Infant colic is the reason for 10% to 20% of paediatrician visits during the early weeks of an infant's life. Colic affects between 5%-40% of infants worldwide. The condition typically presents in the second or third week of life, peaks around 6 weeks, and resolves by the age of 12 weeks in 60% of infants and by 16 weeks of age in 90%.²

Signs and symptoms

Infantile colic is classified as a functional gastrointestinal disorder and occurs equally in breastfed and bottle-fed infants, and in both sexes.³

Signs and symptoms of colic include inconsolable crying, irritability, and screaming without an obvious cause. During these episodes of fussiness, which occur more frequently in the evenings, the infant classically appears red-faced, draws up the legs and tenses up the abdomen. Traditional methods of soothing the infant often fail to relieve the infant's distress.²

The Rome IV criteria describe colic in infants from birth to five months of age to make the definition of infantile colic more consistent for research purposes. The criteria are as follows:²

• An infant who is <5 months of age when the symptoms start and stop
• Recurrent and prolonged periods of infant crying, fussing, or irritability reported by caregivers that occur without obvious cause and cannot be resolved by caregivers
• No evidence of infant failure to thrive, fever, or illness.

Alarm symptoms include fever, poor activity, or a swollen abdomen. Less than 5% of infants with excess crying have an underlying organic disease.³

What causes colic?

The pathophysiology of colic is poorly understood. Possible explanations include aerophagia (swallowed air), over- and under-stimulation, gastrointestinal (GI) discomfort, or intestinal cramping.³

Infants with colic display gut microbiota dysbiosis, barrier alterations, and mild chronic GI inflammation. Faecal samples taken from infants suffering from colic led to visceral hyperalgesia in recipient mice, possibly as a result of microbiota dysbiosis.³

Visceral hypersensitivity could be an important aetiological factor involved in the prototypical colic crying behaviour. Similar perturbations are reported in irritable bowel syndrome. The GI colonisation may develop slower in colicky infants, with a lower diversity and stability.³

The microbiome of colicky infants has low levels of bifidobacteria and lactobacilli, including species with anti-inflammatory effects. There is a decreased number of butyrate-producing species.³

Escherichia coli were reported to be more abundant in the faeces of infants with colic than in those of healthy infants. Proteobacteria, including species producing gas and inflammation, are increased.³

Klebsiella species are detected in larger amounts in colic than in control patients, while enterobacter and pantoea species are present only in the controls.³

The presence of chronic inflammation is illustrated by the fact that faecal calprotectin levels were two-fold higher in infants with colic than in control infants, although older reports contradict this finding and report similar calprotectin levels in infants with and without infantile colic.³

The proven effectiveness of probiotics in treating colic

Numerous studies have proven the effectiveness of colic treatment and prevention via the use of probiotics. Indrio et al (2014) showed that prophylactic use of Lactobacillus reuteri during the first three months, reduced infant crying time (38 vs 71 minutes), the number of regurgitations per day (2.9 vs 4.6), and the mean number of evacuations per day (4.2 vs 3.6) compared to placebo. L. reuteri also reduced the onset of functional gastrointestinal disorders and reduced private and public costs for the management of this condition.⁴

Chau et al (2015) showed that treatment with L. reuteri in breastfed infants with colic resulted in ≥50% crying time reduction compared with infants given placebo.⁵

Bird et al (2017) showed that infants receiving probiotics had a 2.3-fold greater chance of having a 50% or greater decrease in crying/fussing time compared to controls. The team concluded that supplementation with the probiotic L. reuteri in breastfed infants appears to be safe and effective for the management of infantile colic.⁶

REFERENCES

1. Frankel LA, Umemura T, Pfeffer KA, Powell EM, Hughes KR. Maternal Perceptions of Infant Behavior as a Potential Indicator of Parents or Infants in Need of Additional Support and Intervention. Front Public Health, 2021.
2. Banks JB, Rouster AS, Chee J. Colic. [Updated 2022 Aug 1]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. https://www.ncbi.nlm.nih.gov/books/NBK518962/#:~:text=Colic%20is%20estimated%20at%20affecting%2020%25%20of%20infants%20worldwide.,an%20obvious%20cause%20characterize%20colic.
3. Daelemans S, Peeters L, Hauser B, Vandenplas Y. Recent advances in understanding and managing infantile colic. F1000Res, 2018.
4. Indrio F, Di Mauro A, Riezzo G, et al. Prophylactic use of a probiotic in the prevention of colic, regurgitation, and functional constipation: a randomized clinical trial. JAMA Pedia, 2014.
5. Chau K, Lau E, Greenberg S, et al. Probiotics for infantile colic: a randomized, double-blind, placebo-controlled trial investigating Lactobacillus reuteri DSM 17938. J Pedia, 2015.
6. Bird AS, Gregory PJ, Jalloh MA, et al. Probiotics for the treatment of infantile colic: a systematic review. J Pharm Pract