Medical Conditions

Chicken Pox (Varicella) in Babies and Toddlers

Medically reviewed by Dr. Michael Okonkwo, MD, FAAP · Board-Certified Neonatologist

Content reviewed against published CDC, AAP, CDC guidelines

Editorial policy

Last reviewed:

If your baby has been diagnosed with or you suspect chicken pox (varicella) in babies and toddlers, here is what the evidence says.

The short answer

Chicken pox (varicella) is a highly contagious viral infection that causes an itchy rash of small, fluid-filled blisters. Thanks to the varicella vaccine, it is much less common than in previous decades, but it can still occur in unvaccinated children or as a mild breakthrough case in vaccinated children. The rash typically appears in waves over 3-5 days, with bumps progressing from red spots to blisters to scabs. Most children recover fully at home within 1-2 weeks.

Key takeaways

  • Chicken pox (varicella) is a highly contagious viral infection that causes an itchy rash of small, fluid-filled blisters. Thanks to the varicella vaccine, it is much less common than in previous decades, but it can still occur in unvaccinated children or as a mild breakthrough case in vaccinated children. The rash typically appears in waves over 3-5 days, with bumps progressing from red spots to blisters to scabs. Most children recover fully at home within 1-2 weeks.
  • Usually normal when: A rash that starts as small red bumps, becomes fluid-filled blisters, and then crusts over
  • Call your doctor if: Your baby is under 4 weeks old and has been exposed to or develops chicken pox
  • Varies by age — see the age-by-age breakdown below
“Fever itself is not an illness — rather, it is a sign or symptom that the body is fighting an infection. Fever stimulates certain defenses, such as the white blood cells, which attack and destroy invading bacteria.”
— Fever and Your Child, American Academy of Pediatrics (AAP)

This is one of the most common questions parents ask. Searching for answers means you care.

What Parents Should Know

According to CDC, AAP guidelines, chicken pox (varicella) is a highly contagious viral infection that causes an itchy rash of small, fluid-filled blisters. Thanks to the varicella vaccine, it is much less common than in previous decades, but it can still occur in unvaccinated children or as a mild breakthrough case in vaccinated children. The rash typically appears in waves over 3-5 days, with bumps progressing from red spots to blisters to scabs. Most children recover fully at home within 1-2 weeks. At 0-6 months, babies under 6 months are partially protected by maternal antibodies if the mother had chicken pox or was vaccinated. However, chicken pox in very young infants can be more serious. Neonatal varicella (if the mother develops chicken pox around the time of delivery) is a medical emergency. If a young baby is exposed to chicken pox, contact your pediatrician promptly as preventive treatment may be available. It is generally considered normal when a rash that starts as small red bumps, becomes fluid-filled blisters, and then crusts over. However, you should contact your pediatrician promptly if your baby is under 4 weeks old and has been exposed to or develops chicken pox.

Sources: [1], [2], [3]

Normal vs. Concerning

Usually Normal
Worth Discussing
A rash that starts as small red bumps, becomes fluid-filled blisters, and then crusts over
Your baby is under 4 weeks old and has been exposed to or develops chicken pox
New crops of blisters appearing for 3-5 days while older ones are healing
Blisters become very red, swollen, warm, or produce pus, indicating bacterial superinfection
Low-grade fever, mild headache, and decreased appetite for the first few days
Your child develops a high fever (over 104F / 40C), especially one that returns after initially improving
Itchiness that peaks when blisters are forming and improves as they scab
Your child seems very ill, confused, has a stiff neck, or has difficulty walking

When to Seek Immediate Care

  • Your baby is under 4 weeks old and has been exposed to or develops chicken pox
  • Blisters become very red, swollen, warm, or produce pus, indicating bacterial superinfection
  • Your child develops a high fever (over 104F / 40C), especially one that returns after initially improving
  • Your child seems very ill, confused, has a stiff neck, or has difficulty walking
  • Your child has a weakened immune system and develops chicken pox
  • Your child develops difficulty breathing or a persistent cough during chicken pox

By Age

What to expect by age

0-6 months

Babies under 6 months are partially protected by maternal antibodies if the mother had chicken pox or was vaccinated. However, chicken pox in very young infants can be more serious. Neonatal varicella (if the mother develops chicken pox around the time of delivery) is a medical emergency. If a young baby is exposed to chicken pox, contact your pediatrician promptly as preventive treatment may be available.

6-12 months

Babies between 6 and 12 months have lost most maternal antibodies but are not yet old enough for the first dose of varicella vaccine (given at 12 months). This makes them vulnerable if exposed. If your baby develops chicken pox at this age, the rash typically starts on the trunk, face, and scalp and spreads outward. Oatmeal baths, calamine lotion, and keeping nails short can help manage itching. Do not give aspirin to children with chicken pox due to the risk of Reye syndrome.

1-3 years

The first dose of varicella vaccine is given at 12-15 months. Vaccinated children can still get a mild case called "breakthrough varicella," which typically involves fewer than 50 lesions and milder symptoms. Unvaccinated toddlers tend to have more severe cases with 200-500 blisters. The rash appears in "crops" over several days, so you will see bumps at different stages (spots, blisters, and scabs) all at once. Children are contagious from 1-2 days before the rash until all blisters have crusted over.

What to Tell Your Pediatrician

  • Describe when you first noticed chicken pox (varicella) in babies and toddlers and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if your baby has been exposed to chicken pox and is under 12 months or unvaccinated.
  • Mention if the rash is very widespread with many blisters, especially in an unvaccinated child.
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

What Should You Do?

When to take action

Probably normal when...
  • A rash that starts as small red bumps, becomes fluid-filled blisters, and then crusts over
  • New crops of blisters appearing for 3-5 days while older ones are healing
  • Low-grade fever, mild headache, and decreased appetite for the first few days
  • Itchiness that peaks when blisters are forming and improves as they scab
  • A milder case with fewer blisters in a vaccinated child
Mention at your next visit when...
  • Your baby has been exposed to chicken pox and is under 12 months or unvaccinated
  • The rash is very widespread with many blisters, especially in an unvaccinated child
  • Your child has been itching severely and you need guidance on comfort measures
  • You are unsure whether your child's rash is chicken pox or something else
Act now when...
  • Your baby is under 4 weeks old and has been exposed to or develops chicken pox
  • Blisters become very red, swollen, warm, or produce pus, indicating bacterial superinfection
  • Your child develops a high fever (over 104F / 40C), especially one that returns after initially improving
  • Your child seems very ill, confused, has a stiff neck, or has difficulty walking
  • Your child has a weakened immune system and develops chicken pox
  • Your child develops difficulty breathing or a persistent cough during chicken pox

What You Can Do at Home

  • Keep track of when you notice chicken pox (varicella) in babies and toddlers — noting the time of day, duration, and any triggers can help your pediatrician.
  • Remember that a rash that starts as small red bumps, becomes fluid-filled blisters, and then crusts over — this is generally within the range of normal.
  • At 0-6 months, focus on observation rather than intervention unless your pediatrician advises otherwise.
  • Follow any care instructions from your pediatrician. Keep a written log of symptoms to bring to appointments.
  • While monitoring at home, seek immediate care if your baby is under 4 weeks old and has been exposed to or develops chicken pox.

My Baby Has a Fever and a Rash

The combination of fever and rash in a baby is very common and is usually caused by a viral infection such as roseola, hand-foot-and-mouth disease, or other viral exanthems. A rash that appears after a fever breaks (as in roseola) is typically benign. However, certain fever-rash combinations, particularly non-blanching purple spots (petechiae or purpura), require immediate medical attention.

Baby Hives (Urticaria)

Hives are raised, red, itchy welts that can appear suddenly on your baby's skin. They are most often caused by a viral infection or an allergic reaction to food, medication, or an insect bite. While they can look alarming, hives are usually harmless and resolve on their own, though any breathing difficulty needs immediate emergency care.

Blisters on Baby's Skin - Causes and When to Worry

Blisters on a baby's skin can have many causes ranging from harmless (sucking blisters, friction blisters) to conditions requiring medical attention (burns, infections like hand-foot-and-mouth disease, impetigo, or herpes). A single blister on a newborn's lip or hand from sucking is very common and harmless. Multiple blisters, blisters with fever, blisters that spread rapidly, or blisters in a newborn under 1 month should be evaluated by a doctor.

My Baby Has a Viral Rash

Viral rashes are extremely common in babies and young children and appear as widespread pink or red spots, often during or after a viral illness like a cold. They are caused by the body's immune response to the virus, not by anything contagious on the skin itself. Most viral rashes are harmless and fade on their own within a few days without any treatment.

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Frequently asked questions

Is chicken pox (varicella) in babies and toddlers normal?
Chicken pox (varicella) is a highly contagious viral infection that causes an itchy rash of small, fluid-filled blisters. Thanks to the varicella vaccine, it is much less common than in previous decades, but it can still occur in unvaccinated children or as a mild breakthrough case in vaccinated children. The rash typically appears in waves over 3-5 days, with bumps progressing from red spots to blisters to scabs. Most children recover fully at home within 1-2 weeks.
When should I call the doctor about chicken pox (varicella) in babies and toddlers?
Your baby is under 4 weeks old and has been exposed to or develops chicken pox Blisters become very red, swollen, warm, or produce pus, indicating bacterial superinfection Your child develops a high fever (over 104F / 40C), especially one that returns after initially improving
When is chicken pox (varicella) in babies and toddlers normal?
A rash that starts as small red bumps, becomes fluid-filled blisters, and then crusts over New crops of blisters appearing for 3-5 days while older ones are healing Low-grade fever, mild headache, and decreased appetite for the first few days
What causes chicken pox (varicella) in babies and toddlers?
Chicken pox (varicella) is a highly contagious viral infection that causes an itchy rash of small, fluid-filled blisters. Thanks to the varicella vaccine, it is much less common than in previous decades, but it can still occur in unvaccinated children or as a mild breakthrough case in vaccinated children. The rash typically appears in waves over 3-5 days, with bumps progressing from red spots to blisters to scabs. Most children recover fully at home within 1-2 weeks. Common explanations include: A rash that starts as small red bumps, becomes fluid-filled blisters, and then crusts over. New crops of blisters appearing for 3-5 days while older ones are healing.
What should I mention to my pediatrician about chicken pox (varicella) in babies and toddlers?
You should mention chicken pox (varicella) in babies and toddlers at your next visit if: Your baby has been exposed to chicken pox and is under 12 months or unvaccinated. The rash is very widespread with many blisters, especially in an unvaccinated child. Your child has been itching severely and you need guidance on comfort measures.
Is chicken pox (varicella) in babies and toddlers normal at 0-6 months?
Babies under 6 months are partially protected by maternal antibodies if the mother had chicken pox or was vaccinated. However, chicken pox in very young infants can be more serious. Neonatal varicella (if the mother develops chicken pox around the time of delivery) is a medical emergency. If a young baby is exposed to chicken pox, contact your pediatrician promptly as preventive treatment may be available.
Is chicken pox (varicella) in babies and toddlers normal at 6-12 months?
Babies between 6 and 12 months have lost most maternal antibodies but are not yet old enough for the first dose of varicella vaccine (given at 12 months). This makes them vulnerable if exposed. If your baby develops chicken pox at this age, the rash typically starts on the trunk, face, and scalp and spreads outward. Oatmeal baths, calamine lotion, and keeping nails short can help manage itching. Do not give aspirin to children with chicken pox due to the risk of Reye syndrome.
Should I go to the ER for chicken pox (varicella) in babies and toddlers?
Seek emergency care if your baby is under 4 weeks old and has been exposed to or develops chicken pox, or if blisters become very red, swollen, warm, or produce pus, indicating bacterial superinfection. When in doubt, call your pediatrician's after-hours line for guidance.
Does chicken pox (varicella) in babies and toddlers go away on its own?
In many cases, chicken pox (varicella) in babies and toddlers resolves on its own, especially when a rash that starts as small red bumps, becomes fluid-filled blisters, and then crusts over. By 1-3 years, the first dose of varicella vaccine is given at 12-15 months. Vaccinated children can still get a mild case called "breakthrough varicella," which typically involves fewer than 50 lesions and milder symptoms. Unvaccinated toddlers tend to have more severe cases with 200-500 blisters. The rash appears in "crops" over several days, so you will see bumps at different stages (spots, blisters, and scabs) all at once. Children are contagious from 1-2 days before the rash until all blisters have crusted over.
CDCAAPCDC

References

  1. [1]Centers for Disease Control and Prevention. Chickenpox (Varicella). CDC
  2. [2]American Academy of Pediatrics. Chickenpox. HealthyChildren.org. AAP
  3. [3]Centers for Disease Control and Prevention. Varicella Vaccine Recommendations. CDC

Doctor Visit Checklist

Bring this checklist to your next pediatrician visit to discuss Chicken Pox (Varicella) in Babies and Toddlers.

Things to mention

  • Describe when you first noticed chicken pox (varicella) in babies and toddlers and how it has changed over time.
  • Note your baby's current age and which age-specific patterns you are seeing.
  • Mention if your baby has been exposed to chicken pox and is under 12 months or unvaccinated.
  • Mention if the rash is very widespread with many blisters, especially in an unvaccinated child.
  • Let your doctor know if you have noticed any related concerns, such as changes in feeding, sleep, or movement patterns.
  • Bring a list of any questions or observations you want to discuss at the appointment.

Observations to share

  • Your baby has been exposed to chicken pox and is under 12 months or unvaccinated
  • The rash is very widespread with many blisters, especially in an unvaccinated child
  • Your child has been itching severely and you need guidance on comfort measures

Urgent signs to report immediately

  • Your baby is under 4 weeks old and has been exposed to or develops chicken pox
  • Blisters become very red, swollen, warm, or produce pus, indicating bacterial superinfection
  • Your child develops a high fever (over 104F / 40C), especially one that returns after initially improving

My notes

From ismybabyalright.com — free, evidence-based baby health guides

All content follows our editorial policy and is reviewed against published clinical guidelines.

2,705 evidence-based guides6 authoritative medical sources5 medical advisory board members

Related Resources

Well-Baby Visit PrepVaccine TrackerEmergency ContactsBaby Tracker

Bottom line

Most cases of chicken pox (varicella) in babies and toddlers are normal. Talk to your pediatrician if your baby is under 4 weeks old and has been exposed to or develops chicken pox.

Trust your instincts. If something feels wrong, reach out to your pediatrician. Worrying about your baby means you care — that is a good thing.

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My Baby Has a Fever and a Rash

The combination of fever and rash in a baby is very common and is usually caused by a viral infection such as roseola, hand-foot-and-mouth disease, or other viral exanthems. A rash that appears after a fever breaks (as in roseola) is typically benign. However, certain fever-rash combinations, particularly non-blanching purple spots (petechiae or purpura), require immediate medical attention.

Baby Hives (Urticaria)

Hives are raised, red, itchy welts that can appear suddenly on your baby's skin. They are most often caused by a viral infection or an allergic reaction to food, medication, or an insect bite. While they can look alarming, hives are usually harmless and resolve on their own, though any breathing difficulty needs immediate emergency care.

Blisters on Baby's Skin - Causes and When to Worry

Blisters on a baby's skin can have many causes ranging from harmless (sucking blisters, friction blisters) to conditions requiring medical attention (burns, infections like hand-foot-and-mouth disease, impetigo, or herpes). A single blister on a newborn's lip or hand from sucking is very common and harmless. Multiple blisters, blisters with fever, blisters that spread rapidly, or blisters in a newborn under 1 month should be evaluated by a doctor.

My Baby Has a Viral Rash

Viral rashes are extremely common in babies and young children and appear as widespread pink or red spots, often during or after a viral illness like a cold. They are caused by the body's immune response to the virus, not by anything contagious on the skin itself. Most viral rashes are harmless and fade on their own within a few days without any treatment.

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