Dehydration in Infants and Toddlers

By , August 27th 2013. Last reviewed 12th March 2018.

Causes of Dehydration in Small Children

The most common cause of dehydration in infants and toddlers is diarrhea due to viral gastroenteritis (stomach flu) [5]. Other common causes include:

  • Excessive sweating due to fever or hot climate
  • Refusal to drink due to nausea or a sore throat
  • Insufficient breastfeeding or formula-feeding
  • Repeated vomiting due food poisoning or other infection
  • More causes of dehydration

Symptoms and Signs

Symptoms and signs of dehydration in infants include dry mouth, less tearing when crying, sunken eyes, irritability or drowsiness, fewer wet diapers per day, strong yellow urine, poor skin turgor and constipation (more in Chart 1).


A doctor can make a diagnosis of dehydration in small children from the physical signs and observations of their parents (Chart 1). Blood and urine tests are usually performed only in severe dehydration.

Chart 1. The Assessment of Dehydration in Infants



(1-5% loss of body weight)


(6-10% loss of body weight)


(>10% loss of body weight)

Consciousness Alert Lethargic Sleepy or comatose
Heart rate Slightly increased Increased Very increased
Breathing rate Normal Increased Increased
Blood pressure Normal Normal Decreased
Pulse Normal Weak Faint
Eyes Normal Sunken; less tearing Very sunken; no tears
Mouth and lips Normal Dry Chapped
Skin turgor test Normal Delayed (1-2 sec) Slow (>2 sec)
Capillary refill <2 sec 2-4 sec >4 sec
Urine excretion Slightly decreased Decreased (>6 hours without a wet diaper) Very decreased or absent
Fontanel (the soft spot on the top of the head) Normal Depressed Sunken

Chart 1. Reference: 1


Mild or moderate dehydration in infants and children under four years of age should be treated with oral rehydration solutions (ORS) and NOT with plain water [6]. Severe dehydration usually requires intravenous infusion in a hospital.

Chart 2. Oral Rehydration Solution (ORS) by WHO and UNICEF

Sodium chloride (NaCl) 2.6 Sodium 75
Glucose 13.5 Chloride 65
Potassium chloride 1.5 Glucose 75
Trisodium citrate 2.9 Potassium 20
Citrate 10
Total osmolarity 245

Chart 2. The composition of Oral Rehydration Solution (ORS) by WHO (World Health Organization) and UNICEF [2]

Most commercially available oral rehydration solutions contain a little less sodium and a little more glucose than the WHO/UNICEF ORS but are appropriate to treat dehydration [6].

A Homemade ORS

A recipe recommended by World Health Organization [3,4]:

  • 1 liter of water, boiled and cooled (if boiling is not possible, use the cleanest available source of water, like bottled water)
  • 1/2 level teaspoon table salt (3 grams of sodium chloride)
  • 6 level teaspoons table sugar (25 grams of sucrose)

How much ORS should you give to a dehydrated INFANT and how fast?

Initially, give ORS slowly, like 1 teaspoon (5 mL) per 1-2 minutes, to avoid inducing vomiting, or more if a baby can tolerate it [6,12]. Give ORS as long as a child has diarrhea or until he/she regains his/her usual body weight and his/her urine becomes clear [6]. Vomiting is not the reason to stop ORS, but if a baby vomits, wait 10-15 minutes and continue with ORS [6].

You should discard ORS after it stays more than 12 hours at the room temperature or after 24 hours in the refrigerator.

How much fluid should you give to a dehydrated TODDLER and how fast?

Mildly dehydrated toddlers (1-4 years) can drink as much ORS as they want. If an ORS is not available, they can drink plain water, herbal tea or diluted fruit juice as long as they eat some salted food [11].

Dehydrated children older than 4 years do not need ORS and can drink plain water or other appropriate beverages [11].

In rare occasions, a dehydrated child might want to drink large amounts (several liters) of fluid with no or little sodium (water, tea, fruit juice, cola), which could be due to psychogenic polydipsia. Excessive drinking may lead to life-threatening hyponatremia.

Infants and Toddlers With Diarrhea

Infants and toddlers with prolonged diarrhea should receive ORS and possibly zinc supplements as prescribed by a doctor [10]. In bacterial, but not viral, diarrhea, a doctor will usually prescribe antibiotics. Antidiarrheal drugs are not recommended [6,13].

When a child has severe diarrhea, you might not be able to give him/her enough oral rehydration solution (ORS) to replace the water he/she has lost, so in this case, call a doctor and continue with ORS.

Rehydration plan for cholera by

Fluids NOT appropriate to treat moderate or severe dehydration in infants and toddlers include plain water, tea, coffee, soft drinks (cola, soda), sport, energy and alcoholic drinks. These beverages contain a lot of sugar, caffeine or alcohol (which may trigger diarrhea) or too little sodium (which can result in hyponatremia) [13].

What should a baby or toddler eat during dehydration?

A dehydrated baby should continue with breastfeeding or full-strength reduced-lactose or lactose-free milk formula, but he/she should additionally receive oral rehydration solution [6,8,13].

Dehydrated toddlers should eat what they like. Complex carbohydrate foods (potatoes, bread, noodles, saltine crackers, cereals), lean meats, fruits (such as bananas) and vegetables should be encouraged. Fatty foods and foods simple sugars (sweets, fruit juices) should be avoided to prevent worsening of diarrhea [6,13].

When to call a doctor?

Call a doctor when a dehydrated child:

  • Is younger than 6 months
  • Has signs of severe dehydration (Chart 1)
  • Refuses to drink or does not seem to become rehydrated after giving ORS or refuses to eat for more than a day
  • Vomits persistently or has severe (>10 stools/day), prolonged (>1 week) or bloody diarrhea
  • Has body temperature greater than 100.4 °F (38 °C)
  • Is lethargic, does not respond to physical stimuli (impaired consciousness) or has seizures (involuntary movements)
  • Has pale, cool and sweaty skin, which are symptoms of hypovolemic shock or heat exhaustion.
  • Reference: [9]

Intravenous Infusion

When an infant or toddler can not drink, vomits repeatedly or is severely dehydrated (sunken fontanels and eyes), he or she may need intravenous fluid infusion, in most cases the physiological solution (0.9% NaCl) [6].


In most circumstances, including hot climates, regular breastfeeding or consuming formula should be enough to prevent dehydration of a healthy infant. Doctors do not recommend antidiarrheal drugs for small children with diarrhea because they were not proven effective and may have significant side effects [6].

Prognosis and Statistics

Dehydration resulting in 15% loss of body weight or more (>1.5 kg in a 10 kg child) is life-threatening.

More than one million of young children die each year from dehydration due to diarrhea [7].