Dehydration in babies and children factsheet
Introduction
Dehydration is when a child loses fluid, like water, from their body faster than it can be replaced.
Dehydration happens when a child loses fluids from their body, like water, faster than they can be replaced through drinking or eating.
Dehydration can be caused by:
- vomiting
- diarrhoea - loose, watery poo that is hard to control
- heat stroke - when the body gets too hot for too long
- medications that remove fluid from the body, like diuretics
- not drinking enough fluid, especially when unwell
- fever
- physical activity and exercise
- hot weather.
Fluids are very important to keep your body working well. They have an important role in:
- regulating body temperature
- moving nutrients around the body
- flushing out waste
- making sure organs and tissue work properly.
Children are at higher risk of dehydration because they:
- lose more fluid through their skin
- usually do more physical activity during the day than adults
- are more likely to get viruses that cause vomiting and diarrhoea
- can’t always communicate that they are thirsty
- depend on adults to provide adequate fluids.
Signs and symptoms
Symptoms of dehydration can be mild or severe, depending on the cause.
Mild dehydration can cause:
- dizziness or feeling light-headed
- nausea or feeling sick
- a dry mouth, tongue, lips, or throat
- dark yellow or brown urine
- fewer wet nappies or visits to the toilet than usual.
Severe dehydration can be life-threatening and is considered a medical emergency. It can cause:
- extreme thirst
- pale skin
- sunken eyes
- no tears when crying
- cold hands and feet
- faster breathing and heart rate
- lack of energy
- irritability and confusion
- electrolyte imbalance – the loss of important salts and minerals from the body.
Severely dehydrated babies may also have a sunken fontanelle or soft spot on top of the head.
If your child shows signs of severe dehydration, call triple zero (000) for an ambulance or go to your nearest emergency department.
Diagnosis
Your child’s doctor can diagnose dehydration based on their symptoms.
They may also test a sample of your child’s wee to check the level of dehydration.
Treatment
Treatment for dehydration will depend on:
- how old your child is
- how severe their symptoms are
- any other health conditions they have
- what has caused the dehydration.
Babies under six months old who are dehydrated need medical treatment. See your local doctor or go to your nearest emergency department as soon as possible.
Fluids
Treatment for mild to moderate dehydration is focused on replacing fluids and managing your child's symptoms.
You should encourage your child to drink fluids, even if they are vomiting. Depending on your child’s age, this may include:
- water
- oral rehydration fluids
- breastmilk
- infant formula.
Some children may be able to take medication that can stop vomiting, but medication to stop diarrhoea is not recommended.
Speak to your local doctor or pharmacist for more information.
Oral rehydration fluids
Oral rehydration fluids are available from your local pharmacy or supermarket.
They are specially made to replace:
- fluids
- carbohydrates
- electrolytes like sodium and potassium.
Oral rehydration fluids can come in different flavours and forms, including:
- sachets or concentrated liquid to mix with water
- tablets to dissolve in water
- ice-blocks
- ready to drink bottles.
Follow the instructions on the package closely to ensure your child gets the right amount of fluids.
If you don’t have oral rehydration fluids at home, you can use things like apple juice. When using fluids like juice, make sure they are watered down.
Avoid fluids that are fizzy or high in sugar or soft drinks, as these can make dehydration worse.
Amount of fluids
Babies and children who are dehydrated may not want to drink. They may feel unwell, or they may vomit soon after drinking.
Try to give your child at least 5 mL of fluid per kg of body weight every hour.
For example:
- babies under 10kg - 60mL, given in 5ml doses every 5 minutes
- toddlers 10 - 20kg - 90mL, given in 7.5mL doses every 5 minutes
- primary school-aged children around 20kg - around 120mL every hour
- older children, over 30kg – around 180mL every hour.
Remember to be patient when giving fluids to your child. Offer small sips more often and, if possible, encourage them to sip after vomiting.
Babies and toddlers who are still breastfeeding can continue to be offered feeds. They may need to have fluids given with a medicine syringe, but older children may be able to sip on their own.
If your child can keep fluids down, slowly increase the amount they sip and reduce the frequency.
Fluids for babies and children over six months
Babies over six months who have gastroenteritis can have small amounts of water or oral rehydration fluids along with their breast milk or infant formula.
Do not add water to breast milk.
Do not add more water than needed to infant formula.
If your baby is breastfeeding, you should:
- continue breastfeeding or offering expressed milk on demand or at least every 2 hours
- offer water or oral rehydration solution with a syringe in between breastfeeds
- not give them solids while they are vomiting.
When the vomiting has stopped or after 24 hours, you can:
- continue to breastfeed or offer expressed milk on demand or every 2-3 hours
- offer water or oral rehydration solution with a syringe in between feeds
- re-introduce simple foods like rice cereal or vegetable puree slowly.
If your baby is formula-fed, you should:
- replace formula with oral rehydration fluids for the first 12 hours
- resume normal infant formula after 12 hours in smaller, more frequent amounts
- continue feeding every 2-3 hours or on demand
- re-introduce simple foods like rice cereal or vegetable puree slowly.
Severe dehydration
Severe dehydration can be life-threatening and is a medical emergency.
It is treated in the hospital with fluids given through a thin tube in the vein called an intravenous (IV) cannula.
Depending on their age, your child will also be given small amounts of oral rehydration fluids regularly.
Management
Daily fluids
Recommended daily amounts of fluids will depend on your child’s:
- age
- weight
- environment
- level of activity
- general health and any medications.
The below is a guide only.
Babies 0-6 months
- breastmilk and/or infant formula only
- no water or dairy milk
- feeding on demand or following medical advice.
Infants 6-12 months
- breastmilk and/or infant formula
- small amounts of boiled, cooled water
- no dairy milk
- feeding on demand or following medical advice.
Toddlers 1-3 years
- around 4 cups or 1 litre of fluids
- mainly water and breastmilk if still breastfeeding
- no more than 500ml of dairy milk in 24 hours to prevent nutritional deficiencies.
Children 4-8 years
- around 5 cups or 1.2 litres of fluid
- mainly water.
Pre-teens 9-13 years
- around 5-6 cups or 1.4- 1.6 litres of fluid
- mainly water.
Teenagers 13+
- around 6-8 cups or 1.6- 1.9 litre of fluid
- mainly water.
Keeping your child hydrated
Water should always be the first choice of fluids for children. Encourage your child to drink water regularly by keeping a water bottle nearby and filling it regularly throughout the day.
Try to avoid having drinks that can affect physical and dental health regularly, like:
- soft drinks – regular and sugar-free
- fizzy flavoured water– regular and sugar-free
- concentrated juice or cordial
- coffee
- energy drinks– regular and sugar-free
- sports drinks, unless playing sport - regular and sugar-free.
For high-intensity sports or exercise in hot environments, a low-sugar sports drink or electrolyte drink can be used alongside chilled water.
Plain dairy milk is also suitable for children over 12 months old as long as it is not used in place of meals or water throughout the day.
When to seek help
See your local doctor or go to the nearest emergency department if your child:
- has diarrhoea lasting more than a few days
- has been vomiting for more than 24 hours
- can’t keep any fluids down
- vomits blood or has bloody diarrhoea
- has not been willing to drink anything for several hours
- has not needed to urinate in the past 6 to 8 hours
- hasn’t had a wet nappy for 4 to 6 hours.