Chickenpox (Varicella) in Babies & Children
Content reviewed against published CDC, AAP, CDC guidelines
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Chickenpox is a highly contagious viral illness caused by the varicella-zoster virus (VZV). It causes an itchy, blister-like rash covering the body along with fever and fatigue. Thanks to vaccination, chickenpox is much less common than it once was, but it still occurs in unvaccinated or partially vaccinated children. It is more serious in infants under 1 year who are too young to be vaccinated.
Key takeaways
- Chickenpox is a highly contagious viral illness caused by the varicella-zoster virus (VZV).
- Duration: New lesions appear for 3-5 days. All lesions typically crust over by day 5-7. Total healing takes 1-2 weeks. Crusts fall off over 1-3 weeks.
- Go to ER if: Difficulty breathing or chest pain
- A vaccine or immunization is available
Symptoms
How It Presents by Age
0-6 months
May have milder disease if maternal antibodies are present (mother had chickenpox or was vaccinated). Neonatal varicella (from maternal infection near delivery) can be very severe. Infants without maternal protection can have serious disease.
Risk level: Moderate to high (unprotected infants)
6-12 months
Too young for vaccination. Can develop moderate to severe disease with hundreds of lesions. At higher risk for complications than older children.
Risk level: Moderate
1-4 years
Classic chickenpox presentation. Usually 200-500 lesions in unvaccinated children. Breakthrough chickenpox in vaccinated children is much milder (fewer than 50 lesions, often no fever).
Risk level: Low (vaccinated) to moderate (unvaccinated)
5-12 years
If unvaccinated, can have extensive disease. Vaccinated children who get breakthrough cases are generally mild.
Risk level: Low (vaccinated)
Treatment
Itch relief
Calamine lotion, oatmeal baths, cool compresses, and oral antihistamines (diphenhydramine) for itch relief. Keep nails short to prevent scratching.
Fever management
Acetaminophen only. NEVER give aspirin (risk of Reye syndrome) or ibuprofen (possible increased risk of secondary bacterial skin infections — discuss with doctor).
Acyclovir
Antiviral medication may be recommended for adolescents, adults, immunocompromised patients, or infants. Not routinely given to healthy young children.
Prevent secondary infection
Keep blisters clean. Cut nails short. Use mittens on babies to prevent scratching.
Home Care
- Oatmeal baths (colloidal oatmeal) to soothe itching
- Apply calamine lotion (not on face or near eyes)
- Keep nails very short and clean — put mittens on babies
- Cool, wet compresses on itchy areas
- Dress in loose, soft cotton clothing
- Baking soda baths (1/2 cup in lukewarm water)
- Diphenhydramine (Benadryl) at bedtime for itch (with doctor guidance)
- Distraction — the itching is worst and scratching should be avoided
- Do NOT pop or pick at blisters (increases scarring and infection risk)
When to Worry
Go to the ER if:
- Difficulty breathing or chest pain
- Stiff neck, severe headache, or extreme drowsiness/confusion (possible encephalitis)
- Inability to walk or severe unsteadiness (cerebellar ataxia)
- Widespread redness and swelling of skin (cellulitis or necrotizing fasciitis)
- Very high fever (over 104°F) with extensive rash
- Baby under 1 month with any chickenpox lesions
- Signs of sepsis — mottled skin, very rapid breathing, unresponsive
Call your doctor if:
- Baby under 12 months with confirmed chickenpox exposure or rash
- Fever lasting more than 4 days or fever that returns
- Rash becoming very red, swollen, warm, or painful (signs of bacterial superinfection)
- Rash near or in the eyes
- Child seems very unwell or confused
- Difficulty breathing or persistent cough
- Child with immune deficiency exposed to chickenpox
Keep an eye on:
- Skin around blisters becoming very red, warm, swollen, or painful (bacterial infection)
- Fever returning or new high fever after initial improvement
- Rash spreading to eyes
- More than 500 lesions in a young child
- Extreme lethargy or confusion
Prevention
- Varicella vaccine — first dose at 12-15 months, second dose at 4-6 years
- Vaccine is about 90% effective at preventing any chickenpox and nearly 100% effective at preventing severe disease
- Post-exposure vaccination within 3-5 days of exposure can prevent or reduce severity
- Varicella-Zoster Immune Globulin (VariZIG) for high-risk exposed individuals who cannot be vaccinated
- Isolate infected children until all lesions have crusted
- Pregnant women who are not immune should avoid exposure
Contagion & Incubation
Incubation
10-21 days (average 14-16 days)
Contagious for
1-2 days before rash appears until all lesions have crusted over (usually 5-7 days after rash onset)
Duration
New lesions appear for 3-5 days. All lesions typically crust over by day 5-7. Total healing takes 1-2 weeks. Crusts fall off over 1-3 weeks.
Frequently asked questions
How long does chickenpox (varicella) last?
How does varicella spread?
When should I take my baby to the ER?
Can varicella be prevented?
When can my child return to daycare?
Sources
All content follows our editorial policy and is reviewed against published clinical guidelines.
2,705 evidence-based guides6 authoritative medical sources
Related Illnesses
Bottom line
Chickenpox (Varicella) is a viral illness that typically resolves on its own. Seek emergency care if difficulty breathing or chest pain.
Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.