Dehydration in Children
Informed by recognized medical guidance
If symptoms are severe, worsening, or life-threatening, seek urgent medical care now.
Overview
Dehydration happens when a child loses more fluids than they take in. Their body does not have enough water and minerals (called electrolytes) to work properly. This can happen quickly, especially in small children.
Key facts
- Children get dehydrated more easily than adults because their bodies are smaller and lose fluids faster.
- Mild dehydration is common and can often be treated at home with extra fluids.
- Severe dehydration is a medical emergency and needs prompt care.
- Signs include a dry mouth, sunken eyes, fewer wet nappies, and irritability.
Yes, dehydration is very common in children, especially during illnesses like stomach bugs, with vomiting and diarrhoea, or in hot weather.
Infants and young children are at highest risk because they have a smaller body size and lose fluids more quickly. Babies under 6 months are especially vulnerable.
Symptoms
- Difficulty breathing or rapid breathing
- Seizures (convulsions)
- Unconsciousness or passing out
- Very dry mouth and sunken eyes
- No urine for 8 to 12 hours
- Extreme lethargy – the child is very hard to wake or seems limp
- ⚠The child has been vomiting or has diarrhoea for more than 6 hours
- ⚠Signs of dehydration that do not improve after trying home fluids for a few hours
- ⚠A baby under 3 months with any sign of dehydration
Common symptoms
- Dry mouth and lips
- Fewer wet nappies or less frequent urination
- Dark yellow urine
- Thirst
- Irritability or fussiness
- Tiredness or low energy
Symptoms in children
- Crying without tears
- Sunken fontanelle (soft spot on the top of a baby's head)
- No wet nappy for 6 hours or more
- Cold hands and feet
- Drowsiness or being very sleepy
- Being unusually quiet or hard to wake
Causes
Main causes
- Not drinking enough fluids (especially during illness or when feeling unwell)
- Vomiting and diarrhoea from stomach bugs (gastroenteritis)
- Fever that makes the body lose more water through sweat
- Hot weather or too much time in the sun without enough to drink
Risk factors
- Being a baby under 6 months old
- Having a chronic illness like diabetes or kidney problems
- Having a high fever
- Prolonged vomiting or diarrhoea (more than 24 hours)
- Not breastfeeding or bottle-feeding enough
- Living in a hot climate or during heatwaves
When to see a doctor
See a doctor urgently if:
- Call emergency services if the child has any emergency symptoms (see above).
- See a doctor urgently if the child has signs of moderate dehydration: sunken eyes, no tears when crying, a dry mouth, less than half the usual amount of urine, or seems unusually tired or fussy.
Book a routine appointment if:
- Make a routine appointment if mild dehydration (a dry mouth, slightly less urine) does not improve after a day of home care.
- Talk to your doctor if you are worried about your child's feeding or drinking.
Diagnosis
A doctor will examine your child and ask about recent symptoms, fluid intake, and how much they urinated. They may check the child's weight and compare it to a previous weight to see how much fluid has been lost.
Tests that may be done
- A urine test to see if the urine is too concentrated
- Blood tests to check the level of electrolytes (like sodium and potassium) in severe cases
- Checking skin elasticity (how fast skin goes back after being pinched)
- Checking heart rate and blood pressure
What to expect at your appointment
The doctor will likely ask about vomiting, diarrhoea, fever, and how much the child has been drinking. They may weigh the child and examine their mouth, eyes, and skin. In mild cases, no tests are needed. In more serious cases, a small blood sample may be taken.
Treatment
Treatment focuses on putting back the fluids and minerals (electrolytes) that the child has lost. For mild dehydration, this can be done at home with oral rehydration solution. For moderate to severe dehydration, medical care is needed.
Self-care at home
- Give an oral rehydration solution (ORS) in small, frequent sips. You can buy ORS at a pharmacy. Follow the instructions on the packet.
- If the child is breastfed, continue breastfeeding often. For formula-fed babies, give usual formula as well as ORS.
- Offer clear fluids like water or very diluted fruit juice (for older children). Avoid sports drinks, soda, or undiluted juice.
- Do not stop giving fluids if the child vomits – wait 10 to 15 minutes and try again with smaller sips.
- Rest is important. Keep the child cool and comfortable.
Medical treatments
In a hospital, a child with moderate to severe dehydration may receive fluids directly into a vein (intravenous fluids). Doctors will also monitor the child's electrolytes and may give extra minerals if needed. No specific medications are recommended without a doctor's approval.
When is surgery considered?
Surgery is not needed for dehydration.
Living with this condition
After a bout of dehydration, help the child return to their normal diet and fluids gradually. Offer small, frequent feeds. Watch for any return of symptoms, especially if the underlying illness (like a stomach bug) continues.
Lifestyle tips
- Encourage your child to drink enough fluids every day, especially when they are active or in hot weather.
- Keep oral rehydration solution at home in case of illness.
- Make sure babies have regular feeds and older children have easy access to water.
Diet and exercise
Offer a balanced diet with plenty of fruits and vegetables, which contain water. During hot weather or exercise, give extra water. Avoid strenuous exercise in extreme heat.
Mental health and emotional wellbeing
Dehydration can make children irritable and fussy, but this usually improves quickly once they are rehydrated. Stay calm and offer comfort. If you feel stressed, speak to a healthcare professional for support.
Prevention
Yes, dehydration can often be prevented by making sure children drink enough fluids throughout the day, especially when they are ill, have a fever, or during hot weather. Offer fluids before they feel thirsty. For babies, ensure regular breastfeeding or bottle-feeding.
Complications
If left untreated
- Kidney problems (acute kidney injury)
- Seizures due to electrolyte imbalances
- Shock (a severe drop in blood pressure that can be life-threatening)
- Heatstroke in hot weather
Long-term outlook
Most children recover fully from dehydration with proper care. The outcome is excellent when treatment is given early. Even severe dehydration is highly treatable in a hospital setting, and most children return to normal within a few days.
Find support
International organisations
Local organisations
- NHS (UK) ↗ · United Kingdom
- Healthychildren.org (American Academy of Pediatrics) ↗ · United States
Helplines
External links open third-party websites. Ruqelo Health is not responsible for external content. Listing an organisation does not imply endorsement.
Always verify with your doctor
Health guidelines vary by country and region. The information in this article is based on international clinical guidelines but may not reflect the specific guidelines, medications, or practices in your country. Always discuss your health concerns with your own doctor or healthcare provider, and refer to your local national health guidelines where available.
Important notice This information is for educational purposes only. It does not replace professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider about your specific situation. If you are experiencing a medical emergency, call your local emergency services immediately.
Related conditions
Sources and guidance
This article is educational and is prepared with reference to recognized health information and clinical guidance sources where available. Specific source links may vary by topic.
Last updated: July 16, 2026
Educational note: This information is for education only and is not a diagnosis.
Use it to support, not replace, advice from a licensed clinician.
If symptoms are severe, worsening, or urgent, call your local emergency number or seek emergency care.
Guidance may differ by country or region. Confirm local recommendations with a qualified healthcare provider.