Q: My child has had a 40°C fever for 3 days. How long does it last, and should I give medicine at 37.9°C before sleep?
- Myeongchan Kim
- 16 hours ago
- 2 min read
Medically reviewed by Sang Hyun Ahn, MD
Content edited by Myeongchan Kim, MD
This post is a dramatization of a question and answer session experienced by our actual medical reviewers. Please note that this content is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
Question:
My child has been running a fever for three days, and it has gone up to 40°C. How long does a fever usually last with a cold? The fever just won't break. Right now, the temperature is 37.9°C. Is it okay to give a fever reducer before putting my child to bed?
Answer:
It is completely understandable to be very worried when your child has a fever reaching 40°C for three days. Here is some guidance to help you manage the situation.
Duration of a Fever from a Cold
Most viral fevers typically last about 3 to 5 days.
However, if a high fever persists for more than 3 days, it is necessary to consult a doctor to check for a possible bacterial infection.
A temperature of 40°C is quite high, so careful observation is strongly advised.
Fever Reducer at 37.9°C Before Bed
Currently, 37.9°C is considered a mild fever.
If your child appears comfortable: You can let them sleep without administering a fever reducer.
If your child is uncomfortable or usually spikes a fever at night: You may give a fever reducer preventively before bedtime to help them sleep comfortably.
Safety check: Always verify the time of the last dose to ensure you are maintaining the proper 4 to 6-hour interval between medications.
⚠️ Go to the Emergency Room Immediately If:
Your child experiences difficulty breathing or decreased consciousness.
There are signs of severe dehydration (e.g., no urination for 8 hours or more).
The high fever is accompanied by a new skin rash.
Actionable Guidance:
Providing plenty of fluids to prevent dehydration is the most important thing you can do right now. Continue to monitor your child's condition closely overnight. If there is no significant improvement by tomorrow morning, please visit your pediatrician for an in-person evaluation to determine the exact cause of the prolonged fever.
For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.
