical examination. Skin prick tests or specific serum IgE s how high sensitivity but low specificity. Therefore, it can sometimes be positive in non-allergy sufferers.

Managing milk allergy in infants

The definitive treatment for any food allergy is the elimination of that product from the daily diet, according to a review by the European Journal of Pediatrics. In general, milk allergy tends to disappear on its own when the child is between 3 and 5 years old. However, it’s best to limit the amount of dairy the mother consumes, as the protein contained can also cause reactions through breast milk.

A mother breastfeeding her baby.
Breastfeeding is the best source of nutrition for newborns. It also contributes to the prevention of allergic reactions.

Alternatives to milk for breastfeeding infants

There are different feeding options for infants with milk allergy, such as breastfeeding. In this way, allergic reactions triggered by this food can be prevented.

  • Breastfeeding: This is the most recommended nutritional source for babies. In fact, it’s always advisable to breastfeed for as long as possible.
  • Hypoallergenic formulas: This type of formulation has enzymes responsible for hydrolyzing the milk proteins that cause allergic reactions, such as whey and casein. They’re also known as elemental formulas.
  • Soy-based formulas: These are made with soy protein as a replacement for milk protein. Allergic reactions sometimes occur with this formulation.
  • Artificial milks based on amino acids: These are made with the simplest form of proteins and amino acids. They’re recommended when hypoallergenic formulations fail to improve the clinical picture of milk allergy in infants.

Babies and allergies

Milk protein allergy is one of the most common allergies in babies. It’s even one of the first to manifest itself, which is beneficial for its early detection. In case of any doubt or concern, it’s always best to consult a pediatrician who will make an accurate diagnosis and indicate the measures to be implemented.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Lifschitz C, Szajewska H. Cow’s milk allergy: evidence-based diagnosis and management for the practitioner. Eur J Pediatr. 2015 Feb;174(2):141-50. doi: 10.1007/s00431-014-2422-3. Epub 2014 Sep 26. PMID: 25257836; PMCID: PMC4298661.
  • Bartuzi Z, Cocco RR, Muraro A, Nowak-Węgrzyn A. Contribution of Molecular Allergen Analysis in Diagnosis of Milk Allergy. Curr Allergy Asthma Rep. 2017 Jul;17(7):46. doi: 10.1007/s11882-017-0716-z. PMID: 28597347.
  • Caffarelli C, Baldi F, Bendandi B, Calzone L, Marani M, Pasquinelli P; EWGPAG. Cow’s milk protein allergy in children: a practical guide. Ital J Pediatr. 2010 Jan 15;36:5. doi: 10.1186/1824-7288-36-5. PMID: 20205781; PMCID: PMC2823764.
  • Cuomo B, Indirli GC, Bianchi A, Arasi S, Caimmi D, Dondi A, La Grutta S, Panetta V, Verga MC, Calvani M. Specific IgE and skin prick tests to diagnose allergy to fresh and baked cow’s milk according to age: a systematic review. Ital J Pediatr. 2017 Oct 12;43(1):93. doi: 10.1186/s13052-017-0410-8. PMID: 29025431; PMCID: PMC5639767.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.