Chickenpox: Symptoms, Treatment & When to Seek Care

What Is Chickenpox and What Causes It?

Chickenpox (varicella) is a highly contagious infection caused by the varicella-zoster virus (VZV), a member of the herpesvirus family. It causes a characteristic itchy rash with fluid-filled blisters, fever, and fatigue. Almost everyone who has not been vaccinated or previously infected will catch chickenpox if exposed to the virus.

Chickenpox has been one of the most common childhood infections throughout history, though vaccination programs have dramatically reduced its incidence in many countries. Before widespread vaccination, approximately 4 million cases occurred annually in the United States alone, with similar rates across other developed nations. The disease remains common in countries without routine vaccination programs.

The varicella-zoster virus belongs to the same family as the viruses that cause cold sores (herpes simplex) and infectious mononucleosis (Epstein-Barr virus). Unlike many viral infections that leave the body after recovery, VZV remains dormant in nerve cells for life. This dormant virus can reactivate decades later, causing a different condition called shingles (herpes zoster).

The name "chickenpox" has uncertain origins but may derive from the Old English word "gican" meaning "to itch," or from the resemblance of the blisters to chickpeas. Despite its name, chickens are not involved in transmitting this disease to humans.

How Does Chickenpox Spread?

Chickenpox is extraordinarily contagious—one of the most transmissible diseases known. The virus spreads through two main routes. First, it transmits through tiny respiratory droplets released when an infected person breathes, coughs, or sneezes. These droplets can travel through the air and be inhaled by nearby people. Second, the virus spreads through direct contact with fluid from the characteristic blisters.

A person with chickenpox is contagious from approximately 1-2 days before the rash appears until all blisters have formed scabs—typically about 5-7 days after the rash starts. This early contagious period before symptoms appear makes it difficult to prevent transmission, as infected individuals often unknowingly expose others before realizing they are sick.

In household settings, the transmission rate to susceptible family members exceeds 85-90%. This explains why chickenpox often spreads rapidly through schools, childcare centers, and families. When one child in a daycare develops chickenpox, most unvaccinated children will likely become infected.

What Are the Symptoms of Chickenpox?

Chickenpox symptoms begin with fever, headache, and fatigue 1-2 days before the characteristic rash appears. The rash starts as red spots that develop into itchy, fluid-filled blisters over 12-24 hours. New blisters continue forming for several days, meaning spots at different stages appear simultaneously. Most blisters crust over within 5-7 days.

The journey from infection to recovery follows a predictable pattern, though the severity varies considerably between individuals. Children typically experience milder symptoms than adults, who often develop more extensive rash, higher fevers, and feel significantly more unwell.

Initial Symptoms (Prodrome Phase)

Before the rash appears, most people experience a period of feeling generally unwell that lasts 1-2 days. During this prodrome phase, common symptoms include mild to moderate fever (usually between 38-39°C or 100.4-102.2°F), headache, loss of appetite, fatigue and general malaise, and sometimes a mild sore throat. In adults, this prodrome phase is often more pronounced and may include muscle aches and more significant fatigue.

The Characteristic Rash

The hallmark of chickenpox is its distinctive rash, which progresses through several stages. The rash typically begins on the trunk (chest, back, and abdomen) and face before spreading to the arms, legs, and sometimes inside the mouth, on the scalp, or around the genitals.

Each spot evolves through a predictable sequence. It starts as a small red bump (macule), then develops a raised area (papule), which then fills with clear fluid to form a blister (vesicle). The blister eventually becomes cloudy, breaks, and forms a scab (crust). This entire progression takes about 24-48 hours for each individual spot.

A distinctive feature of chickenpox is that new crops of spots continue to appear for 3-5 days. This means that at any given time during the illness, spots at different stages of development are visible simultaneously—some as fresh red bumps, others as fluid-filled blisters, and others already forming scabs. This "crops of lesions" appearance is characteristic of chickenpox and helps distinguish it from other rash-causing illnesses.

Symptoms Are Usually Milder in Children

Children, particularly those under 10 years old, typically have the mildest course of illness. They may have only 200-300 spots, relatively low-grade fever, and remain fairly active throughout the illness. Many children continue to want to play and eat normally, with itching being their main complaint.

Adults and adolescents, in contrast, often experience more severe symptoms. They typically develop more extensive rash (sometimes over 500 spots), higher fevers that may persist longer, more pronounced fatigue and feeling of illness, and greater risk of complications such as pneumonia. Adults should seek medical attention promptly if they develop chickenpox, as early antiviral treatment can reduce severity.

How Long Do Symptoms Last?

For children, the acute illness typically lasts about 5-7 days, with full recovery including healing of all scabs taking 1-2 weeks. Adults may take longer to recover, sometimes requiring 2-3 weeks before feeling completely well. The scabs can leave temporary pink or brown marks that may persist for weeks to months but usually fade completely without scarring, unless the blisters became infected or were severely scratched.

When Should You See a Doctor for Chickenpox?

Seek medical care immediately if you are an adult with chickenpox, pregnant, immunocompromised, or have a newborn with symptoms. Also contact a doctor for high fever lasting more than 4 days, signs of skin infection (spreading redness, pus), difficulty breathing, persistent vomiting, severe headache, or unusual drowsiness.

While chickenpox is usually a self-limiting illness that resolves without treatment, certain situations require medical attention. Recognizing when to seek care is important for preventing complications.

Seek Care Immediately For Adults

If you are 18 years or older and develop chickenpox, you should contact a healthcare provider promptly. Adults are at significantly higher risk for complications, and antiviral medication (typically valacyclovir or acyclovir) can reduce the severity and duration of illness if started within 24 hours of the rash appearing. Don't wait to see how the illness progresses—early treatment makes a meaningful difference.

High-Risk Groups Requiring Immediate Medical Attention

Certain groups face elevated risks from chickenpox and should receive medical evaluation as soon as possible after exposure or at the first sign of symptoms. Pregnant women who have not had chickenpox and are exposed should contact their healthcare provider immediately for possible preventive treatment. Newborns, especially those under 4 weeks old whose mothers have not had chickenpox, require urgent evaluation. People with weakened immune systems (from cancer treatment, HIV, organ transplants, or immunosuppressive medications) need immediate care. Additionally, anyone currently taking steroids or other immunosuppressive medications should seek prompt medical attention.

When to Seek Care for Children

Contact a healthcare provider for children with chickenpox in the following situations: persistent high fever (over 38.5°C/101.3°F) lasting more than 4 days, fever that returns after initially improving, extensive rash in mouth causing difficulty eating or drinking, signs of dehydration, severe itching not relieved by home remedies, any signs of skin infection (increasing redness, swelling, warmth, or pus), new cough or difficulty breathing after blisters appear, and unusual sleepiness or behavior changes.

Special Considerations for Infants

Babies under 6 months whose mothers have had chickenpox usually have some protection from maternal antibodies passed during pregnancy and through breastfeeding. However, infants in this age group should still be evaluated by a healthcare provider if they develop symptoms.

If the mother has never had chickenpox, the infant has no maternal antibody protection and is at higher risk for severe disease. These babies may need preventive treatment with immunoglobulin (VZIG) if exposed to chickenpox.

Always Call Before Visiting

Because chickenpox is highly contagious, you should always phone ahead before visiting any healthcare facility. This allows staff to arrange appropriate precautions to prevent exposing other patients, particularly vulnerable individuals like pregnant women and immunocompromised patients in waiting rooms.

How Is Chickenpox Treated?

Chickenpox treatment focuses on relieving symptoms, primarily itching and fever. Use paracetamol (acetaminophen) for fever—avoid ibuprofen and aspirin. Apply calamine lotion or cool compresses for itching, and consider antihistamines. Keep nails short to prevent scratching. Adults and high-risk patients may receive antiviral medication such as acyclovir or valacyclovir.

For most healthy children, chickenpox requires only supportive care at home while the body's immune system clears the infection. The focus is on keeping the patient comfortable, preventing scratching (which can lead to scarring and secondary infection), and watching for signs of complications.

Managing Fever Safely

Fever can be treated with paracetamol (acetaminophen), following appropriate dosing for age and weight. However, two important medication warnings apply to chickenpox:

Relieving the Itch

The intense itching of chickenpox can be distressing and may lead to scratching that causes scarring or secondary infection. Several approaches can help relieve this discomfort:

Topical treatments provide direct relief to affected skin. Calamine lotion has been used for generations to soothe itchy chickenpox rash. Cooling gels and lotions can provide temporary relief. Cool, wet compresses applied to itchy areas help reduce discomfort. Oatmeal baths (colloidal oatmeal products or finely ground oatmeal added to lukewarm bathwater) soothe the skin and reduce itching. However, avoid using creams or ointments containing hydrocortisone, as these may increase the risk of bacterial infection in chickenpox lesions.

Oral antihistamines can help reduce itching, especially at night when it may interfere with sleep. Over-the-counter options containing diphenhydramine or loratadine are commonly used. Some antihistamines cause drowsiness, which may actually be helpful for getting rest but should be used carefully during the day. Ask a pharmacist for age-appropriate recommendations.

Preventing scratching is crucial for avoiding scarring and infection. Keep fingernails short and smooth. Consider cotton gloves or mittens at night for children. Distraction activities can help children focus on something other than the itch. Loose, comfortable cotton clothing reduces irritation.

Keeping the Skin Clean

Contrary to old advice to avoid bathing, keeping the skin clean is important during chickenpox. Regular bathing with mild soap helps prevent bacterial infection of the blisters. Pat skin dry gently rather than rubbing. Lukewarm water is best—hot water may increase itching.

Antiviral Treatment for High-Risk Patients

Antiviral medications such as acyclovir or valacyclovir can reduce the severity and duration of chickenpox, but they are most effective when started within 24 hours of the rash appearing. These medications are typically recommended for adults with chickenpox (who have higher complication rates), people with compromised immune systems, newborns and infants whose mothers developed chickenpox around the time of delivery, and individuals with chronic skin or lung conditions.

For healthy children, antiviral treatment is generally not necessary as the illness is typically mild. However, some healthcare providers may recommend treatment for secondary household cases (who often have more severe illness) or adolescents.

Treatment for Mouth Sores

When chickenpox blisters develop inside the mouth, they can make eating and drinking painful. Cold, soft foods like popsicles, ice cream, and smoothies are often tolerated better. Avoid salty, spicy, or acidic foods that irritate mouth sores. Staying well hydrated is important—offer frequent small sips of water or other fluids.

What Complications Can Chickenpox Cause?

Most chickenpox cases resolve without complications, but risks include bacterial skin infections (the most common complication), pneumonia (especially in adults), encephalitis (brain inflammation), and dehydration. Pregnant women face risks of birth defects if infected during early pregnancy or severe newborn infection if infected near delivery.

While chickenpox is usually a mild, self-limiting illness in healthy children, complications do occur. Understanding these potential complications helps in recognizing warning signs that require medical attention.

Bacterial Skin Infections

The most common complication of chickenpox is secondary bacterial infection of the blisters. Bacteria (typically Staphylococcus or Streptococcus) can enter through broken blisters, especially those that have been scratched. Signs of bacterial infection include increasing redness spreading beyond the blister, warmth and swelling around lesions, pus or cloudy fluid, fever returning after initial improvement, and red streaks extending from lesions.

In rare cases, these infections can become serious, leading to cellulitis (deep skin infection), sepsis (bloodstream infection), or necrotizing fasciitis (a severe infection of deeper tissues). This is one reason why avoiding NSAIDs like ibuprofen is recommended during chickenpox—they may mask early signs of bacterial infection.

Pneumonia

Chickenpox pneumonia occurs when the virus infects the lungs. This complication is much more common in adults than children, occurring in about 1 in 400 adult cases. It typically develops 3-5 days after the rash appears. Symptoms include cough, rapid breathing, difficulty breathing, and chest pain. Adults who develop respiratory symptoms should seek medical care promptly.

Neurological Complications

Rarely, chickenpox can affect the nervous system. Cerebellar ataxia causes temporary balance and coordination problems, usually appearing a few days to weeks after the rash. Most children recover completely. Encephalitis (brain inflammation) is rare but serious, causing severe headache, confusion, seizures, or altered consciousness. This requires immediate medical attention.

Complications in Pregnancy

Chickenpox during pregnancy poses risks to both mother and baby. Infection in the first 20 weeks of pregnancy can rarely cause congenital varicella syndrome, which may include limb abnormalities, scarring, eye problems, and neurological issues. The risk is low (about 1-2%) but serious. Infection near delivery (within 5 days before to 2 days after birth) can cause severe neonatal chickenpox in the newborn, as the baby is exposed without having received protective antibodies from the mother.

Long-Term: Risk of Shingles

After chickenpox resolves, the varicella-zoster virus does not leave the body. Instead, it remains dormant in nerve cells near the spine. Later in life—often decades later—the virus can reactivate, causing shingles (herpes zoster). Shingles typically appears as a painful, blistering rash on one side of the body, often in a band-like pattern. Learn more about shingles

How Can Chickenpox Be Prevented?

The varicella vaccine is highly effective, preventing approximately 90% of infections with one dose and over 98% with two doses. The vaccine is typically given at ages 12-15 months and 4-6 years. For those already exposed, the vaccine may prevent or reduce illness if given within 3-5 days of exposure.

Prevention of chickenpox has been transformed by the development of an effective vaccine. Before vaccination programs began in the 1990s, chickenpox was nearly universal—almost every child caught the disease. Today, in countries with routine vaccination, cases have dropped dramatically.

The Varicella Vaccine

The chickenpox vaccine contains a weakened (attenuated) form of the varicella-zoster virus. This live vaccine stimulates the immune system to produce protective antibodies without causing significant illness. The vaccine has an excellent safety record and has been given to millions of people worldwide.

Vaccine effectiveness is impressive. A single dose prevents about 85% of all chickenpox cases and over 95% of severe cases. Two doses increase protection to over 98%. Even in the rare cases where vaccinated individuals develop chickenpox (called "breakthrough chickenpox"), the illness is typically much milder, with fewer blisters, less fever, and faster recovery.

Who Should Be Vaccinated?

In countries where the vaccine is part of routine immunization programs, the standard schedule is a first dose at 12-15 months of age and a second dose at 4-6 years of age. Adults and adolescents who have never had chickenpox or been vaccinated should receive two doses, given 4-8 weeks apart.

Certain groups should particularly consider vaccination: healthcare workers who may be exposed to chickenpox, teachers and childcare workers, women planning pregnancy who have not had chickenpox (but not during pregnancy), international travelers to areas where chickenpox is common, and household contacts of immunocompromised people.

Who Should Not Receive the Vaccine?

Because the chickenpox vaccine contains live virus (though weakened), certain people should not receive it. Pregnant women should not be vaccinated, and women should avoid becoming pregnant for one month after vaccination. People with severely weakened immune systems (from diseases or medications) may not be able to receive the vaccine safely. Anyone who has had a severe allergic reaction to a previous dose or vaccine components should not receive it. Those currently ill with fever should wait until recovery.

Post-Exposure Prevention

If someone is exposed to chickenpox, the vaccine can still provide protection if given within 3-5 days of exposure. This post-exposure vaccination can prevent infection entirely or significantly reduce severity. This approach is particularly valuable for household contacts of someone with chickenpox.

For high-risk individuals who cannot receive the vaccine, varicella-zoster immune globulin (VZIG) can provide temporary protection if given within 10 days of exposure. This is typically reserved for newborns, pregnant women without immunity, and severely immunocompromised individuals.

Preventing Spread During Illness

If someone has chickenpox, the following measures help prevent spreading the infection to others. Keep the infected person home until all blisters have crusted over (usually 5-7 days after the rash starts). Avoid contact with high-risk individuals: pregnant women who haven't had chickenpox, newborns, and immunocompromised people. Practice good hand hygiene—wash hands frequently, especially after touching the rash. Cover the nose and mouth when coughing or sneezing. Don't share personal items like towels or utensils. Notify the school, daycare, or workplace so others can be alerted to potential exposure.

What About Chickenpox During Pregnancy?

Chickenpox during pregnancy can pose risks to both mother and baby. The risk of birth defects (congenital varicella syndrome) is about 1-2% if infection occurs in the first 20 weeks. Infection near delivery poses the highest risk, as the newborn may develop severe chickenpox. Pregnant women without immunity who are exposed should receive treatment immediately.

Chickenpox during pregnancy requires special attention due to potential risks to both the pregnant woman and the developing baby. Fortunately, most women of childbearing age have immunity from previous infection or vaccination, but those without immunity face important considerations.

Risks to the Mother

Pregnant women who develop chickenpox are at higher risk for complications than non-pregnant adults. Varicella pneumonia, in particular, is more common and more severe during pregnancy, especially in the second and third trimesters. This is one reason why pregnant women without immunity should seek medical care immediately if exposed to chickenpox.

Risks to the Baby

The timing of infection during pregnancy determines the risks to the baby. Infection in the first 20 weeks of pregnancy carries a small risk (about 1-2%) of congenital varicella syndrome, which can cause skin scarring in a dermatomal pattern, limb abnormalities (hypoplasia), eye problems (cataracts, chorioretinitis), and neurological problems.

Infection between 20-36 weeks of pregnancy rarely causes problems for the baby, as the maternal immune response provides some protection. However, infection within 5 days before to 2 days after delivery is the highest-risk period. The baby may be exposed to the virus without receiving protective maternal antibodies, potentially leading to severe neonatal chickenpox. Babies in this situation are typically treated with VZIG and sometimes antiviral medication.

What to Do If Exposed During Pregnancy

If you're pregnant and unsure whether you've had chickenpox, a blood test can check for antibodies. If exposed to chickenpox and you're not immune, contact your healthcare provider immediately. You may receive varicella-zoster immune globulin (VZIG), which can prevent or reduce the severity of infection if given within 10 days of exposure.

If you develop chickenpox while pregnant, antiviral treatment with acyclovir may be recommended. Careful monitoring throughout the rest of the pregnancy helps detect any potential effects on the baby.

Planning Pregnancy

Women planning pregnancy who have never had chickenpox or been vaccinated should consider vaccination before becoming pregnant. The vaccine should be given at least one month before attempting to conceive, as it is a live vaccine and should not be given during pregnancy.

Why Is Chickenpox Worse in Adults Than Children?

Adults with chickenpox typically experience more severe symptoms than children, including higher fever, more extensive rash, longer illness duration, and significantly higher rates of complications like pneumonia. Adults should seek medical care promptly for antiviral treatment, which is most effective when started within 24 hours of the rash appearing.

The age at which someone contracts chickenpox significantly influences the severity of illness. While children under 10 typically have mild cases, adults and adolescents face a distinctly more challenging course. Understanding these differences helps guide appropriate care for different age groups.

Differences in Symptom Severity

Adults with chickenpox typically develop a more extensive rash, often with over 500 lesions compared to the 200-300 typical in children. Fever tends to be higher and lasts longer in adults. The prodrome phase (feeling unwell before the rash appears) is usually more pronounced in adults, with significant fatigue, headache, and muscle aches. Adults generally feel much more unwell overall and take longer to recover, often requiring 2-3 weeks compared to 1-2 weeks for children.

Higher Complication Rates

The risk of complications is substantially higher in adults than children. Varicella pneumonia occurs in about 1 in 400 adult cases, compared to much rarer occurrence in children. Adults are also at higher risk for encephalitis and other neurological complications, secondary bacterial infections, and hospitalization.

Why the Difference?

The reasons for increased severity in adults are not completely understood, but several factors likely contribute. The adult immune response to the virus may be more inflammatory, causing more severe symptoms. Adults may have higher viral loads due to delayed immune recognition. Additionally, adults are more likely to have underlying health conditions that increase risk.

Treatment Recommendations for Adults

Due to the increased severity, adults with chickenpox should see a healthcare provider promptly. Antiviral medication is typically recommended for adults and is most effective when started within 24 hours of the rash appearing. Adults should also watch carefully for signs of complications, particularly respiratory symptoms that could indicate pneumonia. Rest and adequate hydration are particularly important for adults, who may need time off work for 1-2 weeks or longer.