Diagnosis of colic by a pediatrician is generally made based on a parent’s description of the infant’s behavior. Thus, parents may wish to keep a diary of their child’s crying episodes (e.g., when they occur, and for how long) as well as the infant’s physical development (e.g., weight gain). A child with colic will be otherwise healthy and experiencing normal weight gain.

Parents can expect a physician to collect a medical history, as well as information regarding the general health of their child (e.g., the child’s growth, diet, stool, urination and sleeping patterns). Questions a pediatrician may ask include:

• When does the crying occur and for how long does it last? (Crying that occurs after feedings may indicate reflux or allergies.)
  
  
• What does the cry sound like? (Cries from a baby with colic will sound different than the cries used to indicate hunger or fatigue.)
  
  
• What is done when the baby cries? (This may determine what methods of soothing the child are effective.)

A pediatrician may also conduct a physical examination of the child. This is usually done to rule out other possible medical conditions that may be causing the crying (e.g., reflux, allergies, intestinal obstruction, urinary infections, intussusception). If other conditions are suspected, a physician may recommend additional tests, including blood tests, x-rays and other imaging tests.

In the absence of any other cause, physicians may apply the “rule of three” in diagnosing colic:

• Crying occurs for three consecutive hours or more per day
  
  
• Crying episodes occur at least three days a week
  
  
• Crying episodes persist for more than three weeks (this criteria is sometimes not included, since some parents do not wait three weeks before consulting a physician)