How to Tell If a Child Is Dehydrated

The Dehydration Symptoms All Parents Should Know

dehydrated girl in hammock outside
Dejan Ristovski/Stocksy United

Kids don't get dehydrated easily. And when they do, it's usually because they're losing fluid, not because they aren't downing enough. (So don't panic if you forget to bring a water bottle to the park once in awhile.) The most common way a child can lose fluids is if she has a tummy bug that's making her vomit, has frequent bouts of diarrhea, or both. In that case, it's almost inevitable she'll wind up at least a little dehydrated.

Less often, dehydration may be caused by a chronic condition. For example, the high levels of blood sugar in a child who has diabetes can cause her to urinate more often than usual.

Whatever brings it on, the signs of early dehydration in a child can be sneaky. In fact, a kid who needs more fluid may not even seem all that thirsty, if at all. But because severe dehydration can have serious complications, it's important to know what to look for well before a child reaches that point.

Signs of Dehydration in a Child

If a child shows any of these symptoms of mild to moderate dehydration, check in with her pediatrician or family doctor to find out what to do:

  • Her mouth and tongue seem dry.
  • She isn't peeing as often as usual. 
  • Her breathing and heart rate speed up slightly. 
  • Her arms and legs feel cool to the touch.
  • Her eyes appear sunken.
  • Her capillaries are slow to fill. You can test this by pressing on the nail bed of one of her fingers until the nail whitens. If it takes more than two seconds for the nail to pink back up, the child is becoming dehydrated.
  • She'll have a slow skin turgor response. Gently squeeze a fold of skin on her belly, hold it for a few seconds, and release. If it takes longer than two seconds for the skin to return to normal, her fluid levels are starting to go down.

As a child becomes more dehydrated, her symptoms will worsen:

  • She may have trouble drinking or even be unable to drink.
  • Her mouth and tongue will appear dry and parched.
  • She'll rarely urinate or will stop peeing altogether.
  • Her heart rate will speed up, but her pulse will become weak and she'll begin breathing heavily.
  • Her arms and legs will feel cool and her skin will look mottled.
  • It will take more than a couple of seconds for her capillaries to refill.
  • It will take more than 2 seconds for a fold of skin on her belly to return to normal.

If a child gets to this stage, it's considered an emergency. She may need to be hospitalized so she can receive fluids intravenously.

The Easiest Way to Prevent Dehydration

Any time a child is throwing up a lot or has prolonged diarrhea, she's at risk of becoming at least a little dehydrated. You can make sure that doesn't happen by getting her to drink more fluids. That's it. Clear liquids are best: Water, ice chips, or an oral electrolyte rehydration solution, which you can buy at the drugstore, are best. Don't give her milk or milk products. But here's the trick: It may be tempting to try to get a sick kid to guzzle a lot at once, but even if she's willing to do it, it will likely make her symptoms worse. A few teaspoons every 15 minutes or so should help her to rehydrate quickly enough.


Popkin, B.; D'Anci, K; and Rosenberg, I. "Water, Hydration, and Health." Nutritional Review. 2010; 68(8):439-458.

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