March 2012 Issue

Recognizing Cow’s Milk Protein Allergy in Infants — Evidence Shows Eliminating Milk and Soy Can Help
By Judith C. Thalheimer, RD, LDN
Today’s Dietitian
Vol. 14 No. 3 P. 14

When my son Matthew was born, he was strong and healthy, growing well and meeting every milestone. However, he was terribly fussy. He wouldn’t sleep for more than two hours at a time, and he’d cry inconsolably as if he were in pain. The long walks, endless car rides, and sleepless nights spent cuddling him while pacing the floor didn’t calm him down.

Exhaustion, frustration, and worry gave way to depression and insomnia as I lay awake most nights anticipating that shrieking cry that might come at any moment. The pediatrician couldn’t find any medical reason for his behavior. She sympathetically informed us that our son had infantile colic, and that it would get better with time.

What Is Infantile Colic?
All infants have periods of fussing and crying, but those who cry for three or more hours per day for three or more days per week and for at least three weeks (known as the Rule of Threes) meet the basic definition of infantile colic.1 Typically, colicky behavior begins in the first few weeks of life and resolves spontaneously by age 4 to 6 months. Estimates of the incidence of colic vary widely, but as many as 28% of infants may be affected.2

In 1954, when the Rule of Threes was introduced, colic was thought to be primarily a response to overanxious parenting. Since then, researchers have examined many possible physiological causes that could account for the distress colicky infants exhibit, but no single mechanism has been found. Besides parenting, possible explanations for colic have focused on neurological or gastrointestinal issues.

Anne Eglash, MD, a family physician, clinical professor at the University of Wisconsin School of Medicine and Public Health, and cofounder of the Academy of Breastfeeding Medicine, has treated many colicky infants in her practice and has concluded that they fall into two distinct groups. “Some infants are like Dr Jekyll and Mr Hyde: They have crying episodes around the same time every evening, but they’re happy in between episodes. This type of excessive crying is caused by neurologic immaturity,” Eglash says. “If the baby is fussy all day and night, however, then something else is going on, such as abdominal pain.” My son Matthew fell into the latter group.

Right before his four-week checkup, I noticed a spot of bright-red blood in his diaper. The pediatrician suspected an anal fissure and recommended I soak him in warm baths. In the weeks that followed, the small, bright-red spots or streaks appeared in almost every stool, alone or encased in globs of mucus. While he was still growing well, the fussiness and crying worsened.

Convinced that something was wrong, I took my son to a pediatric gastroenterologist. Based solely on my description of the symptoms of colic accompanied by blood and mucus in his stool, the gastroenterologist made an immediate diagnosis: an intolerance to cow’s milk and soy proteins. To my surprise, Matthew’s fussiness and excessive crying weren’t infantile colic; they were an adverse reaction to food, treatable with nutrition intervention.

Supporting Research
My story is not unique. Cow’s milk proteins are the most common cause of food intolerance in infants, with soy protein ranked second.2 A 1999 study by Tor Lindberg, MD, called “Infantile Colic and Small Intestinal Function: A Nutritional Problem?” reported that approximately 25% of infantile colic is cow’s milk dependent.

Numerous studies have shown that removing cow’s milk proteins from a colicky infant’s diet can cause a significant reduction in symptoms.3 Some of these infants have an immunoglobulin-E (IgE) mediated reaction commonly referred to as cow’s milk protein allergy (CMPA). Others may exhibit similar symptoms caused by non–IgE-mediated, mixed, or cell-mediated reactions. In some studies, these reactions are called CMPA as well, while others use the term cow’s milk protein intolerance (CMPI).

Iacono and colleagues concluded in a 1991 study published in the Journal of Pediatric Gastroenterology and Nutrition that “a considerable percentage of the infants with severe colic also have CMPI and that in these cases, dietetic treatment should be the first therapeutic approach.” Dietetic intervention is also the standard diagnostic procedure: eliminate the suspected allergen from the diet and see if the condition improves. The diagnosis is confirmed if reintroducing the allergen causes the symptoms to return, but this challenge procedure isn’t routine in colicky infants and should be done only under medical supervision at facilities equipped to handle serious allergic reactions.

Treating Formula-Fed Infants
Standard infant formulas are either cow’s milk or soy based. For formula-fed infants, Anthony M. Loizides, MD, an assistant professor of pediatrics at Albert Einstein College of Medicine and an attending physician in the division of pediatric gastroenterology and nutrition at Children’s Hospital at Montefiore, recommends a two-week trial of extensively hydrolyzed formula when CMPA is suspected. “If the infant does not respond,” he says, “it’s unlikely that she or he has CMPA.” If skin rash or gastrointestinal symptoms such as blood in the stools are present, however, a four-week elimination period is recommended. If there’s no improvement on extensively hydrolyzed formula, an amino acid-based formula may be tried. Babies who’ve begun eating solid food shouldn’t be fed foods containing cow’s milk proteins, soy protein, egg, or peanuts.4

Mother’s Role While Breast-Feeding
As in my case, breast-fed infants also may present with excessive crying related to adverse food reactions. Matthew’s condition, known as allergic proctocolitis, is a typical presentation. Milk and soy proteins are the most common culprits, as both have been found in breast milk. The breast-feeding mother must, therefore, exclude all sources of milk and soy proteins from her diet. Eglash also has had success with eliminating corn if the infant doesn’t respond to the removal of milk and soy. Some studies have suggested eliminating other foods known to be highly reactive, such as nuts, wheat, eggs, and fish.

Milk and soy proteins are added to a wide variety of processed foods, but current labeling laws require that manufacturers clearly identify any ingredients that contain protein derived from milk or soybeans as well as eggs, fish, shellfish, peanuts, tree nuts, and wheat. An infant’s condition often improves in as little as 72 hours, but two to four weeks is the recommended trial period. If the elimination diet works, the mother should continue this diet as long as she’s breast-feeding, and, as previously mentioned, any offending food components must be excluded from the infant’s diet when introduced to solid foods.4

Many of the adverse food reactions responsible for excessive crying are temporary, and a challenge should be conducted under medical supervision around the first birthday to determine if the baby is still reactive.

After my son’s diagnosis, I continued to breast-feed, carefully avoiding foods with even trace amounts of milk or soy proteins. My son’s behavior steadily improved as long as I adhered to the diet, and the appearance of blood in his stools gradually lessened. After two months on the elimination diet, all traces of blood in his stool were gone, and my sweet, happy baby was finally sleeping through the night.

— Judith C. Thalheimer, RD, LDN, is a private practitioner based in Pennsylvania.


• “ABM Clinical Protocal #24: Allergic Proctocolitis in the Exclusively Breastfed Infant” by the Academy of Breastfeeding Medicine (

• “About Milk Allergy” by KidsHealth From Nemours (

• GastroKids, children’s digestive health information for kids and parents (


1. Wessel MA, Cobb JC, Jackson EB, Harris GS Jr, Detwiler AC. Paroxysmal fussing in infancy, sometimes called colic. Pediatrics. 1954;14(5):421-435.

2. Nocerino A, Guandalini S. Protein intolerance. Medscape website.

3. Hill DJ, Roy N, Heine RG, et al. Effect of a low-allergen maternal diet on colic among breastfed infants: a randomized, controlled trial. Pediatrics. 2005;116(5):e709-e715.

4. Vandenplas Y, Brueton M, Dupont C, et al. Guidelines for the diagnosis and management of cow’s milk protein allergy in infants. Arch Dis Child. 2007;92(10):902-908.