Signs of serious illness in children factsheet


As a parent you know what your child is like when they are well so you can detect the subtle changes in mood, behaviour and appetite that indicate your child may be developing an illness.

If there are signs that your child is only slightly unwell, you may choose to wait to see how the illness progresses before seeing a doctor.

If you are worried about your child, your family doctor should be the first point of contact.

 Things to consider


If your child is having difficulty breathing or breathing loudly, you should see a doctor urgently. If the problem is very severe, your child’s lips may be purple or there may be pauses when they are breathing. You should call an ambulance if this occurs. 

Skin colour and appearance

If your child has unusual paleness or a purple colouring of skin, you should see a doctor.

Many rashes are due to minor infections and are not serious. If your child has a purple rash that does not fade, you should see a doctor urgently. This may be a sign of meningococcal infection.

Fluids in and out

If your child is drinking less than half the normal amount or not passing some urine every 6 hours you should see a doctor to check if they are becoming dehydrated. Signs of serious problems include

  • vomiting with blood or green fluid 
  • blood in their wee or stools. 

You should see a doctor urgently if these occur.

Other signs of potentially serious problems include severe or persistent pain or distress, rash and seizures (fits).


Fever itself is not harmful. A fever needs rest and fluids, but sometimes it is bacterial and needs treatment with antibiotics.

A baby under 3 months with a fever over 38°C should be taken to see a doctor. 

Use the symptoms described below (changes in alertness, breathing, skin colour) to determine how sick a child with a fever is. If your child shivers with the fever you should see a doctor.

Seizures (fits)

If your child has a seizure, lie the child on their side and call an ambulance. 


See a doctor more urgently if your child is experiencing these symptoms:

  • irritability
  • breathing difficulty 
  • skin colour and appearance
  • fluids in and out - how much your child is drinking and passing urine. 

As your child becomes unwell they may become less active, sleep more and become more drowsy. More serious abnormalities are floppiness, a weak cry, irritability or poor response to things around them – see a doctor urgently if these occur.

Last updated Thursday 21st March 2024


This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.

© Sydney Children’s Hospitals Network 2024