EVIDENCE-BASED ANSWER
Infantile colic, defined as excessive crying in an otherwise healthy baby, is a distressing phenomenon, but there is little evidence to support the many treatments offered. Several small studies report some benefit from use of a hypoallergenic (protein hydrolysate) formula, maternal diet adjustment (focusing on a low-allergen diet), and reduced stimulation of the infant. While dicyclomine has been shown to be effective for colic, there are significant concerns about its safety, and the manufacturer has contraindicated its use in this population. An herbal tea containing chamomile, vervain, licorice, fennel, and balm-mint was also effective in a small RCT, but the volume necessary for treatment limits its usefulness (strength of recommendation: B, inconsistent or limited-quality patientoriented evidence). The one proven treatment is time, as this behavior tends to dissipate by 6 months of age.
CLINICAL COMMENTARY
For pure colic, only time will help
Anne Eglash, MD
Department of Family Medicine, University of Wisconsin Medical School, Madison
A broad definition for colic may capture infants who cry for a variety of reasons. I consider pure colic to be a patterned daily behavior of crying that a parent can predict will occur and stop at certain times, and the baby is fine at other times of day. For these babies, I wouldn’t expect a change in formula or maternal diet to help; they greatly improve by about age 3 months.
However, for babies who are fussy and difficult to console throughout day and night, further evaluation and dietary changes are worth trying. For breastfeeding mothers, I usually start with dairy avoidance and test the baby’s stools for microscopic blood to be sure there is no colitis related to maternal diet. Only if there is evidence of infant colitis or allergy should a more restrictive maternal diet be prescribed. For formula-fed infants, a change to a proteinhydrolysate formula is worth a try, the main risk being the cost of the formula.
Evidence summary
Colic has been described using the “rule of 3”: crying for at least 3 hours per day on at least 3 days per week for at least 3 weeks.1 The distinction can be subtle; a normal infant can cry more than 2 hours per day. This syndrome has its onset typically in the first few weeks of life. It spontaneously resolves by age 4 to 6 months. Prevalence depends on the definition used for colic; approximately 5% to 25% of infants meet some reasonable definition of colic.2 The cause of infantile colic is poorly understood. Although clinicians tend to focus on a likely gastrointestinal cause, neuropsychological issues, food allergy, and parenting misadventures are also potential contributing factors.
There are myriad strategies—ranging from craniosacral osteopathic manipulation to car ride simulation—offered for dealing with infantile colic. Although none of these treatments has been validated in rigorous studies, the available evidence offers tentative support for 3 strategies: (1) a trial of a hypoallergenic (protein hydrolysate) formula (for formula fed infants), (2) a low-allergen maternal diet (for breastfeeding mothers), and (3) reduced stimulation of the infant.
A systematic review analyzed controlled clinical trials lasting at least 3 days involving infants less than 6 months of age who cried excessively.3 Twenty-seven studies were included; the outcome measure was colic symptoms, typically reported as duration of crying. Two reports studying hypoallergenic (protein hydrolysate) formula in nearly 130 infants found an effect size of 0.22 (95% confidence interval [CI], 0.10–0.34) for the hypoallergenic formula. Additionally, 3 behavioral trials (involving nearly 200 infants) revealed the benefits of reduced stimulation of the colicky infant (effect size of 0.48; 95% CI, 0.23–0.74).
A more recent systematic review4 followed a similar high-quality search strategy and identified 22 articles, and reported a number needed to treat (NNT) of 6 for the 2 hypoallergenic formula studies identified in the previous review.4 Because of concern regarding the quality of the behavioral studies involving infants with colic, the authors of this second review only included 1 small (42 patients) trial of decreased stimulation, which resulted in a relative risk (RR) of 1.87 (95% CI, 1.04–3.34) and a NNT of 2. There was some inconclusive evidence to suggest benefit to dietary adjustment for breastfeeding mothers (specifically, the avoidance of cow’s milk and other potential allergens like nuts, eggs, and wheat).