Infant Colic, or the Period of PURPLE Crying

Today, the term “colic” is increasingly being replaced by “the Period of PURPLE Crying.” This is because the word “colic” comes from Greek and means “large intestine,” and studies conducted in the 1900s linked crying to gastrointestinal dysfunction. Many theories about this condition are now being considered, but no single cause has been identified.

Other terms used interchangeably with colic include:

• “crying behavior,”
• “excessive crying,”
• “unsettled infant behavior.”

Association With Psychosocial Factors

This type of crying has been associated with maternal smoking during pregnancy and the postpartum period, older maternal age, family stress, parents’ lack of confidence in caring for their baby, parental depression, and the baby being the family’s first child.

“Various parental psychosocial factors, including family stress, maternal anxiety, and the transmission of tension from mother to infant, may be associated with colic. Prospective studies support an association between maternal anxiety disorder, emotional stress, or a maternal history of depression in early pregnancy and symptoms of depression in the father during pregnancy.”

“Associations have been observed between colic and dissatisfaction with the marital relationship, parents’ perceived stress, lack of parental self-confidence during pregnancy, dissatisfaction with the birth experience, and the level of family stress.”

Possible Causes and Theories

The cause is unknown: no association has been found with CMPA, lactase deficiency, gastrointestinal immaturity (one theory proposed that fermentation of unabsorbed carbohydrates by bacteria in the large intestine leads to excessive gas production), intestinal hypermotility, or autonomic imbalance.

Changes in the fecal microbiota may play a role in the development of infant colic (PURPLE Crying).

Several studies have found differences in the gut microbiota between infants with colic and control infants, particularly in Klebsiella, anaerobic gram-negative bacteria, coliform bacteria, Escherichia coli, and lactobacilli.
The role of the fecal microbiota is supported by randomized trials in infants with colic in which treatment with L. reuteri reduced crying time and was associated with changes in the gut microbiota (increased Lactobacillus and decreased E. coli).

Infant colic (PURPLE Crying) may be an early manifestation of migraine in children. In the studies conducted, migraine without aura was more common among adolescents who had infant colic than among adolescents who had not.

One theory suggests that crying at the end of the day is a release after a long day of exposure to external stimuli and a means of maintaining homeostasis.

How a Presumptive Diagnosis Is Made

A presumptive diagnosis of infant colic (PURPLE Crying) can be made in a healthy infant younger than 3 months who cries for no apparent reason for ≥3 hours a day on ≥3 days a week. In practice, however, we do not wait 3 weeks and make the diagnosis when episodes recur.

Criteria for the Period of PURPLE Crying

Criteria for the Period of PURPLE Crying:

• P — peak of crying, crying begins in the second week and peaks at 6–8 weeks, after which it gradually decreases.
• U — unexpected — unpredictable, it is impossible to predict when an episode of crying will begin or end. Episodes usually have a clear beginning and end. The onset is generally unrelated to what the infant was doing immediately before the “episode.” The infant may have been happy, fussy, feeding, or even sleeping.
• R — resists soothing — cannot be soothed. The infant is difficult to soothe regardless of what the parents do. There may be periods when the crying subsides but the infant remains unsettled. Relief may come after passing gas or stool.
• P — pain-like — appears to be in pain. The crying may sound as though the infant is in pain or screaming rather than crying. The episode may be accompanied by facial flushing, pallor around the mouth, a tense or distended abdomen, drawing up the legs, clenching the fingers, tensing the arms, or arching the back.
• L — long lasting — prolonged, crying may continue for several hours.
• E — evening — later in the day, this crying is more common in the second half of the day.

Characteristic Features and Duration

Characteristic features of colic include episodes of crying that begin and end without an apparent reason in an infant with normal growth, development, and physical examination findings.

PURPLE Crying resolves by three months in 60% of infants and by four months in 90% of infants.