Infantile colic is now commonly defined as distress or crying in an infant, which lasts for more than three hours a day, for more than three days a week for at least three weeks in an otherwise healthy infant. It is a common condition and, despite much research on the subject, the underlying cause is still the subject of debate.¹ There is some evidence that the condition is linked to high levels of motilin and ghrelin, hormones secreted by cells in the small intestine which have an effect on intestinal motility.²

Other theories include food allergy, disturbed gut motility and visceral hypersensitivity.³

Epidemiology

Infantile colic is very common in occurring but the precise incidence is unknown as many parents do not seek professional help. Others may seek professional help for what may be considered as normal levels of crying.^4,5 One population-based study found the incidence of infantile colic to be 3.3-17%, depending on the definition used and whether the symptoms were reported prospectively or retrospectively.⁶

One study suggested that maternal smoking and passive infant smoking at the age of five weeks were risk factors. Breast-feeding tended to ameliorate these effects.⁷

Presentation

Symptoms

The symptoms seen in infants described as having colic are all non-specific and infantile colic must be a diagnosis of exclusion when the clinician is satisfied that the child is otherwise healthy. Commonly described features of colic include:⁸

• Inconsolable crying - typically high-pitched and occurring frequently in the afternoon or evening
• Redness of the face
• Drawing up of knees
• Flatus

A history should include:

• Feeding - breast/bottle
• Weight gain
• Bowel habit- stool consistency/colour/blood
• Vomiting or reflux
• Timing of crying
• Duration of crying

An examination should include:

• General examination - size of infant/hydration/apparent injury
• Abdominal examination including hernial orifices and genitalia

Differential diagnosis

Inconsolable crying and distress may indicate pain or other physical discomfort and other possible causes of pain should be sought in an acute situation, although many parents will present with a history of inconsolable crying and an infant who appears to be thriving and content.

In an acute situation when faced with a distressed infant consider:

• Physical discomfort - cold, wet, hungry
• Severe nappy rash
• Corneal abrasion from infant's nails
• Intussusception
• Volvulus
• Strangulated hernia
• Torsion of the testis
• Non-accidental injury

When the history is over a longer period of time consider:

• Reflux oesophagitis
• Lactose intolerance
• Parenting skills and experience of parents
• Maternal post-natal depression

Investigations

The diagnosis is usually made using history and examination alone and does not normally require any further investigations. Infants who exhibit atypical features, or in whom the diagnosis is in doubt, should be referred for a specialist opinion either as an emergency or to an out-patient clinic depending on the clinical presentation.

Associated diseases

Infantile colic may be associated with cow's milk intolerance in some cases.

Management

Non-drug⁹

• The parents of infants with colic may require support as they will be anxious as to the cause of the crying and their apparent inability to help the child. General advice to the parents may be all that is needed in terms of feeding regimes, temperature of the child's room, clothing worn by the child, together with an explanation of the likely course of the condition. Parents may be advised to share childcare with each other and friends/grandparents until this stage is passed in order to prevent physical/mental exhaustion.
• There is some evidence to support the substitution of cow's milk with soya milk, casein hydrolysate milk or low lactose milk. Other measures which require further investigation include sucrose solution, herbal tea, reduction of stimulation of the infant and bathing in warm water.¹⁰ Probiotics may be of benefit.¹¹
• One study found some benefit from the use of a minimal acupuncture technique.¹²

Drugs

There are no clear management guidelines for the treatment of infantile colic and no evidence-based cures.¹³ If parents feel unable to tolerate the child's crying until the condition has resolved spontaneously, symptoms may be relieved by the use of simethicone although evidence of benefit has not been borne out by randomised controlled trials.⁹ Drugs in the anti-muscarinic group, such as dicycloverine, have demonstrated effectiveness in clinical trials but their use is limited by adverse effects and they are contra-indicated in infants under the age of 6 months.^4,14 Other agents have been tried, although at present there is insufficient evidence to recommend any single agent for routine use in infant colic.¹⁵

Prognosis

One study found that 29% of infants aged 1-3 months suffered from colic but by 4-6 months of age the prevalence had fallen to 7-11%.⁹

Prevention

There is some evidence to suggest that the condition is linked to maternal smoking. These findings could act as a stimulus for health promotion advice during pregnancy.¹⁶