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 drinking enough. For this reason, there's no need to panic if you forget to bring a water bottle to the park once in awhile.

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 very 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.

Causes

In rare cases, not drinking enough fluids or sweating too much can cause dehydration. This is especially true in infants and young children. Their smaller body size naturally holds less fluid than an adult's body, so they are more susceptible to dehydration.

The most common way a child can lose fluids is if they have a stomach bug that's making them vomit, have frequent bouts of diarrhea, or both. In that case, it's almost inevitable they'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.

Signs

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

  • Their mouth and tongue seem dry.
  • They aren't urinating as often as usual. 
  • Their breathing and heart rate speed up slightly. 
  • Their arms and legs feel cool to the touch.
  • They appear listless, unusually cranky, or have less energy than normal.
  • Their eyes appear sunken or they don't produce as many tears when crying.
  • Their capillaries are slow to fill. You can test this by pressing on the nail bed of one of their fingers until the nail whitens. If it takes more than two seconds for the nail to return to it's normal pink color, the child is becoming dehydrated.
  • They have a slow skin turgor response. To check this, 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, their symptoms will worsen:

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

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

Prevention

Any time a child is throwing up a lot or has prolonged diarrhea, they're at risk of becoming at least a little dehydrated. You can make sure that doesn't happen by getting them to drink more fluids.

Clear liquids such as water, ice chips, or an oral electrolyte rehydration solution are best. Electrolyte solutions can be found at most drug stores. Be sure to follow the dosage guidelines provided by the American Academy of Pediatrics (AAP) based on your child's weight.

Don't give them milk or milk products. Try to avoid sports drinks as well because the extra sugars can make diarrhea worse.

While it may be tempting to try to get a sick kid to guzzle a lot at once, it will likely make their symptoms worse. A few teaspoons every 15 minutes or so should help them rehydrate quickly enough.

The AAP recommends building up to one-ounce of water an hour, then two ounces per hour until the child can drink normally. If they want to change to something else, fruit juice diluted with an equal amount of water or flat soda can be okay in small amounts.

A Word From Verywell

Keeping your children hydrated when they're playing or sick can prevent dehydration, so being aware of that and catching it early is the best course of treatment. If your child's symptoms worsen, do not hesitate to call a doctor and, if they are severe, go to the emergency room or call for an ambulance.

View Article Sources
  • American Academy of Pediatrics. Drinks to Prevent Dehydration in a Vomiting Child. HealthyChildren.org. 2015.
  • American Academy of Pediatrics. Treating Dehydration With Electrolyte Solution. HealthyChildren.org. 2015.
  • Popkin B, D'Anci K, Rosenberg I. Water, Hydration, and HealthNutritional Review. 2010; 68(8):439-458. https://doi.org/10.1111/j.1753-4887.2010.00304.x