Q. My baby is up all night crying, and I'm at my wit's end. Is it colic  -- and, if so, what can I do?

A. Having had colicky babies, I know all too well how exhausting it can be. On top of being sleep-deprived and frustrated, it's terrible to see your infant hurting. I wish I'd known from the start what I know now: Colic is a particular type of crying (frequent, prolonged outbursts) often caused by abdominal pain. Two reasons a baby's tummy might hurt that badly, both treatable:

Possible cause

Reflux, also known as gastroesophageal reflux disease (GERD), occurs when the circular band of muscle where the esophagus joins the stomach hasn't fully matured. This allows stomach acid to flow into the esophagus, irritating the lining and causing heartburn.

Signs

In addition to inconsolable crying: repeatedly spitting up after feeding, writhing in pain, frequent wet or sour burps, trouble sleeping

Treatment

Nurse as long as possible, since breast milk empties from the stomach faster than formula and, in turn, will less likely lead to reflux. Feed your baby twice as often, giving him half as much, especially if you're bottle-feeding. And with either feeding method, keep your baby upright for at least half an hour after he's finished and elevate the head of his crib between 30 and 45 degrees. If these treatments don't work, your doctor may prescribe medication to reduce stomach acid.

Possible cause

An allergy to a component of formula or something in a breastfeeding mother's diet

Signs

Same as reflux, but often accompanied by diarrhea and a raised rash, primarily on the face and trunk

Treatment

If you're bottle-feeding, try a hypoallergenic formula (and offer smaller, more frequent feedings). If breastfeeding, eliminate cow's milk  -- the most common infant allergen  -- from your diet for at least a week to see if your baby feels better. Other typical allergens are soy, wheat, eggs, and nuts.

Of course, not all babies will respond to these methods, since colic can be caused by many things. But whatever the reason for the constant crying, most babies will outgrow it within three to six months.

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