Allergic Colitis During Breastfeeding

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Babies who are 100% breastfed and have bloody stools may be allergic to milk. This does not mean that they're allergic to breastmilk, but rather that they are usually allergic to the cow's milk proteins that are present in the milk that their mother drinks and are subsequently are passed into her breast milk.

These cow's milk proteins trigger allergic colitis, which is the name for this condition in which infants have bloody stools. Colitis also can be triggered in infants when they are exposed (either in breast milk or formula) to proteins found in soy or goat's milk.

Baby Formula and Allergic Colitis

Babies fed formula can also have allergic colitis because many forms of infant formula are based on cow's milk. A switch to a more hypo-allergenic formula, like Nutramigen Lipil or Alimentum, usually helps these babies. Because soy formula can also cause allergic colitis, a soy protein-based formula is not typically a good substitute.

How long should babies stay on their new formula? Although some experts recommend continuing the hypo-allergenic formula until 12 months, at which time you might slowly introduce cow's milk, others might introduce a cow's milk-based formula even earlier, after the infant has been on the hypo-allergenic formula for at least six months.

For babies who can't tolerate Nutramigen or Alimentum, formulas made up of 100% free amino acids are also available, including Neocate, PurAmino, and EleCare.

Allergic Colitis in Infants

Most food allergies are triggered by antibodies and cause immediate symptoms, like ​hives and difficulty breathing. In contrast, allergic colitis is a delayed-type hypersensitivity reaction and occurs when milk proteins induce an inflammatory response in the intestine. Signs and symptoms of allergic colitis often begin when infants between the ages of two weeks and six months and might include:

  • Bloody stools
  • Diarrhea
  • Excessive gassiness
  • Some fussiness

The treatment is simply to remove whatever is triggering your child’s symptoms, which is usually cow’s milk proteins. After about three to four days, you should then see the symptoms gradually get better.

Seek immediate medical attention if your child has more severe symptoms associated with bloody stools, including excessive fussiness, persistent vomiting, or fever.

Breastfeeding and Allergic Colitis

While babies with known or suspected allergic colitis receiving formula should switch to a more hypoallergenic formula, breastfed babies should continue breastfeeding, with the only "prescription" being that their mother should avoid all milk and dairy products. And these mothers should talk to their doctor about alternative sources of calcium since drinking cow’s milk and soy milk is a common way for many people to get calcium in their diet.

Other foods can also trigger allergic colitis, and many foods can have 'hidden ingredients' to which you might be allergic, so learn to read food labels and get extra help if this problem continues, especially if you are considering stopping breastfeeding. In addition to milk and soy, other foods to eliminate might include chocolate, citrus fruits, corn, eggs, nuts, peanuts, strawberries, and wheat.

A pediatric gastroenterologist can help if your child with allergic colitis has severe symptoms, including weight loss, or if you are having trouble finding an elimination diet that works. A very low-allergen elimination diet might be tried if nothing else is working and this would include only eating foods like chicken or lamb, pears, squash, and rice while breastfeeding, in addition to taking a multivitamin and mineral supplement.

Because this is a restrictive diet, a nutrition professional should be consulted to make sure you and your baby get adequate nutrition.

Fortunately, allergic colitis is often temporary, with symptoms disappearing (when challenged) by the time your baby is about a year old. But the cow's milk hypersensitivity may not really be gone.

Having bloody stools also can be caused by intestinal infections or from rectal tears, a common complication of being constipated. That makes it important to talk to your pediatrician if you think that your baby has allergic colitis.

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  1. Sierra salinas C, Blasco alonso J, Olivares sánchez L, Barco gálvez A, Del río mapelli L. Allergic colitis in exclusively breast-fed infants. An Pediatr (Barc). 2006;64(2):158-61. doi:10.1157/13084176

  2. Lozinsky AC, Morais MB. Eosinophilic colitis in infants. J Pediatr (Rio J). 2014;90(1):16-21. doi:10.1016/j.jped.2013.03.024

Additional Reading
  • Academy of Breastfeeding Medicine. ABM clinical protocol #24: allergic proctocolitis in the exclusively breastfed infant. Breastfeed Med. 2011 Dec;6(6):435-40.
  • American Academy of Pediatrics. Use of Soy Protein-Based Formulas in Infant Feeding. Pediatrics Vol. 121 No. 5 May 1, 2008. pp. 1062 -1068
  • Geaney, Casey, MD. Prevalence and Outcome of Allergic Colitis in Healthy Infants With Rectal Bleeding: A Prospective Cohort Study. Pediatrics Vol. 118 No. Supplement 1 August 1, 2006. pp. S13
  • Yu, Man-Chun. Allergic Colitis in Infants Related to Cow’s Milk: Clinical Characteristics, Pathologic Changes, and Immunologic Findings. Pediatrics & Neonatology. Volume 54, Issue 1. February, 2013.