Cow’s milk protein allergy: a parent's guide

Cow’s milk protein allergy (CMPA) is a condition that affects babies and infants as a result of an adverse reaction to the proteins found in cow’s milk. This can be concerning for parents, causing them to worry about their child’s symptoms, nutritional requirements and growth. Distinguished consultant general paediatrician Dr Marie White provides a guide for parents.

What is cow’s milk protein allergy?

Cow’s milk protein allergy (CMPA) is a reaction to the proteins found in cow’s milk, predominantly  casein and whey. When a child with cow’s milk protein allergy (CMPA) consumes cow’s milk or products containing cow’s milk, their immune system mistakenly identifies these proteins as harmful and mounts an immune response.

Symptoms of cow’s milk protein allergy

The symptoms of CMPA can vary widely from person to person and depend on whether the reaction is immediate (IgE-mediated) or delayed (non IgE-mediated).

In immediate (IgE-mediated) CMPA the immune system releases IgE antibodies triggering a cascade of events that lead to the release of various chemicals including histamine. These symptoms are usually immediate or within 2 hours of ingesting the cow’s milk and include:

• hives, swelling, wheezing and in severe cases, anaphylaxis, which is a life-threatening allergic reaction requiring immediate medical attention.

Delayed (non IgE-mediated) CMPA is a delayed more complex reaction occurring 2-24 hours after ingestion of cow’s milk and does not involve IgE antibodies. Other parts of the immune system are activated including the digestive system, leading to a range of symptoms including:

• constipation, diarrhoea, eczema, reflux, vomiting or blood in stools.

Diagnosis of cow’s milk protein allergy

If you suspect that your child has CMPA, it is helpful to consult a paediatric specialist for an accurate diagnosis. Diagnosis typically involves a combination of medical history, physical examination, and a trial of dairy exclusion. For IgE-mediated CMPA, children may need to be referred for skin prick tests or blood tests to detect specific IgE antibodies to cow’s milk proteins.

Management and treatment of cow’s milk protein allergy

The primary treatment for CMPA involves the elimination of cow’s milk and all products containing cow’s milk proteins from the diet. In infants who are breastfed, the mother may need to modify her diet to exclude cow’s milk. For formula-fed infants, specialised hypoallergenic formulas are available.

Outgrowing cow’s milk protein allergy

Many children with CMPA will outgrow their allergy, although the timing of this can vary. Regular follow-up with a paediatrician is helpful to monitor the progression of the allergy and determine when it may be safe to reintroduce cow’s milk into the diet.

If your child is showing signs of cow’s milk protein allergy and would like to book a consultation with Dr White, do not hesitate to do so by visiting her Top Doctors profile today