Why is dehydration in children dangerous? What are the symptoms?

Why is dehydration in children dangerous? What are the symptoms?
Photo source: Getty images

Dehydration is becoming a hot topic again, especially during the hot days of summer. Of course, various illnesses can cause it, for example, with diarrhoea or fever. It complicates life for adults, but much more so for children. It develops more quickly in them, and just as suddenly, it also complicates.

Dehydration in children can be dangerous, it occurs more quickly than in adults and is characterized by some peculiarities.

You ask:
Why is dehydration dangerous in children?
What are the most common causes? Is it only due to diarrhoea?
How does dehydration in children manifest itself?
What to do about dehydration?

Water is the basis for the origin and maintenance of life. Diet is important, but without water our bodies decline much more rapidly. It is reported that water makes up approximately 75% of our bodies. The rest is attributed to solids.

In an adult or elderly person, the percentage of water is 55-60%. In children, the percentage of water content is higher. It is approximately 75-80% in newborns. This figure also shows that our children are more sensitive to water management than adults.

Dehydration means that there is a deficiency of water in the body. This is caused by a reduced intake or, on the contrary, an excess loss of fluid from the body.

For more information on dehydration, see the magazine article that lists the symptoms of dehydration, and also the article on the symptom itself.

Dehydration in children and its most common causes

The causes of dehydration in children are the same as in adulthood. But childhood age has some peculiarities. Rotavirus infections are common in the youngest children, which cause diarrhea and thus the risk of dehydration.

In addition to rotavirus infections, diarrhoea is also encountered in salmonellosis, malabsorption syndrome, lactose intolerance or celiac disease. Irritable bowel syndrome can also be a cause of diarrhoea in children, as well as stress and psychological stress.

The child is sick, bedridden, on an IV.
A common cause of dehydration is diarrhea. Photo source: Getty Images

Other examples of fluid loss are vomiting, increased body temperature or fever. Not only various disease causes can cause a lack of fluid in the body. This also occurs as a consequence of insufficient water intake.

Children forget to drink fluids during the hot summer months, especially during play and sports. In this case, it is the parent's irreplaceable task to supervise the correct drinking regime, as well as the correct habit of regular drinking.

How much water does a child need to avoid dehydration?

For each period of childhood, there are, of course, different recommended values. A newborn and a breastfed child receives fluids from breast or artificial milk. For older infants, other fluid is already ranked. The best is pure, infant water, but also teas designed for the appropriate age.

A small child reaches for a glass of water on the table
Distinguish between appropriate and inappropriate drinks. Source photo: Getty Images

For older babies, plain water, milk, fruit juices should predominate. If you choose juices, fresh 100% juices are best. These can be diluted 1:1 with plain water. In the representation of minerals, low-mineralised waters can be used.

Unsuitable are sweetened bottled waters, over-saturated mineral waters, black tea, energy drinks and of course coffee and alcohol. Sugary waters and energy drinks also mean excess intake of unnecessary energy. This can be stored as fat and can cause childhood overweight or obesity. This carries other serious health risks.

Tip: For more information, see the magazine article Obesity in children and young people, what to do about it?

So much for appropriate and inappropriate beverages. The following table shows the recommended fluid intake values for different periods of childhood.

Age Amount of fluid in millilitres
per kilogram per 24 hours
Amount of fluids
per 24 hours in millilitres
3 days 80-100 250-300
2 weeks 125-150 400-500
3 months 140-150 750-850
6 months 130-145 950-1100
9 months 130 1000-1250
1 year 120-132 1100-1300
2 years 100-125 1350-1500
4 years 90-110 1600
10 years 70-85 2000-2500
12 years 70-100 2100-2500
18 years 40-60 2200-2700

How is dehydration assessed in children?

In children, the assessment of dehydration is more complicated than in adults. Dehydration also has three grades. Weight (percent weight loss), the child's general appearance and speech, age, pulse, respiration, skin tension (turgor), eyes, general appearance of mucous membranes, and urine are assessed.

Clinically, dehydration is assessed according to the table

Symptom Mild
Weight loss in % 3-5 3-9 10% or more
Infant manifestations
(up to 1 year)
lively, restless restless, irritable, lethargic Sleepy, flaccid muscles, cold extremities,
blue or cyanotic fingertips, disturbed consciousness
Child's manifestations
over 1 year
thirsty, lively, restless thirsty, lively, restless cold and cyanotic fingertips, even convulsions
Pulse normal weak, rapid. threadlike, accelerated
Systolic pressure normal may be low low to unmeasurable
Breathing normal deepened, accelerated deepened, accelerated
Large fontanelle normal recessed markedly, deeply sunken
Skin tension
good reduced When the skin eyelashes are formed, they stand
Eyes normal with tears sunken, tears may be in small amounts sunken, dry, tears absent
Mucous membranes moist dry, dry lips very dry, cracked lips, tongue
Urination normal reduced urination, darker urine,
urine smells
little urine, urination may disappear
Capillary return normal within 2 seconds within 3 seconds over 3 seconds
Fluid deficit 30-50 ml/kg 60-90 ml/kg 100 ml/kg or more

Warning signs of dehydration in a nutshell

Refer to the table to get an idea of the severity of the symptoms. If you suspect dehydration based on the symptoms listed, it is necessary to replenish fluids. In the case of moderate to severe dehydration, immediate professional help should be sought.

Professional help should also be sought if you cannot replenish fluids at home, if the child refuses fluids or if vomiting or persistent diarrhoea persists.

Small child, infant - crying
Observe the baby's overall expression, skin, tears during crying and fontanelle. Photo source: Getty Images

Warning signs to seek professional help include:

  • Dry skin, lips, tongue, decreased saliva production
  • crying without tears
  • the child is irritable or tired, sleepy (out of mode), laying his/her head
  • sad mood, uninterested in play
  • disorientation is associated
  • dark, yellow-orange smelling urine
  • cessation of urine production if children do not urinate for 3-4 hours by six months
    • in older children for more than 6-8 hours
  • in infants, a sunken fontanelle
  • sunken eyes
  • flaccid muscles, limbs
  • distended but also painful abdomen
  • feeling like vomiting
  • weight loss
  • dizziness
  • collapse
  • impaired consciousness, unconsciousness
  • deepened, rapid and irregular breathing
  • rapid pulse

Let's look at all the summer problems together:
Our health in summer - sun, heat, injuries and illness

The dangers of dehydration in children

The risk of dehydration is higher in children, not least because the metabolism of the child's body is faster. Its compensatory mechanisms and reserves are smaller than those of an adult.

In children, dehydration develops quickly, and within a few hours!

Complications of severe dehydration include acute renal failure (acute renal insufficiency). The child's body is exhausted by accelerated cardiac work. Irregular breathing is a threat. Body convulsions, disturbances of consciousness and even unconsciousness (coma) are dangerous. Hypovolemic shock develops. If the problem persists, death is a threat.

Treatment of dehydration in children

As in the treatment of dehydration in adults, it is most important to replenish the missing fluids. With mild dehydration, mineral unsweetened water or tea sweetened with grape sugar can be used.

Fluids are given by the spoonful, cold, and one teaspoon every 10-15 minutes. If the child tolerates this, it is continued at a higher frequency, every 5-10 minutes, up to 120 milliliters per hour.

If the child is vomiting or has diarrhoea, it is important that fluids are given in the above manner. Treatment for this condition is also needed to avoid complications. Administration of a rehydration solution is appropriate.

A rehydration solution will replenish lost fluids and also minerals that are lost with water during diarrhoea and vomiting. Solutions are available that can be applied from the 1st week of life.

In older children, fluids are given by the tablespoon and at regular intervals. Water, mineral water, rehydration solution should be alternated. Diluted fresh fruit or vegetable juices are also suitable.

In addition to fluid replenishment, a resting regime, a light diet and monitoring of health status are important. If the symptoms of dehydration worsen and treatment of the underlying cause does not help, a specialist examination is needed. This is to prevent the development of a more severe form of dehydration.

The smaller the child, the more difficult it is to manage dehydration in the home environment.

Prevention of dehydration in children is most important

Prevention should be the first priority. Parents should be informed what to do if the child's health deteriorates. This is especially the case with diarrhoea, vomiting and fever. Of course, it is important to think about replacing lost fluids and drinking adequately.

During hot summer days, and especially during increased physical activity, it is important to replenish fluids regularly. Also during windy days and even during cold, dry weather. This is when fluid loss occurs at an increased rate.

Boy drinking water from bottle, green grass in background
The habit of proper drinking is important. Source: Getty Images

Parents need to encourage children to drink regularly and to motivate them positively when they refuse to drink. A suitable way is to use coloured glasses with pictures and to join in drinking with them.

Children enjoy clinking their glasses, although some might argue that this fosters an addiction to alcohol. Alternatively, it is a good idea to find other appropriate but playful ways to encourage the child to drink fluids.

Table water, low mineralised water, fresh fruit and vegetable juices, fruit teas are suitable. On the other hand, sweetened drinks, highly carbonated bottled water, energy drinks, black tea or coffee and alcohol are not suitable for children.

Even diet can help to replace lost fluids. For example, choosing the right fruit and vegetables can help. These include cucumber, tomato, lettuce, apple, nectarine and others. The biggest source of water from vegetables is, of course, watermelon.


When to increase fluid intake:

  • When fever is present
  • increased fluid loss due to diarrhoea, vomiting, increased urination
  • burns and scalds
  • blood loss
  • increased sweating, hot weather
  • during dry weather
  • increased physical exertion

And what to supplement with:

  • pure water
  • for young children, infant formula
  • mineral water
  • rehydration solution
  • tea
  • fresh fruit juices
  • milk
  • light diet
  • fruit, vegetables


  • Thirst
  • dry skin, mucous membranes
  • reduced skin elasticity (turgor)
  • reduced urine output
  • headache
  • weight loss of more than 3% of body weight
  • fatigue
  • loss of interest in the game
  • sleepiness
  • rapid pulse
  • cold and blue acral, i.e. terminal parts of the body
  • confusion
  • collapse
  • cessation of urination
  • disturbances of consciousness, unconsciousness
  • respiratory disturbances

Inappropriate are:

  • sweetened beverages
  • energy drinks
  • carbonated bottled water
  • coffee
  • black tea
  • alcohol

Video about dehydration

fshare on Facebook

Interesting resources

The aim of the portal and content is not to replace professional examination. The content is for informational and non-binding purposes only, not advisory. In case of health problems, we recommend seeking professional help, visiting or contacting a doctor or pharmacist.