Irritable Infant: Why Is My Baby So Fussy?

What counts as an irritable infant

All babies cry. Crying usually increases from about 2 weeks of age, peaks at around 6 to 8 weeks, often in the late afternoon and evening, and settles by 3 to 4 months. A baby is described as irritable when they are fussier than their own normal, cry for long stretches, or cannot be calmed by the usual comforts.

The most useful question is: is this different from how my baby usually is? A sudden change, especially with any other symptom, matters more than the amount of crying alone.

Common, non-serious causes

• Hunger: the commonest reason. Newborns feed 8 to 12 times a day, and growth spurts at around 2 to 3 weeks, 6 weeks and 3 months bring extra hunger.
• Tiredness and overstimulation: babies cannot easily switch off. Busy rooms, visitors and noise build up to evening fussing.
• Wind and swallowed air: from fast feeding or crying. Burping during and after feeds helps.
• Discomfort: a wet or dirty diaper, feeling too hot or cold, tight clothing, or a hair wrapped around a finger or toe (check the fingers, toes and penis in an inconsolable baby).
• Colic: crying for more than 3 hours a day, on more than 3 days a week, in a healthy baby who is growing well. Episodes often come at the same time each day, with clenched fists, a red face and drawn-up legs. The cause is unclear, and it settles by 3 to 4 months.
• Teething: from about 6 months, causing drooling, chewing and mild irritability for a few days per tooth. Teething does not cause high fever or diarrhea.
• A cold: a blocked nose makes feeding and sleeping harder because babies prefer to breathe through the nose.
• After vaccinations: fussiness and a mild fever for 24 to 48 hours are common.

Medical causes of an irritable infant

Irritability is sometimes the first and only sign of serious infection in young babies, before a high fever or obvious symptoms appear. That is why doctors take any fever in a baby under 3 months seriously.

When to worry about an irritable baby

Get medical advice the same day if your baby:

• is under 3 months and has a temperature of 38 °C (100.4 °F) or higher
• is feeding much less, or has fewer wet diapers
• has a cry that sounds different: weak, high-pitched or moaning
• is unusually sleepy, floppy or hard to wake
• cannot be settled by anything for more than 2 to 3 hours
• vomits repeatedly or has blood in the stool

Trust your instincts. If your baby seems unwell in a way you cannot explain, it is reasonable to be seen.

How a doctor assesses a fussy baby

The doctor will ask about the pattern and timing of crying, feeding, wet and dirty diapers, vomiting, stool, fever, weight gain, and how you are coping. They will undress the baby to check the skin, soft spot, ears, throat, chest, belly, hips, groin, fingers and toes. Many babies need no tests. A urine sample is often checked if there is fever, and young babies with fever may need blood tests and sometimes a lumbar puncture.

How to soothe an irritable infant

1. Check the basics: feed, burp, change the diaper, adjust clothing.
2. Hold and move: rocking, walking, a baby carrier, or a car or stroller ride.
3. Reduce stimulation: a dim, quiet room. Some babies settle with steady white noise or a "shushing" sound.
4. Swaddle a young baby in a thin wrap, with room for the hips to bend, and stop once they start trying to roll. Always place the baby on their back to sleep.
5. Offer a pacifier if you use one.
6. A warm bath or gentle tummy massage.

Gripe water, herbal remedies and simethicone drops have little good evidence for colic. Do not give any medicine to a baby under 3 months without advice. Acetaminophen (paracetamol) can be used for fever or teething pain in older babies at the dose for their weight on the label. Do not give aspirin to babies or children. Do not give honey to babies under 12 months.

If you breastfeed and your baby has signs of milk allergy, a doctor may suggest you cut dairy from your diet for a trial period. Do not change formula repeatedly without advice.

Frequently asked questions

What causes an irritable infant?

The commonest causes are hunger, tiredness, wind, overstimulation, colic in the first months, teething and minor colds. Medical causes include ear and urinary infections, reflux, cow's milk protein allergy and constipation. Rarely, irritability is a sign of serious infection such as meningitis, or of intussusception.

How much crying is normal for a baby?

Healthy newborns often cry 1 to 3 hours a day in total, peaking at around 6 to 8 weeks. Crying more than 3 hours a day, 3 days a week, in a well, growing baby fits the definition of colic, which usually settles by 3 to 4 months.

When should I worry about a fussy baby?

Worry if fussiness comes with fever (any fever under 3 months), poor feeding, fewer wet diapers, vomiting, a weak or high-pitched cry, floppiness, a bulging soft spot, a rash that does not fade or breathing problems. Also seek help if crying is unlike your baby's usual pattern.

Can teething make a baby irritable?

Yes. Teething can cause fussiness, drooling, chewing and disturbed sleep for a few days around each tooth, usually from about 6 months. It does not cause high fever, diarrhea or a rash on the body, so look for another cause if these appear.

Can reflux make a baby irritable?

Most babies spit up without distress, and that is normal. Reflux disease is more likely if a baby arches, cries during most feeds, refuses feeds or gains weight poorly. A doctor can advise on feeding changes, and medicine is only used in selected cases.