Dengue in children: warning signs, platelets and when to go to hospital

Dengue in children is usually a short viral fever that gets better at home with fluids and paracetamol. The risky time is often around the day the fever settles, and it is not simply about when the platelet count is lowest. Watch how your child looks, drinks and passes urine. Those tell you more than any single blood report.

What is dengue and how do children catch it?

Dengue is a virus infection spread to people by the bite of an infected mosquito, mainly the Aedes mosquito.¹ Children do not catch it from each other by playing or sharing food.

The Aedes mosquito bites mainly in the daytime.¹ It breeds in small pools of clean, still water. In Kolkata that means flower vases, desert cooler trays, plant saucers, old tyres, open water drums and the bucket left on the roof after the rain. This is why dengue cases climb in the monsoon and the weeks after it.

There are four types of dengue virus. Catching one type protects you for life against that type only.² A second infection with a different type carries a higher chance of severe illness.^1,2

What are the first symptoms of dengue in a child?

Most children have a sudden high fever with body ache, headache and poor appetite. Many have only a mild illness, and some have no symptoms at all.¹

Common signs in the first few days:^1,2

• High fever that comes on suddenly
• Headache and pain behind the eyes
• Aching muscles and joints
• Nausea and vomiting
• A red, flushed face or a rash

Babies and toddlers cannot tell you about headache or eye pain. They are simply cranky, hot, off their feeds and sleepier than usual. In the monsoon, Dr Dutta treats any high fever in a small child as possible dengue until tests show otherwise.

How many days does dengue fever last?

The fever usually lasts 2 to 7 days.^2,3 Most children then feel better and recover fully over a week or two.¹

Doctors think of dengue in three phases:^2,3

• Fever phase: about 2 to 7 days of high temperature and aches.
• Critical phase: starts around the time the fever comes down and usually lasts 24 to 48 hours.
• Recovery phase: the child perks up, appetite returns and the blood counts climb back.

Most children never have a real critical phase. They simply get better when the fever goes. Doctors cannot always tell in advance which child will, which is why we watch everyone closely at that point.²

Why is the day the fever goes away the most dangerous day?

Because in some children, this is when the blood vessels start to leak fluid. It feels like recovery, but it is the time to watch most closely.^2,3

In this critical phase, the liquid part of the blood (plasma) seeps out into the tummy, the chest and the tissues. The blood left behind becomes thicker. If enough fluid leaks out, blood pressure falls and the child can go into shock (when the body's organs do not get enough blood).²

The WHO notes that the signs of severe dengue often appear after the fever has gone.¹ So when the thermometer finally reads normal, please do not relax and send your child back to school. Keep the fluids going and keep watching for the warning signs below for the next two days.

What are the warning signs of severe dengue in children?

Tummy pain, repeated vomiting, bleeding, unusual sleepiness or restlessness, and cold, pale skin are the main warning signs. Any one of them means your child needs to be seen in hospital the same day.^1,3

Watch for:^1,2,3

• Pain or tenderness in the tummy
• Vomiting again and again, so fluids do not stay down
• Bleeding from the gums or nose, or blood in vomit or stools
• Black, tarry stools
• Being very drowsy, floppy or very restless
• A puffy face or a swollen tummy
• Fast breathing
• Cold, pale or clammy hands and feet

Dr Dutta also wants to know at once if your child is passing much less urine than usual.

A large review of 143 studies found that tummy pain, vomiting, lethargy and black stools were each linked with severe dengue. So were an enlarged liver and fluid in the tummy or chest, which doctors look for on examination or ultrasound.⁴

Are children more at risk of severe dengue than adults?

Yes. In a review of 143 studies, being a child roughly doubled the odds of severe dengue.⁴

The same review found higher risk with a second dengue infection, and in people with diabetes or kidney disease.⁴ Babies and toddlers also cannot tell you how they feel, so changes are easier to miss.

This does not mean most children get severe dengue. Most do not. It means a child with dengue deserves a daily check by a doctor in the early days, and parents who know the warning signs.

Why does the doctor care more about haematocrit than platelets?

Because a rising haematocrit shows the blood vessels are leaking, and leaking is what makes children dangerously ill. A falling platelet count on its own is expected in dengue.²

Haematocrit (also called PCV) is the share of the blood made up of red cells. When plasma leaks out, the red cells become more concentrated, and the haematocrit goes up. A rising haematocrit at the same time as a fast fall in platelets is one of the warning signs doctors look for.^2,4

Platelets (the tiny blood cells that help clotting) drop in most children with dengue and recover by themselves. Bleeding often does not match the platelet number. An Indian review notes that bleeding can even happen with a normal count.²

So a child at 40,000 who is drinking well and passing urine may be safer than a child at 1,00,000 who is cold and drowsy with a climbing haematocrit.

At what platelet count does a child need a platelet transfusion?

There is no single number. Giving platelets just because the count is low, when the child is not bleeding, is not recommended.²

The best trial on this was in adults. In 372 patients with dengue and platelet counts of 20,000 or less, giving platelets did not reduce bleeding. It did cause more side effects, such as allergic reactions and one case of fluid overload.⁵ A 2026 review of 9 studies found that preventive platelet transfusion did not speed up platelet recovery and was linked with more bleeding and deaths, though most of its studies were not randomised.⁶

A study from AIIMS, New Delhi, during the 2013 dengue epidemic found that about 23 percent of platelet transfusions given were not appropriate.² Platelets have a place when a child has serious bleeding. That decision belongs to the treating team, not to the platelet number alone.

Does papaya leaf juice increase platelets in dengue?

It may raise the platelet number a little, but there is no good proof that it prevents shock, bleeding or death.⁷

A review of nine studies, six of them from India, found that papaya leaf extract was linked with higher platelet counts and possibly a shorter hospital stay. The evidence was of low quality, and the authors said the evidence was not enough to say what role it has in treating dengue.⁷

My view: a raised platelet number is not the same as a safer child. If your family wants to use papaya leaf, tell your doctor. Never let it replace fluids, delay a hospital visit, or upset a child's stomach so much that they stop drinking.

What should my child drink when they have dengue?

Plenty of fluids, little and often, through the whole illness. Fluids are the main treatment, because there is no medicine that kills the dengue virus.^1,2

Good choices for an Indian home:

• ORS made exactly as the packet says
• Coconut water
• Nimbu pani with a pinch of salt
• Rice water, dal water, clear soups
• Buttermilk (chaas)
• Breast milk for babies, offered more often

Avoid cola and very sugary packaged drinks. If your child feels sick, give small sips every few minutes rather than a full glass at once. Write down when your child passes urine. A child who keeps passing pale urine through the day is usually getting enough. A child who is passing much less than usual needs to be seen.

Which medicine is safe for fever in dengue?

Paracetamol is the safe choice, in the dose your doctor gives for your child's weight. Ibuprofen, aspirin and similar painkillers should be avoided, because they can raise the risk of bleeding.^1,2

This group of medicines is called NSAIDs (non-steroidal anti-inflammatory drugs). In India they hide in many fever syrups and "body pain" tablets, often mixed with paracetamol. Mefenamic acid and diclofenac belong to the same group. Read the label, and ask the chemist if you are unsure. Dr Dutta also asks families to refuse the fever injection that some local clinics give, because you often do not know what is in it.

Paracetamol may bring the fever down by only a degree. That is fine. The aim is comfort, not a normal number. Never give more than the daily maximum your doctor tells you.

Which blood test confirms dengue in a child?

In the first week of fever, an NS1 antigen test (which finds a piece of the virus) is useful. After about day 3, an IgM antibody test picks up most recent infections.⁸

The US CDC advises using an NS1 test or a PCR test together with an IgM test in the first 7 days of illness. IgM can pick up most recent infections after day 3.⁸ A negative NS1 test does not rule dengue out.⁸ If your child looks like dengue in the middle of an outbreak, your doctor may treat it as dengue even with a negative test.

A complete blood count (CBC) is repeated to follow the platelets, white cells and haematocrit. How often depends on how your child is doing.

Can my child be treated for dengue at home?

Yes, most children with dengue can be looked after at home, if they are drinking well and have no warning signs.²

Home care means:^1,2

• Rest
• Plenty of fluids
• Paracetamol only, for fever and pain
• Knowing the warning signs and acting on them fast

Dr Dutta also likes to see the child, often daily, in the early days.

Children with warning signs, or who cannot drink enough, usually need a hospital bed. There, fluids can be given through a drip and carefully adjusted.² Dr Dutta also admits babies and children with other illnesses more readily. Too much drip fluid can also harm, especially in the recovery phase, which is why this is done in hospital and not at a local clinic.²

Can a child get dengue twice?

Yes. There are four types of dengue virus, and having one type protects only against that type.²

A second infection with a different type carries a higher risk of severe dengue.^1,4 So if your child had dengue before, tell the doctor at the next fever. It is one more reason to take mosquito control seriously at home, even after your child has "already had it".

How do I protect my child from mosquito bites?

Cover the skin, use nets and screens, and use a mosquito repellent as the label directs. Remember that the dengue mosquito bites in the day.¹

What the WHO suggests:¹

• Clothes that cover as much skin as possible: full sleeves and long trousers
• Mosquito nets, ideally treated with repellent, for daytime naps
• Screens on windows
• Repellents containing DEET, picaridin or IR3535

For young children, an adult should put the repellent on. Rub it on your own hands first and then on the child, keeping it off their hands, eyes and mouth. Follow the age limits printed on the product.

Most mosquito bites in children cause only an itchy red bump. A cold, wet cloth and calamine lotion help. Keep nails short so scratching does not break the skin and let in infection.

How can we stop mosquitoes breeding around our home?

Empty, scrub and cover anything that holds water, at least once a week.¹ Aedes eggs need only a little water to hatch.

A weekly round for the whole family:

• Change the water in vases and pet bowls
• Empty and dry desert cooler trays
• Turn over unused pots, buckets and tyres
• Cover water drums and overhead tanks with tight lids
• Clear the roof and balcony after rain

The WHO also lists proper rubbish disposal and covering stored water as key steps.¹ Ask your housing society to do the same in common areas. One open tank on the roof can feed the whole building.

Is there a dengue vaccine for children?

One dengue vaccine, called QDenga, is licensed in some countries. The WHO recommends it only for children aged 6 to 16 years in places with high dengue spread.¹

Other vaccines are still being tested.¹ An earlier vaccine raised the risk of severe dengue in people who had never had dengue before, so its use needed a blood test first.² Vaccine rules and availability in India keep changing. Ask your paediatrician what is available and suitable for your child at the time you read this.

When should I take my child with dengue to hospital?

Go to hospital straight away if your child has any of these:^1,2,3

• Tummy pain, or vomiting so often that fluids do not stay down
• Bleeding from the gums or nose, blood in vomit, or black stools
• Very drowsy, floppy, confused or very restless
• Cold, clammy or mottled hands and feet
• Fast or difficult breathing, or a swollen tummy or puffy face

Come in too if your child is passing very little urine, or if your child is a baby or has a long-term illness and you think it is dengue.

Pay special attention in the two days after the fever settles. Early care in hospital greatly lowers the risk of dying from severe dengue.¹