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Dehydration in Children


Christopher P. Raab

, MD, Sidney Kimmel Medical College at Thomas Jefferson University

Reviewed/Revised Feb 2023
Topic Resources

Dehydration is loss of water from the body, usually caused by vomiting and/or diarrhea.

Causes of Dehydration in Children

Symptoms of Dehydration in Children

Dehydrated infants need medical care right away if

  • The soft spot on their head is sunken.

  • Their eyes are sunken.

  • They have no tears when they cry.

  • Their mouth is dry.

  • They are not producing much urine.

  • They have reduced alertness and are underactive (lethargic).

Mild dehydration typically causes a dry mouth and lips and increased thirst, and children may urinate less frequently.

Moderate dehydration causes children to be less interactive or playful, have a dry mouth, and urinate less frequently. Moderate and severe dehydration can cause a rapid heartbeat and lightheadedness.

Severe dehydration causes children to become sleepy or lethargic, which is a sign they must be evaluated by a doctor or taken to a hospital or urgent care clinic right away. They have no tears. They may develop a bluish discoloration to the skin (cyanosis Cyanosis Cyanosis is a bluish or grayish discoloration of the skin resulting from an inadequate amount of oxygen in the blood. Cyanosis occurs when oxygen-depleted (deoxygenated) blood, which is bluish... read more ) and breathe rapidly. Sometimes dehydration causes the concentration of salt in the blood to fall or rise abnormally. Changes in salt concentration can make the symptoms of dehydration worse and can worsen lethargy. In severe cases, the child can have seizures Seizures in Children Seizures are a periodic disturbance of the brain’s electrical activity, resulting in some degree of temporary brain dysfunction. When older infants or young children have seizures, they often... read more or coma Stupor and Coma Stupor is unresponsiveness from which a person can be aroused only by vigorous, physical stimulation. Coma is unresponsiveness from which a person cannot be aroused and in which the person's... read more or suffer brain damage. Severe dehydration can be fatal.

Diagnosis of Dehydration in Children

  • Examination by a doctor

  • Sometimes blood and urine tests

Doctors examine children and note whether they have lost body weight. A loss in body weight over only a few days is very likely caused by dehydration. The amount of weight lost, if known, helps doctors decide whether the dehydration is mild, moderate, or severe.

For moderately or severely dehydrated children, doctors usually do blood and urine tests to determine the levels of electrolytes in their body, the degree of dehydration, and the amount of fluid replacement required.

Treatment of Dehydration in Children

  • Replacement of lost fluids

Dehydration is treated with fluids containing electrolytes, such as sodium and chloride.

If dehydration is mild, fluids are generally given by mouth. Special oral rehydration solutions are available but are not always necessary for children who have had only mild diarrhea or vomiting.

Treatment of dehydration in children of any age who are vomiting is more effective if the child is first given small, frequent sips of fluids about every 10 minutes. The amount of fluid can slowly be increased and given at less frequent intervals if the child can keep the fluid down without vomiting. If diarrhea is the only symptom, larger amounts of fluid can be given less often.

If children have both vomiting and diarrhea, they are given small, frequent sips of fluids containing electrolytes. If this treatment increases the diarrhea, children may need to be hospitalized for fluids given by vein (intravenously).

Infants and children who are unable to take in any fluids, or who develop listlessness and other serious signs of dehydration, may require more intensive treatment with fluids and electrolytes given intravenously or electrolyte solutions given through a thin plastic tube (nasogastric tube) that is passed through the nose and down the throat until it reaches the stomach or small intestine.


In infants, dehydration is treated by encouraging an infant to drink fluids that contain electrolytes. Breast milk contains all the fluids and electrolytes an infant needs and is the best treatment when possible.

If an infant is not breastfeeding, oral rehydration solution (ORS) should be given. ORS contains specific amounts of sugars and electrolytes. ORS can be bought as powders that are mixed with water or as premixed liquids at drug or grocery stores without a prescription. The amount of ORS to give a child in a 24-hour period depends on the child’s weight, but generally should be about 1½ to 2½ ounces of ORS for each pound the child weighs (100 to 165 milliliters per kilogram). Thus, a 20-pound infant should drink 30 to 50 ounces total over 24 hours (a 10-kilogram infant should drink 1,000 to 1,650 milliliters total over 24 hours).

Older children

Children older than 1 year may try small sips of clear broths or soups, clear sodas, gelatin, or juice diluted to half-strength with water, or popsicles. Plain water, undiluted juice, or sports drinks are not ideal for treating dehydration at any age because the salt content of water is too low and because juice has a high sugar content and ingredients that irritate the digestive tract.

ORS is an alternative, particularly for moderate dehydration.

If children are able to tolerate fluids for 12 to 24 hours, they may resume their normal diet.

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