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How Do I Know if My Baby Has a Cow's Milk Allergy?

How Do I Know if My Baby Has a Cow's Milk Allergy?

Cow’s milk allergy, also known as cow’s milk protein allergy (CMPA), is a common childhood food allergy, and infants who have it may have different experiences after consuming the proteins found in cow's milk.

If you’re ever concerned that your little one may have it, don’t hesitate to contact your pediatrician. They can help you figure out what's going on and support you to ensure your little one stays healthy and happy. Ask your doctor if Enfamil’s Nutramigen hypoallergenic formula may be right for your little one. And be sure to sign up for Enfamil Family Beginnings to receive valuable samples, rebates, and offers on products such as Nutramigen.

Cow’s milk protein allergy indicators

  • Nausea or vomiting
    Your baby could feel sick or might projectile vomit.
  • Reflux
    Most babies experience some degree of reflux (or spit-up), but some babies have more severe reflux problems. They may frequently spit up lots of liquid, forcefully vomit, choke or gag, arch away from the bottle or breast, seem irritable during or after feedings, or have trouble putting on weight.
  • Diarrhea
    Breastfed babies typically have runny, seedy poops. The poop of formula-fed infants tends to be a little thicker. If your baby has diarrhea, you’ll notice frequent watery, foul-smelling loose poops. Babies who have diarrhea may become dehydrated, so you should call your doctor.
  • Unusual poops
    In addition to diarrhea, there could also be blood and/or mucus in your child’s poop. It’s important to speak to your doctor if your baby experiences this issue.
  • Gassiness
    Gas may make a baby's stomach look bloated or feel hard and tense. A baby may pull up their legs or lock them out straight, clench their fists, and pass gas.
  • Constipation
    A baby's poops might look like tiny rabbit pellets or a hard ball. Keep in mind that bowel movement frequency isn't always an indication of constipation. Some healthy infants may go several days without a bowel movement.
  • Hay fever-like indicators
    Cow’s milk allergy can cause sneezing and an itchy, runny, or blocked nose.
  • Breathing difficulties or wheezing
    A chronic cough, persistent runny nose, and raspy, wheezy breathing should be discussed with your baby’s doctor.
  • Anaphylaxis
    Anaphylaxis (anaphylactic shock) is the most serious possible allergic reaction. It comes on quickly, affects the whole body, and is potentially life-threatening. Indications include breathing difficulties, becoming faint, skin irritation, and swelling—especially of the face. Fortunately, this type of allergic reaction is uncommon in infants. If you suspect anaphylaxis, call 911 immediately.
  • Colic
    Excessive crying and fussiness, even though your otherwise healthy baby isn’t hungry, tired, or in need of a diaper change, could be indications of colic due to cow’s milk allergy. Colic tends to follow a pattern of threes: crying for more than three hours per day (usually in the evening), for more than three days per week, and for more than three weeks. Colic often improves by the third or fourth month of age.
  • Itchy rash
    Cow’s milk allergy rash can look like tiny red bumps on your baby's face, scalp, hands, or feet. The bumps may itch, ooze, and crust over or feel like dry, scaly skin.

Cow’s milk allergy vs. dairy sensitivity vs. lactose intolerance

Some cow’s milk allergy indicators, such as gassiness and diarrhea, are similar to dairy sensitivity indicators. However, cow’s milk allergy, dairy sensitivity, and lactose intolerance, are all different. Food allergies involve the immune system, and in the case of a cow's milk allergy, the body's immune system triggers an adverse response to the protein in cow's milk. Lactose intolerance in babies and lactose sensitivity have to do with an inability to fully break down or digest lactose, a milk sugar.

Understanding the steps to a cow’s milk protein allergy identification

If you suspect your baby may have a cow's milk protein allergy, following these steps could make identifying the allergy a bit easier, but remember, any number of things could be causing your baby’s behaviors, so it’s best to consult your pediatrician.

  1. Start keeping a diary of your baby’s issues.
    • Note whether your little one flares up during or after feeds or at certain times of the day.
    • Keep track of indicators over 1–2 weeks.
    • Track which foods your baby is consuming—breast milk, formula, or solids.
    • Note if your baby gets upset when you try to nurse or offer a bottle or whether they seem uninterested in eating even when you know they’re hungry. Bring your diary to your pediatrician appointment to discuss your concerns together. Download our feeding log to record your baby’s eating and stooling behaviors.
  2. Prepare questions for your pediatrician. There are no wrong questions, but download our list of questions to ask your pediatrician to get you started on the right track to a productive conversation.
  3. Test and learn. To confirm if your little one has a cow’s milk allergy, your doctor may suggest an elimination diet and food challenge guided by them or another health care professional, such as a dietitian. A skin prick or blood test may also be recommended to gather more data about the body’s immune responses. Do not perform a food challenge on your own–be sure to consult with your doctor first.
  4. Your doctor may suggest specific dietary changes. If you’re breastfeeding, ask your doctor if you should take cow’s milk out of your diet. If you’re formula-feeding, you may be advised on suitable hypoallergenic formulas such as Nutramigen.
  5. If your baby continues to have issues, your pediatrician may refer you to a specialist who can advise you on further next steps or look into other food allergies.

Always speak to a doctor if you’re ever worried about your baby’s health. Get immediate medical help if your baby has trouble breathing, seems faint, or has swelling around their mouth and face.


Cow’s milk allergy management

If your doctor suspects cow's milk allergy, they may suggest eliminating cow's milk proteins from your baby’s diet. This isn't as daunting as it might sound.

  • For breastfed babies
    Cow's milk protein fragments can be passed in breast milk when the mom consumes dairy products. Breast milk still provides the best nutrition for your baby, so you shouldn't stop nursing. You should not remove dairy foods from your diet without speaking to your doctor.
  • For formula-fed babies
    Switching to a hypoallergenic formula (meaning it has been specially designed for babies with cow's milk allergy) may help. Most babies with cow's milk allergy feel better after switching to an extensively hydrolyzed, hypoallergenic formula like Nutramigen. In fact, some cow’s milk allergy indicators like colic may stop within 48 hours1 after a formula change. Talk to your doctor to see if this is the option for you.

As your baby gets older, your doctor may suggest you start reintroducing your child to foods made with cow's milk. This should always be done carefully and under a doctor's supervision. Most children outgrow cow's milk allergy eventually,2 so you may not be facing a lifetime of saying no to your child's pleas for ice cream and mac and cheese. In the meantime, there are other ways you can manage CMA and the indicators associated with it.

Ask your doctor about Nutramigen®

If you think your little one may have an allergy to cow’s milk protein, talk to your doctor about switching to Nutramigen®, a hypoallergenic formula that is clinically shown to manage colic due to cow's milk allergy in as quickly as 48 hours.3 It helps more babies overcome cow’s milk allergy and return to consuming regular milk in as soon as six months of feeding.4 It’s also lactose-free, which helps reduce the incidence of future allergies related to cow’s milk.* And no matter what type of Enfamil formula you choose, you can start receiving up to $400 in savings, exclusive rewards, and support by joining Enfamil Family Beginnings. Enjoy a variety of benefits, including discount checks and digital rebates on Enfamil products. You may also be eligible for free samples.


*Asthma, eczema, rhinoconjunctivitis, and urticaria at 3 years compared to Nutramigen without LGG. Feeding began at 4 months of age or older in the study (ref#5).


1Studied before the addition of LGG®, DHA, and ARA.


3Lothe L, Lindberg T. Cow’s milk whey protein elicits symptoms of infantile colic in colicky formula-fed infants: a double-blind crossover study. Pediatrics. 1989; 83: 262-266.

4Berni Canani R, Nocerino R, Terrin G, et al. Effect of Lactobacillus GG on tolerance acquisition in infants with cow’s milk allergy: a randomized trial. J Allergy Clin Immunol. 2012;129:580-

5Nocerino R, Bedogni G, Carucci L, Cosenza L, Cozzolino T, Paparo L, Palazzo S, Riva L, Verduci E, Berni Canani R. The Impact of Formula Choice for the Management of Pediatric Cow's Milk Allergy on the Occurrence of Other Allergic Manifestations: The Atopic March Cohort Study. J Pediatr. 2021 May;232:183-191.e3

All information on Enfamil, including but not limited to information about health, medical conditions, and nutrition, is intended for your general knowledge and is not a substitute for a healthcare professional's medical identification, advice, or management for specific medical conditions. You should seek medical care and consult your doctor or pediatrician for any specific health or nutrition issues. Never disregard professional medical advice or delay seeking medical treatment, care, or help because of information you have read on Enfamil.