Dehydration (Child)

What is dehydration?

Dehydration means that the body is losing too much fluid or not taking enough in, usually because of fever, overheating, or diarrhea. It’s both preventable and easily treatable, but you need to address the problem right away or it may become life-threatening.

How can I tell if my child is dehydrated?

These are the most common signs:

  • Decreased energy or playfulness
  • A sunken fontanel (soft spot) on a baby
  • A dry sticky mouth
  • No tears while crying
  • An elevated heart rate when there’s no fever
  • Decreased urine output
  • Dark yellow urine
  • For a child in diapers, failing to wet every two to three hours
  • For an older child, not urinating about once every four hours (during waking hours)

If you notice any of these symptoms, call your child’s doctor right away.

If your child continues to lose fluid, symptoms of serious dehydration may appear. If you see any of the following danger signs, get your child to an urgent care center immediately:

  • Sunken eyes
  • Cool, mottled hands and feet
  • Light-headedness
  • Lethargy, confusion, dizziness, or delirium

Why do children get dehydrated?

Kids have plenty of opportunity to get dehydrated, from playing outside on a scorching day to getting one of the many childhood illnesses. Here are some common culprits:

  • Fever and overheating. These are among the most frequent causes of dehydration. When your child has a fever, she sweats and water evaporates from her skin as her body tries to cool down. It’s surprising how much fluid children lose when they have a fever: For every degree her temperature rises above 100.4 F, your child loses 12.5 percent of her body fluid.

The air we breathe is humidified in the respiratory tract, which gives fluid another escape route. When children have fever or lung infections, they breathe fast and blow off extra fluid. Like fever, exercising on a hot day or just sitting in a stuffy, sweltering room can lead to sweating and fluid loss.

  • Diarrhea and vomiting. If your child has an intestinal illness, especially one known as acute gastroenteritis (AGE), she may lose fluid in the form of diarrhea. If she’s vomiting too, even more fluid is lost. If she has trouble keeping down liquids to replace these losses, the risk of dehydration rises.
  • Excess urination. More rarely, diseases like diabetes, kidney disease, and certain conditions affecting hormones and the nervous system can lead to increased fluid loss.
  • Decreased fluid intake. Sore throats and other ailments, such as hand, foot, and mouth disease, can cause so much pain that children sometimes stop drinking.

What should I do if my child has diarrhea?

Infants with diarrhea need special care, because they can become severely dehydrated in less than 24 hours. Call your child’s doctor immediately if you see signs of dehydration such as sticky saliva, dark yellow urine, weakness, dry diapers, or cool, mottled hands or feet.

If your child has moderate to severe diarrhea, she needs an electrolyte solution like Pedialyte, Infalyte, or Kaolectrolyte. Give her a few sips every few minutes. Call your doctor immediately if you see the signs of dehydration listed above.

If your child is older, you can increase her intake of liquids by giving her sips of water or ice chips. Avoid very sweet liquids, don’t give her broth, fruit juice, milk, soda, or sports drinks, and avoid over-the-counter antidiarrhea medicines.

How can I prevent other kinds of dehydration?

If your child has a fever, offer plenty of liquids — some kids do better with ice-cold drinks, while others may find warm liquids more soothing. Avoid citrus drinks like orange juice and grapefruit juice; they’ll sting and burn the irritated tissue of a sore throat. If she’s having trouble swallowing, you can use a pain medication like acetaminophen. (To guard against Reye’s syndrome, a rare but potentially life-threatening disorder, never give aspirin to children or teenagers.)

If a child is vomiting, it is important to give her small amounts of fluid frequently to restore the fluid she has lost. A couple of hours after a vomiting episode, give her 2 ounces of water every half hour or so, up to four times. If she’s able to drink the water without vomiting again, give her 2 ounces of electrolyte solution and alternate with water every half hour. If she can retain the water and the electrolyte solution, add half-strength formula or milk and increase the amount slowly to 3 or 4 ounces every three or four hours. If vomiting continues, withhold all fluids for an hour and start again with a smaller amount.

During hot weather and exercise, of course, your child needs more fluids than usual. Kids generally need 44 to 88 ounces of fluid per day; for every 15 minutes of heavy activity, add another 4 to 6 ounces of water (for a child up to 90 pounds). Have your child load up on fluids two hours before exercising, and then offer her liquids every 10 to 20 minutes whether she’s thirsty or not. Again, avoid sports drinks: The relatively high sugar content of some of these beverages can cause cramping, nausea, and diarrhea.

When should I call my pediatrician?

If your child shows symptoms of dehydration — dark urine, tearless crying, sticky mouth, lethargy, and mottled hands and feet — and is getting worse despite your care, contact your pediatrician. Severely ill children may need intravenous fluids.

Further Resources

Mayo Clinic

Pantell, Robert H. M.D., James F. Fries M.D., and Donald M. Vickery M.D. Taking Care of Your Child: A Parent’s Illustrated Guide to Complete Medical Care, Eighth Edition. 2009. Da Capo Lifelong Books.


US Federal Drug Administration. Preventing Dehydration in Children. 1996.

Nemours Foundation, Dehydration.

American Academy of Pediatrics. Diarrhea. Updated August 2010.

American Academy of Pediatrics, Treating Vomiting. Updated August 2010.

American Academy of Pediatrics. Guidelines for Pediatricians: Exertional Heat-Related Illness. May 2000.

© HealthDay

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