Chickenpox in Children: Symptoms, Vaccine and Home Care (SG)

Chickenpox is a very contagious viral infection that causes an itchy rash of spots that turn into blisters and then scabs, often with a fever and tiredness. In healthy children it is usually mild and clears up in one to two weeks. Your child is infectious from a day or two before the rash appears until every blister has dried and crusted over, so they should stay home from childcare or school until then. Singapore’s National Childhood Immunisation Schedule includes two doses of chickenpox (varicella) vaccine, at 12 and 15 months.

Here’s how to recognise it, ease the itch, which medicines to avoid, and the warning signs to act on.

What causes chickenpox?

Chickenpox is caused by the varicella-zoster virus. It spreads mainly through the air when an infected person coughs or sneezes, and also through contact with fluid from the blisters or with contaminated surfaces. It spreads very easily within families and in infant care and preschool classes.

According to Singapore’s Communicable Diseases Agency (CDA), symptoms usually appear 14 to 16 days after exposure, though the incubation period can range from 10 to 21 days. That is why a second wave in a class can follow a couple of weeks later.

Chickenpox symptoms in children

Some children feel unwell for a day or so before the rash: a mild fever, tiredness, a poor appetite or a headache. Then the rash appears, often first on the chest, back, face or scalp, before spreading.

• Red spots that appear in crops over several days
• Fluid-filled blisters that form on the spots and are very itchy
• Scabs as the blisters dry and crust over
• Spots can appear inside the mouth, on the eyelids and in the nappy area
• Fever, tiredness and grumpiness, especially in the first few days

A tell-tale feature is that spots, blisters and scabs are all present at the same time, because new crops keep coming for a few days.

Not every rash with fever is chickenpox. Small blisters on the hands, feet and mouth may point to hand, foot and mouth disease, while a pink rash that appears only after a high fever settles is more typical of roseola. Our guide to measles in children covers another rash illness to rule out. If unsure, see a doctor, and tell the clinic you suspect chickenpox before you arrive.

How long is chickenpox contagious?

HealthHub describes the infectious period as starting one or two days before the rash appears and lasting until the spots have stopped forming and have dried, which is usually about five to seven days after the rash starts.

While your child is infectious, keep them away from newborns, pregnant women who are not immune and anyone with a weakened immune system. If a pregnant family member or visitor has been in contact with your child, she should call her doctor promptly, as chickenpox in pregnancy can cause serious problems.

Home care: easing the itch and fever

There is no cure for uncomplicated chickenpox in healthy children. Treatment is about keeping your child comfortable, hydrated and from scratching the blisters open.

• Fluids first. Offer frequent drinks of water, milk or breast milk. If there are spots in the mouth, cold, soft foods are easier to manage.
• Cool, light clothing. Heat and sweat make the itch worse, which matters in Singapore’s humidity. Dress your child in loose cotton and keep the room cool with a fan or aircon.
• Calamine lotion and oatmeal baths are suggested by CDA and the American Academy of Pediatrics (AAP) for symptom relief. A short, lukewarm bath followed by patting the skin dry can also help.
• Short nails. Trim your child’s nails, and use cotton mittens on a baby at night. Scratching can cause infection and scarring.
• Ask about antihistamines. If the itch stops your child sleeping, your doctor or pharmacist can advise whether an antihistamine suits your child’s age.

Medicines: what to use and what to avoid

Paracetamol can ease fever and discomfort. Follow the label or your doctor’s or pharmacist’s advice for your child’s age and weight. Our baby fever guide has more on managing temperatures.

Antiviral medicine is sometimes prescribed, usually for adults, teenagers and children with weakened immunity or a higher risk of complications. HealthHub notes it is most effective when started within the first 24 hours of the rash, so see your doctor early if your child falls into a higher-risk group.

Red flags: when to see a doctor urgently

Most children recover without problems, but complications do happen. CDA lists bacterial skin infections, pneumonia and encephalitis (inflammation of the brain) among them. Babies under 1, teenagers, adults and anyone with a weakened immune system are more likely to become seriously unwell.

See a doctor the same day if your child:

• Is under 1 year old, or has a weakened immune system, and has chickenpox or has been exposed to it
• Has skin around the blisters that becomes very red, hot, swollen or painful, or blisters that ooze pus
• Has a fever that lasts more than four days, or a fever that goes away and comes back
• Has spots near or in the eyes, or a sore, red eye
• Is drinking much less than usual or showing signs of dehydration, such as fewer wet nappies

The chickenpox vaccine in Singapore

Vaccination is the most effective way to prevent chickenpox. Under the National Childhood Immunisation Schedule (NCIS), children have two doses of varicella vaccine, as shown in our baby vaccination schedule.

NCIS vaccines are fully subsidised for Singapore Citizen children at polyclinics and participating CHAS GP clinics.

Vaccinated children can still occasionally catch chickenpox, known as breakthrough chickenpox. It is usually much milder, with fewer spots and less fever, but it is still contagious, so the same stay-home rule applies until the spots have crusted.

The chickenpox vaccine is a live vaccine, so it is not given during pregnancy. Our guide to vaccines during pregnancy explains which jabs are recommended and which to avoid.

Preventing spread at home

Keep your sick child apart from unvaccinated younger siblings where you can, wash hands after applying lotion to the blisters, and don’t share towels or bedding. Check that adults at home, including your helper and grandparents, have had chickenpox or the vaccine, and watch siblings for spots over the next three weeks.

The bottom line

• Chickenpox causes an itchy rash of spots, blisters and scabs, and is usually mild in healthy children
• Keep your child home until all the blisters have crusted over, usually five to seven days after the rash starts
• Use fluids, cool clothing, calamine and short nails to ease the itch; paracetamol for fever as per the label
• Never give aspirin, and check with a doctor before using ibuprofen
• Two doses of varicella vaccine at 12 and 15 months are part of Singapore’s NCIS

Read more on HealthHub’s chickenpox page, or browse our baby health hub.