Irritable Child, Uncertain Cause

Fussiness with irritable behavior is common among children. It may last from a few hours up to a few days. It may be due to some type of change that your child is adjusting to. This may include changes in the child's surroundings (new location or air temperature) or feeding habits (changes in type of food given or feeding schedule). It may be a physical change (new body sensations) as the child develops.

Most often the fussy behavior goes away as the child adjusts to the new situation. Sometimes, though, fussy behavior is an early sign of a physical illness. Quite often such an illness is minor, such as teething, or a cold or other viral illness. Sometimes the cause can be serious enough to require further exam and treatment.

Although the exam today did not show any signs of a serious illness, it may take another 12 to 24 hours for the usual signs of an illness to appear. Continue watching for the warning signs listed below.

Home care

  • Feeding. Your child’s appetite may be poor. It's OK to go without solid food for the next 24 hours, as long as the child drinks lots of fluid.

  • Fluids. Continue giving the usual fluids (such as milk, formula, and juices). Give extra fluids if your child does not want to eat solid foods.

  • Activity. Encourage rest, quiet play, and frequent naps during the next 24 hours.

  • Sleep. A change in usual sleep patterns, with sleeplessness or waking up often, is not unusual. You may need to spend extra time to comfort your child during this time.

  • Medicine. Follow the healthcare provider’s instructions on the use of over-the-counter pain medicines such as acetaminophen for fever, fussiness, or discomfort. Also note:

    • If your child has chronic liver or kidney disease or ever had a stomach ulcer or gastrointestinal bleeding, talk with the provider before using any of these medicines.

    • Don't give ibuprofen to a child age 6 months or younger.

    • Don’t give aspirin to a child younger than age 19 unless directed by your child’s provider. Taking aspirin can put your child at risk for Reye syndrome. This is a rare but very serious disorder that most often affects the brain and the liver.

Follow-up care

Follow up with your child’s healthcare provider, or as advised. Continued use of pain medicines such as acetaminophen or ibuprofen may hide symptoms of a more serious illness. If your child continues to be fussy, and the cause of the symptoms isn't clear, contact the provider.

When to get medical advice

Unless your child's healthcare provider advises otherwise, call the provider right away if your baby:

  • Has a fever (see Fever and children, below)

  • Is fussy or cries and cannot be soothed

  • Doesn't feed well or doesn't gain weight

  • Repeatedly vomits or has diarrhea, or pulls at an ear

  • Has blood in the stools or vomit (black or red color)

  • Shows an unexpected change in their crying pattern

  • Becomes drowsy or confused

  • Shows signs of belly (abdominal) pain, such as drawing the legs up to the chest while crying

  • Cries without stopping for more than 2 hours

  • Breathing becomes faster:

    • Birth to 6 weeks: over 60 breaths/minute

    • 6 weeks to 2 years: over 45 breaths/minute

    • 3 to 6 years: over 35 breaths/minute

    • 7 to 10 years: over 30 breaths/minute

    • Older than 10 years: over 25 breaths/minute

Fever and children

Use a digital thermometer to check your child’s temperature. Don’t use a mercury thermometer. There are different kinds and uses of digital thermometers. They include:

  • Rectal. For children younger than 3 years, a rectal temperature is the most accurate.

  • Forehead (temporal). This works for children age 3 months and older. If a child under 3 months old has signs of illness, this can be used for a first pass. The provider may want to confirm with a rectal temperature.

  • Ear (tympanic). Ear temperatures are accurate after 6 months of age, but not before.

  • Armpit (axillary). This is the least reliable but may be used for a first pass to check a child of any age with signs of illness. The provider may want to confirm with a rectal temperature.

  • Mouth (oral). Don’t use a thermometer in your child’s mouth until he or she is at least 4 years old.

Use the rectal thermometer with care. Follow the product maker’s directions for correct use. Insert it gently. Label it and make sure it’s not used in the mouth. It may pass on germs from the stool. If you don’t feel OK using a rectal thermometer, ask the healthcare provider what type to use instead. When you talk with any healthcare provider about your child’s fever, tell him or her which type you used.

Below are guidelines to know if your young child has a fever. Your child’s healthcare provider may give you different numbers for your child. Follow your provider’s specific instructions.

Fever readings for a baby under 3 months old:

  • First, ask your child’s healthcare provider how you should take the temperature.

  • Rectal or forehead: 100.4°F (38°C) or higher

  • Armpit: 99°F (37.2°C) or higher

Fever readings for a child age 3 months to 36 months (3 years):

  • Rectal, forehead, or ear: 102°F (38.9°C) or higher

  • Armpit: 101°F (38.3°C) or higher

Call the healthcare provider in these cases:

  • Repeated temperature of 104°F (40°C) or higher in a child of any age

  • Fever of 100.4°F (38°C) or higher in baby younger than 3 months

  • Fever that lasts more than 24 hours in a child under age 2

  • Fever that lasts for 3 days in a child age 2 or older

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