About dehydration
Dehydration is a lack of water in your body. If your child loses a lot of body fluids or isn’t drinking enough, they might get dehydrated.
Gastroenteritis is the most common cause of dehydration. This is because it can make your child lose a lot of body fluids quickly. Any health condition that causes persistent diarrhoea, vomiting or reduced fluid intake can result in dehydration.
A lot of sweating can also result in dehydration. This can happen when babies experience very hot weather or children and teenagers do vigorous physical activity.
Symptoms of dehydration
Children with mild dehydration might not have symptoms.
Children with severe dehydration might:
- urinate less often
- lose weight
- look paler than usual
- feel weak, tired, lethargic or irritable
- have fewer tears
- be thirsty
- have a coated and dry tongue and mouth
- have sunken eyes and darkening around the eyes
- have cold hands and feet.
It can be hard to know whether younger children are urinating less often. The best way to tell is by checking their nappies. They might have lighter or fewer wet nappies than usual.
Medical help: when to get it for dehydrated children and teenagers
You should see your GP if your child is under 6 months and has vomiting or diarrhoea.
If your child is older than 6 months, you should take them to the GP if they:
- are urinating less often
- have been vomiting often, can’t keep any fluids down, or have been vomiting for more than 24 hours
- have diarrhoea lasting longer than 2 weeks
- aren’t gaining weight or are losing weight because of vomiting or diarrhoea.
Go to a hospital emergency department or call 000 for an ambulance straight away if your child seems very unwell or has symptoms of severe dehydration:
- no urine
- skin that’s paler than usual
- sunken eyes, cold hands and feet
- drowsiness or irritability.
You know your child best. If your child seems unwell, seek medical attention. Signs that your child has a serious illness that needs urgent medical attention include severe pain, drowsiness, skin that looks grey or paler than usual, dehydration, troubled breathing, seizures and reduced responsiveness.
Prevention and treatment of dehydration
The best way to prevent and treat dehydration is to make sure your child has enough fluids. How much fluid your child needs and how often they need it depends on your child’s age.
Our article on preventing and treating dehydration explains what to do and how much fluid to give when you’re concerned about dehydration in babies aged 0-6 months, babies aged 6-12 months, and children aged 12 months and older.