Baby Milk Allergy

Baby Milk Allergy - Rash in Infants

The milk is one of the most common allergens for children under age three. Most infants who are allergic to milk exhibit symptoms early, during their first year, and many outgrow it. A milk allergy is different from lactose intolerance; allergies involve a reaction of the infant’s immune system, while intolerance involves the digestive system. A rash is one possible indication that your infant is allergic to milk.

Many a new mom dealing with a newborn, has suspected that her suffering sweetheart must have a cows’ milk allergy (CMA) or intolerance, especially when well-intentioned friends and relatives are also blaming milk. If you’re breastfeeding, you may assume it’s the dairy in your diet that’s causing your little one to wail; if you’re formula feeding, you assume it’s the cow’s milk in the infant formula that’s causing the trouble.

The problem with these hypotheses: A milk allergy in infants is much less common than most people think (it affects only an estimated 2 to 3 percent of babies), and milk intolerance is even more rare. Confusing the issue further is that many people are unaware of the difference between a milk allergy and milk intolerance. To clear up the confusion, here’s the breakdown on milk allergies and intolerance in breastfed and formula-fed babies.

Milk Allergy Vs. Milk Intolerance

Milk allergy: With a milk allergy in infants, a baby’s immune system reacts negatively to the proteins in cow’s milk. If the baby is breastfed, he’s reacting to the dairy his mother has eaten (the milk proteins pass through breast milk), and if the baby is formula-fed, he’s reacting to the cow’s milk proteins in the formula. In either case, the immune system sees the cow’s milk proteins as foreign substances, and in its efforts to fend off the invaders, the body releases histamine and other chemicals, which cause allergic symptoms in the body. Symptoms of milk allergies in babies include:

  • Frequent spitting up
  • Vomiting
  • Signs of abdominal pain, or colic-like symptoms, such as excessive crying and irritability (especially after feedings)
  • Diarrhea
  • Blood in stool
  • Lack of weight gain
  • Hives
  • A scaly skin rash
  • Coughing or wheezing
  • Watery eyes and stuffy nose
  • Trouble breathing and swelling (especially of mouth and throat), or even anaphylaxis (which is a life-threatening allergic reaction)

Milk intolerance: Milk intolerance, on the other hand, has nothing to do with cow’s milk proteins or the immune system. Instead, it involves the digestive system, and it occurs when a formula-fed or breastfed baby can’t digest the sugar in milk (called lactose). That’s why milk intolerance is also called lactose intolerance. Congenital lactose intolerance (milk intolerance in babies from birth) is an extremely rare metabolic condition. Lactose intolerance more commonly develops in older kids and adults. The few babies with lactose intolerance will usually fare much better on a formula with little or no lactose. Symptoms of lactose intolerance in babies include:

  • Gas
  • Diarrhea
  • Bloated stomach
  • Spitting up
  • Infant eczema
  • Irritability, crying, or other colic symptoms
  • Failure to thrive and gain weight

Types of Milk Allergy Rashes

Many different types of rashes could indicate that your infant is allergic to milk. Any allergic reaction to food can give your infant a rash. Some of the common type of rashes caused by milk allergies are acne, hives and eczema, all of which can appear on any part of your infant’s body. Rashes caused by a milk allergy may also be concentrated around your baby’s mouth. A milk allergy can also create a red ring rash around your infant’s anus, often accompanied by a diaper rash.

Distinguishing Milk Rash from Others

A milk allergy rash usually appears shortly after your infant is exposed to milk, often within a few hours. If your infant is having an allergic reaction, he will often have other symptoms such as diarrhea, vomiting, runny nose, irritability, difficulty breathing and swelling. If your baby is breastfed and allergic to cow dairy in breast milk, he will probably have a reaction within 2 to to 24 hours after the mother is exposed to dairy.


The best way to treat a milk allergy rash is to eliminate the infant’s exposure to dairy. You can do this with an elimination diet, in which you remove all sources of dairy from the baby’s diet. Remove dairy from your infant’s diet for at least two to three weeks, and watch to see if symptoms improve. If you are breastfeeding and suspect that the rash is caused by cow protein in your breastmilk, it may take as long as four weeks for all the dairy to get out of your infant’s system and for symptoms to completely disappear.

Other Common Rashes in Infants

If eliminating all dairy from your infant’s diet does not clear up his rash, then consider other causes for your baby’s rash. Other common types of rash in infants include contact rash, yeast rash and impetigo. If your baby’s rash seems to be an allergic reaction but eliminating milk does not cause it to improve, then consider other possible food allergies as the cause.

Cow’s Milk Allergy (CMA)

Science does not know exactly why some children develop allergies against food, cow’s milk being the most common one in infants and children. Symptoms can be avoided by eliminating cow’s milk protein from your child’s diet.

There are many options for substitutes available, ranging from formulas containing proteins which have been made smaller, to formulas that contain no cow’s milk protein at all, so-called amino acid-based formulas. Luckily, most children outgrow food allergies later in life.

CMA typically develops when cows’ milk is first introduced into your baby’s diet either in formula or when your baby starts eating solids.

More rarely, it can affect babies who are exclusively breastfed because of cows’ milk from the mother’s diet passing to the baby through breast milk.

There are two main types of CMA:

  • Immediate CMA – where symptoms typically begin within minutes of having cows’ milk
  • Delayed CMA – where symptoms typically begin several hours, or even days, after having cows’ milk

Symptoms of cows’ milk allergy

Cows’ milk allergy can cause a wide range of symptoms, including:

  • skin reactions – such as a red itchy rash or swelling of the lips, face and around the eyes
  • digestive problems – such as stomach ache, vomiting, colic, diarrhoea or constipation
  • hayfever-like symptoms – such as a runny or blocked nose
  • eczema that doesn’t improve with treatment

Occasionally CMA can cause severe allergic symptoms that come on suddenly, such as swelling in the mouth or throat, wheezing, cough, shortness of breath, and difficult, noisy breathing.

A severe allergic reaction, or anaphylaxis, is a medical emergency – call 999 or go immediately to your local hospital A&E department.

Treatment for CMA

If your baby is diagnosed with CMA, you’ll be offered advice by your GP or an allergy specialist on how to manage their allergy. You may also be referred to a dietitian.

Treatment involves removing all cows’ milk from your child’s diet for a period of time.

If your baby is formula-fed, your GP can prescribe special infant formula.

Don’t give your child any other type of milk without first getting medical advice.

If your baby is exclusively breastfed, the mother will be advised to avoid all cows’ milk products.

Your child should be assessed every 6 to 12 months to see if they have grown out of their allergy.

How you can help your doctor make a diagnosis

Giving your doctor as much detail about your baby’s symptoms as possible can help speed up the diagnosis process. By keeping a diary of their symptoms, including when they occur and how long they last for, you can help your doctor identify or rule out CMA. Taking photos of any skin reactions, such as a rash, can be helpful too. You should also let your doctor know if there is a history of allergy in your family.

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