Dehydration in babies and children factsheet

Introduction

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 give them enough 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 age, your child will also be given small amounts of oral rehydration fluids regularly. Oral rehydration fluids are specially made to replace fluids and salts.

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 litres 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.

Dehydration in babies and children