In cow's milk allergy (CMA) the  immune system mistakenly identifies a  protein in cow's milk as harmful and triggers an  allergic reaction. This leads to a range of symptoms that can vary in type, severity and time of onset from baby to baby.

The symptoms of CMA and the severity of the reactions are wide ranging. They can include colic, skin reactions (such as a red itchy rash, eczema or swelling of the lips, face and around the eyes), digestive problems (such as vomiting, abdominal pain or diarrhoea) and hay fever-like symptoms (such as sneezing or itchy, blocked or runny nose). Symptoms can range from mild to severe reactions.

These symptoms can either appear immediately after consuming dairy (within minutes or up to two hours) or may be delayed, taking a few hours or up to a few days to develop. Babies with CMA may have a mixture of both 'immediate' (usually  IgE-mediated) and 'delayed' (usually non-IgE-mediated) symptoms. Symptoms may also lead to night-time waking, crying or distress during feeding, or poor weight gain. Find out more about the different types of cow’s milk allergy.

A complex group of organs and cells that defends the body against bacteria, viruses and substances that are perceived as harmful.
A nutrient composed of one or more long chain of amino acids. Proteins are an essential part of all living organisms, especially as structural components of body tissues, as enzymes and as antibodies.
Occurs when the body’s immune system overreacts to a harmless substance known as an allergen. Babies with cow’s milk allergy have allergic reactions to cow’s milk protein, such as colic (due to cow’s milk allergy), hives, skin rashes and respiratory and digestive problems.
Immunoglobulin E. A class of antibodies produced by the immune system that triggers many of the signs of allergic reactions. IgE antibody levels are often high in children with an allergy.

Immediate symptoms

(usually IgE-mediated)

Can appear within minutes or up to two hours after eating a food containing cow’s milk protein and may include:

Swollen lips, tongue or face


Hives, rash, redness, itching or swelling

(Raised, red and often itchy bumps on the skin that could stay in one area or spread. Swelling under the skin)


Eczema flare up

(Sudden triggering of red, itchy, and cracked skin)


Hay fever-like symptoms

(Sneezing or an itchy, runny or blocked nose. Eye inflammation)



(Frequent, loose and watery poos)


Tummy pain



(Being sick)


Breathing difficulties

(Coughing, chest tightness, wheezing or shortness of breath)


Anaphylaxis seek emergency help immediately

(Includes sudden and severe breathing problems, fast heartbeat and itchy raised rash)

Delayed symptoms

(usually non-IgE-mediated)

Can appear within a few hours or up to a few days after eating a food containing cow’s milk protein and may include:


Colic-type symptoms

(Excessive and frequent crying)



(Spitting up during or after feeds)


Eczema, itching or redness

(Red, itchy, or cracked skin)


Tummy pain

(Painful wind)


Food refusal



(Less frequent poos and discomfort when trying to poo)


Unusual stools

(Frequent or loose poos or poos that contains blood or mucus)






A digestive problem that causes complications because of digested food flowing back into the oesophagus. Babies who have reflux may frequently spit up lots of liquid, arch away from the bottle or breast, or seem irritable during or after feedings.
Anaphylaxis, or anaphylactic shock, is a severe symptom of an allergy and can be life threatening. Anaphylaxis usually occurs suddenly after exposure to the allergen and quickly gets worse. Symptoms include: Swelling of the tongue or throat, difficulty in swallowing or speaking, wheezing, persistent cough or severe asthma, dizziness, collapse of loss of consciousness (floppiness in babies), fast heartbeat, clammy skin, itchy, raised rash, feeling or being sick, stomach pain.

Please be aware that this is not an exhaustive list of CMA symptoms. Some of these symptoms can also occur for reasons other than CMA, so it is important to discuss them fully with your doctor.


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