Infantile colic affects up to 40% of infants worldwide.[1] Colic now has various definitions, but the original criteria, described by Morris Wessel in 1954, are described as the “rule of 3s”: crying for more than 3 hours per day, for more than 3 days per week, lasting at least 3 weeks in an otherwise healthy infant.[2] Peak symptoms occur around 6 weeks of age, and resolution of symptoms is typically seen by 3-6 months of age.[3]

Colic episodes are usually characterized by abrupt onset and conclusion of intense and inconsolable crying. For unknown reasons, episodes are more common in the evening. The unprovoked and distressing nature of these episodes can lead to significant parental frustration and multiple medical visits.

The cry of colic is louder and of higher pitch than typical crying. Associated symptoms are related to hypertonia and include flushing, circumoral pallor, tense or distended abdomen, drawing up of the legs, clenching of the fingers, or arching of the back.

Nutritional contributors are described in Nutritional Considerations (see below).

Risk Factors

Risk factors for infantile colic are poorly understood. The condition does not appear to be related to gender, gestational age at birth, season of the year, or type of feeding (breast versus bottle).[3] The following list identifies possible risk factors that have emerged in research studies, but whose validity has yet to be established:

Perinatal exposure to tobacco or nicotine.

Parental variables, including both maternal and paternal mood disorders, and family stress. Parental behaviors in response to crying may also contribute.

Certain feeding behaviors, including swallowing of air, excessive feeding, and underfeeding.

Pathophysiology

The biological mechanisms underlying colic are also poorly understood. Possible triggers include alterations in fecal microflora and maternal smoking or nicotine replacement therapy. The mechanisms of action are gastrointestinal immaturity or inflammation, intolerance to cow’s milk protein or lactose, increased serotonin secretion, and poor feeding technique.[4],[5],[6],[7]

Diagnosis

The differential diagnosis of a crying infant is broad. Colic is a diagnosis of exclusion. A detailed history and physical are essential to rule out serious conditions. Red-flag symptoms that require immediate and thorough evaluation include fever, distended abdomen, and lethargy.

After serious diagnoses have been excluded, questions regarding social factors and how parents respond to their crying baby are important to ask. It is essential to consider the possibility of parental abuse of the infant.

In addition to Wessel’s “rule of 3s” discussed above, the Rome III clinical diagnostic criteria for functional gastrointestinal disorders are used to characterize colic.[8]

If malabsorption, inadequate feeding, pyloric stenosis, intussusception, bowel obstruction, or gastroesophageal reflux are possible, consider laboratory testing, stool samples, and imaging, as appropriate.

Treatment

Colic is self-limiting and will resolve with time. Offering reassurance to the family is helpful, and all interventions should be individualized to the family’s needs. In addition to dietary factors described below, the following interventions may help decrease the severity and length of symptoms.

Although changes in feeding techniques do not always resolve the problem, these interventions are of little risk and are often cost-free. In bottle-fed infants, reducing air swallowing by feeding in a vertical position (using a curved bottle) in combination with frequent burping may be beneficial. Using a bottle with a collapsible bag also may help. Changes in breastfeeding technique may be warranted but should be individualized.

Reduction of stimulation may be helpful. Neurobehavioral assessments have shown that infants with the greatest responsiveness to external stimuli are more likely to be colicky compared with other infants.[9] This may explain the finding of a systematic review that stimulation reduction was a beneficial strategy for colicky infants.[10] Conversely, evidence suggests that soothing techniques, including various types of stimulation, may also be successful in reducing symptoms. Some of these techniques include holding, walking, rocking, using an infant swing, providing a warm bath, and rubbing the infant’s abdomen.[11] Swaddling, white noise, and gentle rocking motion can sometimes be helpful.

Simethicone and proton pump inhibitors have not generally been shown to be helpful. Dicyclomine and other antispasmodics should not be used to treat infantile colic due to lack of proven efficacy and risk of serious adverse effects, including seizures and death.

Trials of acupuncture and infant massage have had conflicting results, and further studies are needed to determine their benefits and harms.[12],[13]

Administration of sucrose solution, herbal tea, and switching from standard formula to hydrolyzed formula have all been shown to reduce hours per day of crying, though hydrolyzed formula seems to have the greatest impact.[14]

It is important to remember that colic can be frustrating for parents. It may be helpful to caution overtired and frustrated parents to never shake the baby and to have a family member or friend look after the baby when parents need a mental health break.[15]

Nutritional Considerations

Research on the links between diet and infantile colic has been limited. Nevertheless, evidence indicates that elimination of cow’s milk products or certain other food products from a breastfeeding mother’s diet or replacement of cow’s milk and cow’s milk-based formula with hypoallergenic or hydrolyzed formula may be helpful in some cases.

A 2-week trial of a different formula may be considered for infants with colic. To make the change more palatable, parents can transition to hydrolyzed formula by mixing the new formula with regular formula incrementally over 4 days, until only hydrolyzed formula is being given. These formulas are expensive, however, and may not be covered by assistance programs (e.g., Special Supplemental Nutrition Program for Women, Infants, and Children). If the new formula is successful in reducing colic symptoms, regular formula may be restarted after 3-6 months of age.[3]

Several lines of evidence support the possibility that cow’s milk proteins may elicit colic symptoms. The first is the observation that colic symptoms often improve in infants who are either given formula free of cow’s milk proteins or breastfed by mothers who avoid cow’s milk.[16],[17] In addition, many infants experience colic symptoms after ingestion of breast milk subsequent to maternal ingestion of whey capsules.[17]

Despite the belief that the maternal intestinal wall provides a barrier to large molecules, it has been shown that cow’s milk (and other) proteins are absorbed from the maternal gastrointestinal tract into the circulation and subsequently pass into breast milk. Passing on these proteins when breastfeeding is a suspected cause of colic.[18] The solution is for the breastfeeding mother to avoid dairy products.

Recent evidence suggests that colic in breastfed infants may be improved with the probiotic Lactobacillus reuteri DSM 17938.[19],[20] Formula-fed infants, however, appear to have increased symptoms with this therapy.[5] Formula-fed infants may, on the other hand, benefit from partially, extensively, or completely hydrolyzed for¬mulas. A large review article found a significant decrease in crying time in formula-fed infants who switched to these types of feedings.[21] Additionally, although lactose intolerance is not thought to be a cause of colic, treatment of lactose-containing formula with lactase may decrease symptoms.[22]

Evidence on the use of soy formulas for the treatment of colic is limited. A meta-analysis including 4 small trials using soy formula found some symptom reduction after transitioning participating infants to a soy-based formula. Soy can also be an allergen, however, and may cause allergic symptoms in susceptible infants.

Breastfeeding mothers may try a low-allergen diet, as significant reductions in colic symptoms have been observed in mothers who eliminated cow’s milk, eggs, peanuts, tree nuts, wheat, soy, and fish from their diet.[23]

Rarely, patients with colic may have isolated fructose malabsorption.[24] A study of colicky infants found carbohydrate malabsorption revealed by increased breath hydrogen excretion.[25] Excluding sweetened juices and other fructose-containing products may reduce colic symptoms in these infants.[24]

Orders

For breastfeeding mothers, see Basic Diet Orders chapter.

Parental smoking cessation.

Nutrition consultation to advise breastfeeding mothers on the use of a dairy-free or hypoallergenic diet, as appropriate, and arrange follow-up.

Social work consultation to assess the home environment and arrange follow-up to evaluate the possibility of ill feelings toward the infant, care provider burnout, and maternal depression or anxiety

What to Tell the Family

In the absence of other medical issues, colic is always self-limited and typically resolves by 6 months. Reassurance of the family is important. Dietary changes, including a dairy-free or hypoallergenic diet for breastfeeding mothers or the use of a hydrolyzed formula, may be given a therapeutic trial. A trial of soy formula may be an appropriate option, as well. If doing so, it is important to use soy infant formula and not common soy milk.

All household smokers should stop smoking for the present and future health of the baby and other family members.

Caregivers should understand that they may not be able to console the infant on every occasion, and that caring for a colicky baby is very stressful. They should be encouraged to ask for help if anxiety, depression, or feelings of frustration or anger toward the baby arise.

References