Varicella (Chickenpox)
The itchy, blistering infection commonly known as chickenpox
Quick Facts
- Type: Viral infection
- Cause: Varicella-zoster virus
- Hallmark: Itchy, blistering rash
- Prevention: Varicella vaccine
Overview
Varicella, commonly known as chickenpox, is a highly contagious infection caused by the varicella-zoster virus. It produces an itchy rash that turns into small, fluid-filled blisters and then scabs over, usually along with fever and feeling generally unwell. Before widespread vaccination, almost everyone caught chickenpox in childhood.
For most healthy children the illness is uncomfortable but mild and resolves within a week or two. However, it can be more serious in newborns, pregnant people, teenagers, adults, and anyone with a weakened immune system. After the infection clears, the virus stays dormant in the body and can reactivate years later as shingles. A safe and effective vaccine has made chickenpox much less common in places where it is widely used.
Symptoms
Symptoms usually appear about one to three weeks after exposure. Early signs may include fever, tiredness, headache, and loss of appetite, often a day or two before the rash. The rash then develops:
- Small red spots that quickly become itchy, fluid-filled blisters
- Blisters that appear in crops, so spots at different stages are present at once
- Blisters that cloud over, burst, and crust into scabs
- A rash that often starts on the chest, back, and face, then spreads
- Sometimes spots inside the mouth, eyelids, or genital area
The person is contagious from about a day or two before the rash until all blisters have crusted over. Severe symptoms or signs of complications need medical attention.
Causes
Chickenpox is caused by the varicella-zoster virus, which spreads very easily from person to person.
- Airborne and droplet spread: The virus travels through the air when an infected person coughs, sneezes, talks, or breathes.
- Direct contact: Touching the fluid from chickenpox blisters can also spread it.
People with shingles can pass the same virus to someone who has never had chickenpox or the vaccine, causing chickenpox in that person. Because it is so contagious, chickenpox can spread quickly through households, schools, and other close settings.
Risk Factors
- Not having had chickenpox or the varicella vaccine
- Close contact with an infected person
- Young children in school or daycare settings
- A weakened immune system, which raises the risk of severe illness
- Pregnancy, newborn period, and adolescence or adulthood, where illness can be more severe
Diagnosis
Chickenpox is usually diagnosed from its appearance:
- Examination: The characteristic itchy rash with blisters at different stages, along with fever, is often enough to make the diagnosis.
- History: Recent exposure to chickenpox or shingles and vaccination status help confirm it.
- Laboratory tests: Rarely needed, but a sample from a blister can confirm the virus if the diagnosis is unclear or in high-risk situations.
Treatment
For most healthy children, treatment focuses on comfort while the illness runs its course.
- Soothing the itch: Cool baths, calamine or other soothing lotions, and keeping nails short to limit scratching and skin infection.
- Fever and discomfort: Paracetamol can be used for fever; aspirin should not be given to children with chickenpox because of the risk of a serious condition.
- Fluids and rest: Plenty of fluids and rest support recovery.
- Antiviral medication: May be prescribed for those at higher risk of severe illness, such as adults, pregnant people, or those with weakened immunity, ideally started early.
Most people recover fully, and the scabs usually heal without scarring unless the spots become infected from scratching.
Prevention
- The varicella vaccine is the most effective way to prevent chickenpox
- Keep infected people away from others until all blisters have crusted over
- Avoid contact between infected people and newborns, pregnant people, and those with weak immune systems
- Wash hands often and avoid sharing items with an infected person
- Those at high risk who are exposed may be offered preventive treatment by a doctor
When to See a Doctor
Contact a doctor if you or your child are at higher risk (such as during pregnancy, in newborns, or with a weakened immune system), or if the illness seems severe. Seek prompt or emergency care for:
- A very high or persistent fever, or the person becoming very unwell
- A rash area that becomes increasingly red, warm, swollen, or oozes pus (possible skin infection)
- Difficulty breathing, a stiff neck, severe headache, confusion, or repeated vomiting
- Trouble walking, drowsiness, or seizures
These can signal complications that need urgent assessment.
Frequently Asked Questions
What is varicella?
Varicella is the medical name for chickenpox, a highly contagious infection caused by the varicella-zoster virus. It produces an itchy, blistering rash along with fever and tiredness and is usually mild in healthy children.
How does chickenpox spread?
It spreads very easily through the air when an infected person coughs, sneezes, or breathes, and by direct contact with the fluid from the blisters. A person is contagious from a day or two before the rash until all the blisters have crusted over.
How can chickenpox be prevented?
The varicella vaccine is the most effective way to prevent it. Keeping infected people away from others until all blisters crust over, and protecting newborns, pregnant people, and those with weak immunity from exposure, also helps.
Is chickenpox dangerous?
For most healthy children it is uncomfortable but mild. It can be more serious in newborns, pregnant people, teenagers, adults, and those with weakened immune systems, who should seek medical advice if exposed or infected.
Can you get chickenpox more than once?
Most people who have had chickenpox are immune for life. However, the virus stays dormant in the body and can reactivate years later as shingles, a different illness affecting a band of skin.
References
- Centers for Disease Control and Prevention (CDC). Chickenpox (Varicella).
- Mayo Clinic. Chickenpox — Symptoms and causes.
- MedlinePlus, U.S. National Library of Medicine. Chickenpox.
- World Health Organization (WHO). Varicella.