Milk casein allergy: symptoms, what to do?

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  1. Milk casein allergy
  2. Definition: what is casein?
  3. In which milks is it present?
  4. Symptoms in case of allergy
  5. Infant milk allergy
  6. Adult casein allergy
  7. Diagnosis
  8. What to do in case of allergy?
  9. You may be interested:

Milk casein allergy

Casein is a protein found in cow, goat and sheep's milk. Some people are allergic to it and experience vomiting, coughing and even hives when consuming dairy products.

What are the warning symptoms in adults? What are the tests to be performed and what are the treatments to alleviate them?

milk casein

Photo Adonyi Gábor in Pexels

Definition: what is casein?

Representing about 75-80% of milk proteins, casein is one of the main proteins of cow, goat or sheep milk.

In case of allergy, the immune system, which usually produces antibodies to protect itself, this time produces antibodies that bind to the casein and induce excessive reactions in the body (coughing, itching, edema, coughing, breathing difficulties, discomfort, digestive disorders) "Casein is not the only source of allergy in milk.

It is often the cause and is usually the most serious, but not necessarily exclusively, as serum proteins can cause the same type of symptoms.

More than an allergy to milk casein, we are talking about an allergy to milk proteins," prefers Dr. Martine Morisset, an allergist at CHU d'Angers.

In which milks is it present?

Casein is present in all animal milks, as well as in breast milk. "But there is still a difference between casein that comes from breast milk and casein that comes from cow's milk," says the allergist.

It is possible to produce antibodies (IgE) that do not recognize maternal casein but will recognize proteins from other mammalian milks:

"It is important to know that the caseins in cow's, sheep's or goat's milk are very close and therefore, if you are allergic to one, you are most likely allergic to the others", adds the specialist.

Caution, some products contain cow's milk proteins such as certain industrial hams or salmon reconstituted with these proteins.

Symptoms in case of allergy

There are two types of reactions:

Immediate IgE-mediated allergy that causes acute manifestations: cough, hives, abdominal pain, vomiting and even angioedema that can sometimes lead to anaphylactic shock with loss of consciousness.

Non-IGE mediated allergy, which manifests itself several hours after milk intake. In theory, these types of allergies are less severe. They cause gastrointestinal symptoms such as gastroesophageal reflux, chronic diarrhea, swelling, or abdominal pain.

A baby who does not gain weight may have a casein allergy.

Infant milk allergy

In babies, this allergy often appears at weaning (cessation of breastfeeding), as soon as the first bottles are given.

In some delayed forms called SEIPA, some babies repeatedly vomit for one to four hours after taking a bottle.

"An allergy to milk protein is also thought to occur when a baby does not gain weight, has chronic diarrhea, rectorrhea (blood in the stool), or has severe atopic dermatitis (eczema)," the allergist lists.

Adult casein allergy

Most of these allergies heal spontaneously. "At the age of 2, 25%-30% are still allergic. 0.5% will still be allergic after the age of 15," explains Dr. Morisset.

The images are often identical to those of the child. "There are also other digestive forms that occur in both babies and adults, such as esophagitis -inflammation of the esophagus- which is sometimes revealed by food remaining blocked in the esophagus," the specialist continues.


It is carried out by questioning the clinical symptoms and skin tests (puncture) with cow, goat or sheep milk, as well as an IgE assay in the milk of the mammal in question.

What to do in case of allergy?

In case of allergy, you should first consult a pediatrician or general practitioner who will prescribe a blood test to measure IgE. In a second step, tests can be done in the allergist: this specialist will put small drops of milk on the child's skin.

If a small, red, itchy papule appears where the milk drop was deposited, the allergy is very suspicious. "In case of late allergy, the allergist applies a test that he will read after 48 to 72 hours (milk patch test) to confirm the diagnosis.

In addition, in case of proven allergy, the consumption of dairy products is suspended. The babies, breastfeeding is resumed or replaced by advanced hydrolysates of cow's milk protein or mixtures of amino acids or hydrolysates of rice protein.

These formulas are perfectly adapted to ensure the growth of a young child.

We will then follow the child, check that he or she is doing well with this substitute, and at some point check if conditions are conducive to the reintroduction of cow's milk proteins.

To do this, we will take a new blood sample, do skin tests, and if markers such as milk protein IgE (and not IgG, which has no scientifically proven value) have decreased, we will propose reintroducing the milk under medical supervision," says Dr. Klaus.

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