Here is the most important thing first: the dangerous phase of dengue is not when the fever is at its highest, it is WHEN THE FEVER BREAKS — usually between day 3 and day 7 of the illness. It runs against instinct: the family sees the temperature come down, feels reassured and watches less closely, at exactly the point when the closest watching is needed.
Recognising it, and what is very easily mistaken
The illness starts abruptly, not gradually like a cold: high fever, bad headache, pain behind the eyes, aching body and joints, nausea or vomiting, and possibly a red rash after a few days. The person feels completely wrung out.
The easiest confusion is with influenza and ordinary viral fevers. The reliable distinguishing feature is the COURSE: influenza is at its worst while the fever is up and then eases off; dengue can turn severe just as the temperature returns to normal. Nobody can tell them apart reliably by eye, so a blood test is needed.
Three phases, and the window to watch
| Phase | Usually | What the family does |
|---|---|---|
| Febrile | Day 1 to day 3 | Fluids, safe fever control, see a doctor for a blood test |
| Critical | Day 3 to day 7, begins WHEN THE FEVER BREAKS | Watch most closely, stay with the patient; any warning sign means hospital |
| Recovery | After day 7 | Return to normal eating gradually, keep watching for a few more days |
What to do at home straight away
- Write down on paper THE FIRST DAY of fever — this marker decides which day of the illness today is, and it is very often misremembered; every time you take a temperature, note the time alongside it.
- Give fluids steadily, a little at a time so they stay down: water that has been boiled and cooled, ORS mixed exactly as the packaging instructs, thin rice congee water, coconut water, milk.
- Watch the things you can observe: are they still able to drink, are they vomiting everything back up, are they passing urine, are they alert or dull.
- Let them rest, dress them lightly, sponge them with warm water when the fever is high.
- When the fever breaks, INCREASE the watching rather than reduce it, especially overnight. Assign one person to be on watch — do not let everyone assume somebody else is keeping an eye on things.
- Have the person with fever sleep under a mosquito net, during the day as well — a mosquito biting the sick person and then a well one is how the illness spreads within a household.
What you must NOT do
- Do NOT use ibuprofen, aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs) — this group increases the risk of bleeding. Many over-the-counter cold remedies contain them, so read the label or ask a pharmacist.
- Paracetamol is the usual choice for bringing a fever down, but the dose and the interval between doses are decided by a doctor or pharmacist — do not increase it yourself.
- Do NOT give an intravenous drip at home. A drip in dengue must be prescribed and monitored by a doctor; the wrong timing or the wrong volume both do harm.
- Do NOT take antibiotics on your own: this is a viral illness and antibiotics have no effect.
- Do NOT use coining, cupping or pricking the skin to let blood — these Vietnamese folk treatments cause bleeding and infection in someone who is already prone to bleeding.
- Do NOT wait overnight to see how things go once a warning sign has appeared, and do not believe that the fever breaking means it is over.
No specific medicine — watching IS the treatment
According to CDC, there is currently no specific antiviral medicine for dengue. Care consists of fluids, rest, safe fever control and catching the severe signs early. It sounds like little, but most critical cases are cases where the warning signs were missed in the first few hours.
When you need to go in
GO TO EMERGENCY CARE NOW — do not wait for morning, do not wait to see more — if the patient has ANY of the following: severe or steadily worsening abdominal pain; persistent vomiting, unable to keep fluids down; bleeding gums or nosebleeds; black stools or vomiting blood; restlessness, agitation, or lethargy and hard to rouse; cold, clammy, pale skin; no urine for hours. These signs often appear exactly as the fever breaks. Call 115 (the emergency number in Vietnam) or go to the nearest medical facility, and bring the notes with the dates of the fever.
| Level | Situation |
|---|---|
| Go to emergency care now | Any warning sign above; drowsiness, difficulty breathing, cold hands and feet, unable to drink anything |
| See a doctor within 24 hours | The fever has just broken but they are more tired than before; vomiting a lot, drinking little; third day of fever with no blood test yet |
| See a doctor within 24 to 72 hours | Fever has just started, still eating and drinking, alert — but a test is needed to know whether this is in fact dengue |
| Be more cautious than the levels above | Young children, older people, pregnant women, people with chronic illness, anyone who has had it before |
Prevention: the mosquitoes that carry it bite in the daytime
Contrary to the familiar picture, the mosquitoes that transmit dengue are most active during the day, most clearly in the early morning and late afternoon — so daytime mosquito protection matters just as much as at night. In Vietnam the illness circulates all year round, rising in the rainy season and in the weeks immediately after rain.
- Empty, turn over and change the water in every place it collects around the house: flower vases, plant pots, refrigerator drip trays, water jars, buckets, old tyres.
- Fit mosquito screens, use repellent cream or spray during the day as well; dress children in long sleeves when they go out into the yard.
- If someone in the house or the neighbourhood has already caught it, be stricter about clearing standing water for several weeks afterwards.
When to call a doctor to the house
Families usually need someone qualified for two things: a blood test to know whether this really is dengue, and someone who knows how to read the severe signs during the days that have to be watched. A doctor or nurse coming to your home can do both. But if any of the warning signs above have already appeared, go to hospital first and call afterwards — do not wait.
The day markers, warning signs and the advice to avoid ibuprofen and aspirin in this article follow the guidance of the US CDC; this article passes that on and does not replace being examined in person. Citing CDC here does not imply that CDC endorses Y Te Xanh or our services.
Need personalised advice for your loved one? Call our hotline 094 368 81 15 (24/7) — calling to ask a question or to book costs nothing. GreenCare has doctors who come to examine, nurses who carry out doctor's orders (injections, infusions, dressing changes), remote consultation by video call, and a review of the medicines you are taking; an in-depth remote consultation, or any one after the first, is a paid service. For children we take examination and acute care only — not long-term care at home, and not newborns or expectant mothers. We confirm we have staff in your area and provide transparent pricing before we begin.
Sources
- CDC — About Dengue
