Kids Health Info

Dehydration

  • Dehydration occurs when there isn’t enough fluid in the body to keep it working properly. The body needs water to help maintain body temperature, make bodily fluids and for day-to-day functioning.

    Young children and babies are at greater risk of becoming dehydrated than adults. Keeping your child hydrated is important at all times, but especially when they are unwell.

    If your child is very thirsty, they are probably already dehydrated. The effects of severe dehydration can be serious.

    Signs and symptoms of dehydration

    If your child is mildly dehydrated, they may have:

    • dizziness or light-headedness 
    • nausea or headaches 
    • dark yellow or brown urine (wee) – urine should be pale yellow 
    • fewer wet nappies or nappies not as wet as usual; or older children will not go to the toilet as much 
    • dry lips, tongue, mouth or throat.

    If your child has severe dehydration, they may be:

    • extremely thirsty
    • lethargic or less active than usual 
    • pale and have sunken eyes, tears may be absent when crying 
    • cold – especially their hands or feet 
    • breathing faster than usual and have a fast heart rate 
    • irritable, drowsy or confused.

    If your child shows signs of severe dehydration, see your GP or go to your closest hospital emergency department.

    Care at home for mild dehydration

    The best treatment for mild dehydration is to give your child more fluid to drink, such as water or oral rehydration solutions. Gastrolyte, HYDRAlyte, Pedialyte and Repalyte are different types of oral rehydration solutions (fluids) that can be used to replace fluids and body salts. These are the best option if your child is dehydrated, and can be purchased from your local pharmacy or supermarket. They are also available as icy poles, which children are often happy to have.

    If your child refuses water or oral rehydration fluids, try diluted apple juice. You can also give your child their usual milk. Do not give drinks that are high in sugar (e.g. flat lemonade or sports drinks), because they can make dehydration worse.

    Infants

    If your baby is under six months old, they should always be seen by a doctor if they are dehydrated. For babies over six months:

    • If you are breastfeeding your baby, continue to do this but feed more often. You can also give an oral rehydration solution or water for the first 12 hours.
    • If you are bottle feeding your baby, replace formula feeds with oral rehydration solution or water for the first 12 hours, then give normal formula in small, but more frequent amounts.

    Older children

    For older children (over 10 kg) who are dehydrated, give at least one cup (250 mL) of water (or oral rehydration solution) to drink, every hour for four hours. Give them more than this to drink if they are vomiting or have diarrhoea. Your child may want to drink it all at once or drink smaller sips frequently.

    Smaller children will need less to drink than older children.

    When to see a doctor

    Babies and young children are at greater risk of becoming dehydrated. If your child is under six months of age or has a chronic (long-term) illness, see your GP if you think your child is dehydrated.

    If your child shows signs of severe dehydration or you are concerned for any reason, see your GP or go to your closest hospital emergency department.

    If your child is unwell, they may need medical treatment to help replace lost fluids. This can involve using a feeding tube that goes into the stomach via the nose, or fluids given directly into a vein through a drip (intravenous or IV therapy).

    What causes dehydration?

    Children are more likely to become dehydrated:

    • after lots of physical activity or exercise
    • with severe vomiting or diarrhoea
    • if they have a fever
    • if they take certain medications, such as diuretics
    • if they don’t drink enough, especially during times of illness
    • if they are younger than six months of age
    • in hot weather.

    Making sure your child drinks enough water each day can help prevent dehydration. Providing extra drinks of water in hot weather, during and after exercise and during illness is particularly important.

    Key points to remember

    • Young children and babies are at most risk of becoming dehydrated.
    • If your child is very thirsty, they are probably already dehydrated.
    • Mild dehydration can be treated at home by giving oral rehydration fluids or water. Do not give drinks that are high in sugar.
    • If your child show signs of severe dehydration, see your GP or go to your closest hospital emergency department.

    For more information

    Common questions our doctors are asked

    Should my child drink sports drinks when playing sports to prevent dehydration?    

    Sports drinks are not recommended for hydration, as there is often a high sugar content. Drinks that are high in sugar can make dehydration worse. During sports, children can drink water or oral rehydration solutions. 

    What illnesses are most likely to cause dehydration?      

    Gastroenteritis is the most common cause of dehydration, because the body loses fluids through the vomiting and diarrhoea, and oral intake is usually reduced. Illnesses where children have a sore throat or sore mouth (e.g. tonsillitis or hand, foot and mouth disease) can lead to dehydration if the pain is making your child reluctant to eat or drink. Having a high fever is also linked with dehydration, because your child is losing fluids through sweating.


    Developed by The Royal Children's Hospital Community Information and Anaesthesia and Pain Management departments. We acknowledge the input of RCH consumers and carers. 

    Reviewed August 2018. 

    Kids Health Info is supported by The Royal Children’s Hospital Foundation. To donate, visit www.rchfoundation.org.au

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Disclaimer
This information is intended to support, not replace, discussion with your doctor or healthcare professionals. The authors of these consumer health information handouts have made a considerable effort to ensure the information is accurate, up to date and easy to understand. The Royal Children's Hospital, Melbourne accepts no responsibility for any inaccuracies, information perceived as misleading, or the success of any treatment regimen detailed in these handouts. Information contained in the handouts is updated regularly and therefore you should always check you are referring to the most recent version of the handout. The onus is on you, the user, to ensure that you have downloaded the most up-to-date version of a consumer health information handout.