All newborn babies cry sometimes, with up to 2 hours of crying a day being considered normal. Excessive crying or fussiness, however, can be extremely stressful and worrying for parents. This feature looks at the difference between colic and cow’s milk allergy as a cause of fussiness in babies.

Colic

The term “colic” is used by doctors and parents to refer to long crying or unsettled periods for no apparent reason in the first few months of life. The “rule of three” is the most widely used definition of colic.  This means crying that lasts for more than 3 hours a day, more than 3 days per week, and persisting for longer than 3 weeks may be considered as not normal and may be due to colic.  The crying episodes in colic usually start suddenly and concentrate during the evening. The cry is louder and more high-pitched than normal with a “piercing” or “grating” quality. Classically the colicky baby is growing well and has normal stools. Symptoms get better (often quite suddenly) in 60% of 3 month olds and 90% of 4 month olds. There are no known detrimental long-term effects of colic.

Colic is common and occurs in up to 40% of babies. It occurs equally among males and females, firstborns and subsequent children, breastfed and formula fed babies, term and preterm babies; and there is no good evidence for an increase after caesarean section. It can run in families.

The exact cause of colic is unclear. Colic may well be caused by many factors, including “immaturity” of the gut, trapped wind, feeding difficulties (e.g. overfeeding, underfeeding, swallowed air), hypersensitivity to environmental stimuli, emotional stress in the family or just the infant’s temperament. Medical causes such as cow’s milk allergy, reflux or lactose intolerance may play a role in a small subset of patients.

Management of colic is based on supporting the family and baby through the first few difficult months, through soothing activities (baby massage, gentle swaddling, motion, white noise, upright carrying in a baby carrier), and feeding advice (ensuring a good latch, correct amount of feeds, winding strategies). Most children will not need any further tests to be done and parents can be reassured, unless there are other concerning features or growth issues.

Medications should be used sparingly in colic. The lactase enzyme which helps break down lactose (the sugar in cow’s and human milk) is available, but clinical studies have shown conflicting results. Simethicone “wind” drops in theory help the baby pass winds more easily but do not have a proven track record in colic. Antispasmodics, popular “colic mixtures” and homeopathic medications should be used sparingly as they may cause side effects.

Cow’s Milk Protein Allergy

Cow’s milk protein allergy may contribute towards colic in a small subset of patients. The prevalence is 2-3%, far lower than the prevalence of colic. A family history of allergic diseases increases the risk. Cow’s milk allergy is an abnormal response to the protein in cow’s milk, which, unlike lactose intolerance, is caused by the immune system. Symptoms of milk allergy can occur soon after drinking the milk with hives, swelling and even chest or circulatory signs (Immediate or IgE type allergy); or be delayed by several hours to days after consuming cow’s milk protein, causing gut or skin symptoms (delayed type / non IgE mediated food allergy). The delayed type of cow’s milk allergy may mimic colic with fussiness and digestive gripes. However, certain features make cow’s milk allergy more likely than pure colic. These include blood in the stools, diarrhoea or constipation, poor growth, excessive vomiting, associated eczema or wheezing. Patients with cow’s milk allergy respond within a week or two to removal of cow’s milk (and all cow’s milk cheese, yoghurt etc) from their diet; either by the mother avoiding cow’s milk in breast feeding babies, or by changing to a cow’s milk-free formula milk. When cow’s milk is reintroduced symptoms come back. Generally, if there is no response within 2 weeks of removing cow’s milk from a young baby’s diet, then cow’s milk allergy is unlikely.

Cow’s milk allergy gets better in the vast majority of patients, often by 2-3 years of age, but even later in some children. Cow’s milk allergy takes much longer to resolve than infantile colic.

Cow’s milk allergy differs from lactose intolerance.  Lactose intolerance is a difficulty in digesting lactose, which is the sugar component of cow’s milk. Lactose intolerance may lead to severe cramps and diarrhoea shortly after consuming cow’s milk or dairy, but generally not to vomiting or blood in the stools, and not to “systemic” features such as eczema or chestiness. In the majority of early-onset cases, lactose intolerance resolves within a few months.

Bottom Line: Colic is common and usually resolves by 3-4 months of age, as the gut and neurological systems in a baby mature. There is no cure for colic but some strategies may bring relief. Cow’s milk allergy is much less common and can mimic colic. However, usually there are additional symptoms (colic “PLUS” other symptoms) such as failure to thrive, prolonged symptoms, blood in the stools, eczema or vomiting with a definite response to withdrawing cow’s milk from the infants diet. Cow’s milk allergy generally takes 2-3 years to resolve, even longer in some children.