Recognition of serious illness in children

Disclaimer: This fact sheet is for education purposes only. Please consult with your doctor or other health professional to make sure this information is right for your child.

As a parent you know what your child is like when he is well so you can detect the subtle changes in mood, behaviour, activity and appetite that indicate your child may be developing an illness. If there are signs that your child is only very mildly unwell you may choose to wait to see how the illness progresses before seeing a doctor.  If you are worried about your child you should take him to see a doctor. Your family doctor should usually be the first doctor to contact.  If you feel your child needs to be seen urgently then your local Emergency Department is always available. 

When should I be concerned?

There are general features of a more serious illness which should prompt you to see a doctor more urgently. These include:

  • alertness and irritability
  • breathing
  • skin colour and appearance
  • fluids in and out - how much your child is drinking and passing urine
  • You should seek help urgently if these features develop rapidly, occur together or if your child is very young.


As your child becomes unwell he 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 him – see a doctor urgently if these occur.


If your child is breathing rapidly, noisily or seems to be having difficulty breathing you should see a doctor urgently. If the problem is very severe you may see a dusky colour around your child’s lips or there may be pauses when he stops breathing. You should call an ambulance if these occur.

Skin colour and appearance

If your child has unusual paleness or a purple mottling of the skin of the extremities 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 with pressure you should take him to a doctor urgently. Press a glass on the skin and look through it to see if it fades. This may be a sign of meningococcal infection. (See meningococcal fact sheet)

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 he is becoming dehydrated. Signs of serious problems are vomiting with blood or green fluid (bile), or bowel motions with blood. 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.  The infection causing the fever is often viral and needs rest and fluids, but sometimes it is bacterial and needs treatment with antibiotics. A baby under 3 months with a fever over 38o should be taken to see a doctor as the cause is often hard to find and the other signs of illness may be difficult to detect.

Use the features described above (changes in alertness, breathing, skin colour and fluids in and out) to determine how sick an older infant or child with a fever is. If your child shivers with the fever you should take him to see a doctor.

Seizures (fits)

If your child has a seizure you should lie him on his side and call an ambulance (see seizure fact sheet).


  • You know your child best.
  • If you are worried about your child you should taken him to see a doctor.
The Children's Hospital at Westmead
Sydney Children's Hospital, Randwick
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