Chickenpox is a highly contagious illness that spreads easily from person to person. It is caused by the varicella-zoster virus.
Chickenpox can cause fever, poor appetite, and tiredness followed by an itchy rash. It is contagious from 1–2 days before the rash appears until the rash has dried up.
In most children, chickenpox is a mild illness and goes away on its own. But it can be a serious illness in a person who is immunocompromised (has a weak immune system). Possible complications include skin infections, pneumonia, and brain swelling.
Chickenpox vaccination works very well to prevent the illness. Talk to your health care provider about the varicella vaccine. Children with weak immune systems cannot get the vaccine because it contains live virus.
Signs and symptoms of chickenpox include:
- Fever
- Tiredness
- Poor appetite
- Headache
- Stomachache
- Skin rash that moves through stages
The rash usually starts on the face and upper body. Then it spreads across the whole body, including the scalp, groin, and inside the mouth, nose, and ears.
- The chickenpox rash appears 10–21 days after your child is exposed to the virus.
- The rash begins as pink dots with small blisters on top filled with clear fluid. After about 24 hours, fluid in the blisters may get cloudy. Then the blisters begin to break open and crust over.
- Chickenpox blisters develop in waves. After some spots break, new spots may appear.
- Blisters usually stop appearing by day 3 or 4. By day 6, all blisters should scab and start to heal.
- It can take 1-2 weeks for all scabs to fall off. Some of the sores may leave spots or scars, that usually fade with time.
In a child with a weak immune system, the rash is often more severe and lasts longer.
Your health care provider will do a physical exam and ask about symptoms and possible exposure to the virus.
Chickenpox is usually easy to diagnose by looking at the skin rash. To confirm a chickenpox diagnosis, your health care provider may:
- Test blister fluid in the lab
- Do a tissue study on a skin sample
Most people with chickenpox will recover on their own with supportive care to manage symptoms. To help manage symptoms of chickenpox:
- Drink plenty of fluids.
- Rest.
- Take a cool bath or shower or use a cold compress on the rash.
- Treat symptoms using over-the-counter medicines as recommended by your care team.
Most people recover in 3–6 days, but recovery may take longer in people with weak immune systems.
If your child has a weak immune system and gets chickenpox, they may need treatment with antiviral medicines. In some cases, they may need to be hospitalized for treatment.
Watch for worsening of symptoms or health problems such as ear infections or diarrhea. Monitor for emergency warning signs such as dehydration, seizures, decrease in level of consciousness, or breathing problems. Seek medical care if symptoms get worse or do not improve.
The vaccine for chickenpox is the varicella vaccine. It contains a weakened form of the virus that protects against developing the illness.
Children usually get 2 doses of varicella vaccine given as a shot:
- Babies usually get the first dose after their first birthday.
- Children get another dose between 4 and 6 years of age.
Some people may get an MMRV vaccine, which protects against measles, mumps, rubella, and varicella (chickenpox).
Chickenpox vaccine in children with weak immune systems
The chickenpox vaccine contains a live strain of varicella virus. The strain in the vaccine is weaker than the actual virus. It is harmless to people with normal immune systems. But children with weak immune systems cannot get the chickenpox vaccine because it contains live virus.
Talk to your care team about vaccines for family caregivers and siblings. When all other family members are vaccinated, it helps provide a circle of protection around the patient.
Chickenpox spreads through the air by droplets that contain the virus, usually from coughing and sneezing. It can also spread through body-to-body contact (touching).
Chickenpox passes easily from person to person. If you or your child have been near someone with chickenpox, then you have been exposed to the virus. The illness cannot spread after the blisters fully dry and heal.
Children do not usually get chickenpox again after they have it for the first time. But the virus stays in the body.
After a person has chickenpox, the varicella-zoster virus can reactivate later in life and cause shingles. Shingles is an illness marked by a painful rash.
Shingles is more common in adults. But anyone who has had chickenpox can get it. Shingles is more common in people with immune systems weakened by:
Usually, shingles cannot spread person to person. But a person who never had chickenpox and is not vaccinated can develop chickenpox after being exposed to a person with shingles.
What to do if your child is exposed to chickenpox
Being around someone with chickenpox or shingles is a danger to a child with a weak immune system who has never had chickenpox or the vaccine. Tell your care team right away if your child is exposed to chickenpox. Your child’s doctor might suggest medicine or another treatment.
Children exposed to chickenpox should avoid immunocompromised children for several weeks. This will reduce the chance of giving the virus to another child.
If you have not been vaccinated or if you are not sure if you have immunity, talk to your health care provider about getting the varicella vaccine.
When to call your child’s care team
Children with weak immune systems are at higher risk of infection. Call a member of your care team right away if your child:
- Has blisters or a rash
- Is exposed to chickenpox or shingles
Your care team can help you decide if there is cause for concern. They will also check your child’s condition to decide if your child can be near other patients.
If you have questions about chickenpox or your child’s risk, please talk to your care team.
Questions to ask your child’s care team
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Reviewed: September 2024
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