While unlikely causative, colic could be an early indicator of those at risk and prompt greater focus on early and consistent food allergen introduction.
Infant colic has often been dismissed as a transient or benign condition, but new research suggests it may signal something more significant: an increased risk of developing food allergies in childhood and adolescence.
In a prospective cohort study of 1263 children, researchers found that infants with colic were 70% more likely to develop food allergies in both childhood and adolescence compared to those without.
Importantly, there was no association between food allergy and excessive crying without colic in infancy.
The study, based on participants from the Project Viva cohort in the US, followed children from birth through to mid-adolescence. It recruited mothers in 1999-2002 at their initial obstetrics appointment. Infants were 50% female and 70% white.
Research visits were conducted in infancy (median age 6.3 months), toddlerhood (median age 2.1 years), early childhood (median age 3.1 years), early adolescence (median age 12.9 years) and mid-adolescence (median age 17.5 years), with parents reporting sensitivities to allergens such as egg white, cow’s milk, wheat, sesame, peanut and soy.
Around a quarter of infants were reported to have colic, defined as “unsoothable” crying accompanied by signs of abdominal discomfort, while a further 10% experienced excessive crying without colic.
By early childhood, 13% of children who’d had colic had developed any food allergy, with peanut (5%) and tree nut (4%) being most common, compared to 8% of those without colic or excessive crying, translating to a 70% increased risk (OR 1.70).
Risk of current milk and egg allergies in early childhood were also higher for those who had colic as infants vs those unaffected (OR for milk allergy: 1.8, 95% CI: 0.9, 3.6; OR for egg allergy: 2.0, 95% CI: 0.9, 4.7).
Children with a history of colic had more than double the risk of peanut (OR 2.10) and tree nut allergies (OR 2.60) in early adolescence, with risk persisting into mid-adolescence.
Both colic and excessive crying were associated with higher rates of first-time mothers, preterm birth and maternal atopy. Birthweight for gestational age was highest among unaffected infants and lowest in those with excessive crying.
In a subset of children with blood samples available (n = 242), those who’d had colic had 2.5 times the risk of early childhood IgE sensitisation to peanuts compared with those unaffected (22% vs 11%).
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Sensitisation to cow’s milk was most prevalent in the subset, occurring in 28% of children, followed by egg white (24%) wheat (15%) and peanut (14%). Only 39% of children sensitised to peanut had a parent-reported allergy to it in early childhood.
Taken together, the findings suggested that colic may reflect early immune system differences and underlying gastrointestinal inflammation rather than a behavioural or developmental phase, authors explained.
“Infants with colic may benefit from proven food allergy prevention strategies, including early, consistent introduction of potentially allergenic foods,” they wrote.
“[The findings] suggest that concerns for colic may provide an early opportunity to identify children at high risk of developing atopic conditions and ensure that they benefit from current best practices in prevention strategies.”
They explained that most guidelines recommend peanut introduction between four and six months of age for high-risk infants, identified as those with severe eczema, egg allergy or both.
“However, it is also known that most peanut allergy occurs among children not identified as high risk according to these criteria,” the researchers wrote.
“Our results suggest that infant colic, which commonly manifests in the first few weeks of life and peaks around 6-8 weeks, may provide an additional early marker that could be used for the timely identification of high-risk infants and allow them to benefit from timely peanut introduction.”
Increasingly, colic is being understood as a disorder of gut–brain interaction, with emerging evidence linking it to alterations in the gut microbiome – changes that have also been implicated in the development of food allergies.
The researchers emphasised that colic was unlikely to cause food allergy but may serve as an early indicator of children who are already at higher risk due to underlying biological factors.
The study also highlighted the importance of distinguishing colic from excessive crying. While the two are often used interchangeably, the results reinforce that they are clinically distinct, with only colic showing a clear link to later allergic outcomes.
Rather than viewing colic as a temporary inconvenience, clinicians may need to consider it as a potential early signal of future allergic disease and an opportunity to intervene sooner, the researchers said.
