Brief overview
- Description: Hypersensitivity reaction of the immune system to proteins in cow’s milk, which may vary in severity.
- Symptoms: e.g. skin rash, gastrointestinal symptoms, respiratory symptoms, rarely allergic shock; symptoms often appear immediately, sometimes with a time delay.
- Treatment: avoidance of cow’s milk and products made from it (to an individually appropriate extent – nutritional counseling advisable!); emergency medication if necessary.
- Diagnosis: Consultation with a physician, ingestion of cow’s milk under medical observation, skin test, blood tests.
- Causes and risk factors: presumably inherited allergy, too early intake of cow’s milk and altered intestinal flora.
What is cow’s milk allergy?
People with cow’s milk allergy (CMA) – also called cow’s milk protein allergy (CMPA) – are allergic to proteins in cow’s milk.
The first time the immune system comes into contact with an allergen, sensitization occurs: the immune system classifies the allergen as dangerous. On the next contact, it then takes massive action against it: The affected person shows an allergic reaction to the allergen for the first time – in the case of cow’s milk allergy, to the proteins it contains.
Milk proteins from other mammals, such as those in goat’s or mare’s milk, also have the potential to trigger allergies.
Cow’s milk allergy or lactose intolerance?
Lactose intolerance, on the other hand, is not an allergy (the immune system is not involved here). Instead, those affected lack a sufficient amount of the enzyme that the body needs to digest milk sugar: lactase. This enzyme breaks down the milk sugar (lactose) in the small intestine. The resulting building blocks can then be absorbed into the blood via the intestinal wall.
Read more about this form of food intolerance in the article Lactose intolerance.
Cow’s milk allergy mostly affects babies and toddlers
The most common form of cow’s milk intolerance in babies and children under the age of three is cow’s milk allergy. Overall, about two to three percent of the infant and toddler population is affected.
Cow’s milk allergy often ends in the third year of life, because the child’s body then tolerates the milk proteins.
From the age of six, the incidence of cow’s milk allergy drops to less than one percent. Only a few adults are affected by this allergy: it is either newly developed in adulthood or has existed since childhood. However, it is much more common for adults to be unable to tolerate cow’s milk due to lactose intolerance.
The symptoms of cow’s milk allergy are very diverse. The symptoms can vary considerably in type and severity.
Often a cow’s milk allergy manifests itself as a skin rash. The baby develops skin redness, itching and wheals (hives). Neurodermatitis (atopic dermatitis) may reappear or worsen.
Also possible are sudden swellings in the face (angioedema), for example in the area of the lips or larynx.
Occasionally, a cow’s milk allergy causes symptoms in the baby’s respiratory tract, such as allergic rhinitis, cough or asthmatic complaints.
Very rarely, the intake of cow’s milk protein causes severe allergic shock (anaphylactic shock) with respiratory distress and circulatory arrest) in affected individuals.
How quickly do cow’s milk allergy symptoms appear?
They mostly affect the skin and gastrointestinal tract, for example in the form of hives, lip swelling, angioedema, bloody stools, diarrhea or vomiting. Occasionally, symptoms appear in the respiratory tract. Rarely, IgE-mediated symptoms result in anaphylactic shock.
The main symptoms here are gastrointestinal symptoms such as vomiting or spitting up (reflux), colic, diarrhea, constipation or bloody stools.
In addition, a baby with cow’s milk allergy may have impaired growth (failure to thrive).
How to treat cow’s milk allergy?
As with other allergies, contact with the triggering allergen (cow’s milk protein) must be avoided in the case of a cow’s milk allergy.
In the case of cow’s milk allergy, a consultation with a nutritionist experienced in allergology is advisable. In this way, an individually suitable menu can be created, in the case of children in adaptation to the age-dependent nutritional requirements.
Special baby food
For affected infants, this means: Normal infant food (usually consisting of cow’s milk) is taboo for them. Instead, they receive a therapeutic special food:
- Amino acid formulas: If cow’s milk allergy causes severe symptoms in the baby (especially in the digestive tract), special formulas containing only the building blocks of proteins (amino acids) may be useful.
Not suitable in case of cow’s milk allergy
In partially hydrolyzed infant formula, the protein contained is partially broken down. It is generally not suitable for babies with cow’s milk allergy. However, if a child does tolerate it, it can certainly be used.
Goat’s and sheep’s milk are also not suitable for treating cow’s milk allergy. The proteins they contain are similar to those in cow’s milk.
Cereal and other plant-based drinks (such as oat, rice or almond milk) are also not suitable substitutes for cow’s milk.
Cow’s milk allergy in breastfed babies
The consultant can give tips on how the woman can still meet her nutritional needs, for example with regard to calcium (see below). It may also be necessary to take nutritional supplements.
Weaning is very rarely necessary in children with cow’s milk allergy.
Individual tolerance determines the menu
From the introduction of complementary food in children with cow’s milk allergy, it is important to find the appropriate menu.
- Casein
- Milk protein
- Whey
- animal protein
However, a strict renunciation is often not necessary at all. Many children with cow’s milk allergy tolerate cow’s milk in baked form: Dairy products that have been heated to at least 180 degrees Celsius for at least 30 minutes during processing are often not a problem. The high temperature changes the allergenic milk proteins in such a way that they do not trigger any allergic reaction or only a milder one.
With the help of a doctor, it is therefore necessary to find out whether a person allergic to cow’s milk can tolerate certain dairy products in a certain quantity. These tolerable quantities should be regularly included in the diet in consultation with the doctor or nutritionist. This can promote the development of tolerance to milk protein in the affected person.
It also makes the personal menu more varied and makes the other ingredients of cow’s milk accessible to the affected person (such as calcium).
Which foods are particularly suitable as an alternative to cow’s milk and products (cheese, yogurt, etc.) so that important nutrients are not missing? The answer to this question is relevant on the one hand for breastfeeding mothers who have to do without milk and dairy products because their babies are allergic to cow’s milk. On the other hand, of course, for affected children themselves, as soon as complementary foods are introduced.
The focus is on proteins, calcium, B vitamins and iodine:
- Good sources of protein include lean meat, potatoes, legumes, cereal products and eggs (chicken egg white).
- The body obtains B vitamins mainly from animal foods such as meat and fish. However, there are also plant-based suppliers such as grain products.
- Iodine is sufficiently contained in sea fish as well as iodized table salt.
Emergency treatment with medication
Testing whether allergy still exists
A cow’s milk allergy in babies usually subsides over time. For this reason, doctors usually check after some time whether the (extensive) renunciation of cow’s milk and cow’s milk products is still necessary. This is done by means of a provocation test (see below). In the case of a cow’s milk allergy in infants, experts recommend testing at intervals of (six to) twelve months, and in older children at intervals of 12 to 18 months.
What causes a cow’s milk allergy?
A cow’s milk allergy occurs when the immune system sees proteins in cow’s milk as supposedly dangerous and fights them as a result. In total, there are over 20 different proteins in cow’s milk, and each has the potential to cause an allergy. Most sufferers are allergic to caseins and the whey proteins β-lactoglobin and α-lactalbumin.
Often, the symptoms of cow’s milk allergy are IgE-mediated (allergic reactions type I): The immune system specific IgE class antibodies to cow’s milk protein. These cross-link with each other through the cow’s milk proteins and thus trigger the allergic reaction.
Sometimes other allergic reaction types can be observed in cow’s milk allergy such as immune complex mediated reactions (allergic reactions type III).
You can read more about the different allergic reaction types on our allergy overview page in the section Allergy types.
Explanatory approaches for the development of allergies
Experts generally assume that the predisposition to develop an allergy (atopy) is hereditary. If cow’s milk allergies or other allergic or atopic diseases (such as hay fever or neurodermatitis) already occur in the family, a child has a higher probability of also developing an allergy.
In addition, intestinal colonization by bacteria appears to play an important role in the development of allergies. Breastfeeding promotes the colonization of the intestine with helpful lactobacilli and bifidobacteria. Breastfed children suffer less frequently from allergies than others.
Smoking during pregnancy also promotes allergies in children. The same is true if a child is exposed to tobacco smoke after birth.
How is a cow’s milk allergy diagnosed?
Anamnesis
First, the doctor will ask you (as the affected person) or the parents (in the case of affected children) in detail about the history of the disease (anamnesis). Possible questions include:
- When did the symptoms first appear?
- Do you/is your child suffering from diarrhea, nausea, shortness of breath and/or reddening of the skin?
- Are you breastfeeding your child?
- Do you supplement with formula?
- Are there any known allergies in your family?
Tests for cow’s milk allergy
Among other things, it depends on the age of the affected person in which order medical professionals perform the tests and which test reagents they use. For example, in the case of (suspected) food allergy (such as cow’s milk allergy) in a baby, the tests may be performed in a different order and manner than when older children or even adults are the sufferers.
Prick test and IgE determination
In the IgE test, the blood of the affected person is examined for IgE antibodies, which are specifically directed against cow’s milk proteins. You can read about how this works in detail in the article Allergy testing.
The problem with the prick test and the test for IgE antibodies: If no IgE-mediated immediate reactions occur in an affected person, but only other types of allergic reactions (such as type IV reactions), these tests are negative despite the existence of an allergy.
In a diagnostic omission diet (elimination diet), one avoids in a controlled manner for a certain period of time those foods that are suspected of triggering a food allergy – in this case, to anything containing cow’s milk (proteins).
Non-breastfed babies are given an extensively hydrolyzed infant formula or an amino acid formula for the period of the omission diet. This should be selected individually for each child.
What is the course of a cow’s milk allergy?
A cow’s milk allergy can vary in severity. Some sufferers react to the smallest amounts of cow’s milk protein with allergic symptoms, others tolerate the allergen at least in small doses and certain “packaging” (such as cow’s milk in baked form).
The prognosis is generally good. A cow’s milk allergy in a baby usually goes away on its own. But when can an improvement be expected?
Thus, cow’s milk allergy rarely persists beyond childhood into adulthood. It is also rare for it to develop anew in adults.
Can a cow’s milk allergy be prevented?
A cow’s milk allergy is partly genetically determined: The tendency to allergies (atopy) cannot be prevented. However, other factors that can contribute to the development of an allergy can be influenced:
- Women should not smoke during pregnancy and breastfeeding. As a general rule, children should not grow up in a smoking household.
- Infants should be fully breastfed for the first four to six months of life. Mothers should continue to breastfeed as soon as complementary foods are introduced.
- In the first days of life, babies should not be given cow’s milk-based formula.
- A varied diet for the child in the 1st year of life can prevent atopic or allergic diseases. This includes a limited amount of milk and dairy products as part of complementary feeding (up to 200 ml per day).
Read more about these and other tips for the prevention of allergic diseases such as cow’s milk allergy in the article Allergy – Prevention.
