Signs & symptoms of dairy allergy in babies

Updated April 17, 2017

Cow's milk contains a special protein that can cause an allergic reaction in some infants. Though it is a rare condition, only about 2-3 per cent of infants according to Kids Health, a milk allergy can be a painful condition. Infants can get this milk protein through milk-based infant formulas or via breastmilk after the mother drinks or eats dairy. A parent who thinks her infant may have a milk allergy should ask her doctor to make sure and find an alternative formula. Knowing the signs and symptoms of a milk allergy will help parents to determine if their infant may have this condition.


Infants with a milk allergy may act fussy, or fussier than normal, after drinking milk. This includes infant formula made from milk, and breastfeeding after the mother has drunk milk, according to breastfeeding website Health site Kids Health says this can occur within minutes of drinking the milk or can be delayed for seven to 10 days. The slow reaction is the most common allergic reaction for infants.

Vomiting and Diarrhea

Babies can experience vomiting and/or diarrhoea from a cow milk allergy, says Dr. Paul, assistant professor of Pediatrics, McGill University. Kids Health says there can also be blood in the diarrhoea caused by the milk. Babies may also gag without vomiting as a reaction to the cow milk protein.

Skin Rash

Kids Health says that infants with a milk allergy may also exhibit a skin rash as a reaction to the milk protein. Infants may also have sudden hives or itchy bumps on the skin soon after drinking milk. This rash can be referred to as eczema, says Dr. Paul.

Stomach Pain and Cramping

Though it may be difficult for an infant to express this symptom, Dr. Paul explains that infants may also experience stomach pain and cramping as a symptom of a milk allergy. Parents may see their infant reacting to the pain as colic or irritability, both listed as symptoms from Kids Health.


Very rarely, some infants may suffer a severe reaction called anaphylaxis. According to Dr. Paul, anaphylaxis can cause swelling, difficulty breathing, severe vomiting, and hives. These symptoms begin within minutes of consuming cow's milk. This is the most dangerous allergic reaction and can be fatal if not treated immediately.

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About the Author

Summer Minor is a freelance writer with experience covering many topics. She has been listed as a Top 1000 Writer at Associated Content and has since worked to increase her writing experience.