Chickenpox, also called varicella, is a common and highly contagious viral infection caused by the varicella-zoster virus (VZV). It spreads easily from person to person and causes an itchy, blister-like rash, fever, and tiredness. Before the chickenpox vaccine became available, nearly every child caught it at some point. Today, vaccination has made chickenpox far less common, but it still appears in people who are unvaccinated or have weakened immune systems. 

For most healthy children, chickenpox is mild and clears up on its own. However, it can be serious for adults, pregnant women, newborns, and people with medical conditions that weaken the immune system. Once a person recovers, the virus stays quietly inside the body and can reactivate years later as shingles. 

Chickenpox is the first infection caused by the varicella-zoster virus. It typically causes a mild fever followed by a very itchy rash that spreads over the body. The rash begins as red spots that turn into fluid-filled blisters before drying into scabs. People with chickenpox are contagious from one to two days before the rash appears until all blisters have crusted over. 

Once someone has had chickenpox, their immune system usually provides lifelong protection. However, the virus stays dormant in nerve cells and can come back later in life as shingles, which causes a painful rash in a single area of the body. 

Before the chickenpox vaccine, almost all children caught the disease during childhood. It spread rapidly in families, schools, and communities. Since the vaccine was introduced, cases and hospitalizations have fallen by more than 90%, showing how effective vaccination can be. 

Chickenpox still occurs among people who aren’t vaccinated or whose immune systems are weak. Infants, pregnant women, and adults who missed vaccination as children are at higher risk of complications. In many regions, the disease is more common during late winter and spring. 

Public health programs continue to promote vaccination, especially in areas where healthcare access is limited, to stop outbreaks and protect vulnerable groups. 

Chickenpox spreads easily in three main ways: 

• Through the air: by coughing or sneezing tiny droplets that contain the virus 

• Through direct contact: by touching the fluid from an infected person’s blisters 

• From mother to baby: during pregnancy, which can cause serious illness in the newborn 

The incubation period—the time from exposure to the first symptoms—is about 10 to 21 days. People are contagious from one to two days before the rash appears until all spots have crusted over. 

Chickenpox starts when a person breathes in droplets from someone who is infected or touches something contaminated with the virus. The virus first multiplies quietly in the nose and throat, then spreads through the bloodstream to the skin, causing the familiar rash. 

Even after recovery, the virus doesn’t completely leave the body—it hides in nerve cells near the spinal cord. It can stay inactive for decades and sometimes reappears as shingles. The body’s immune system keeps it under control, helping prevent reinfection. 

Because chickenpox is so contagious, one infected person can easily spread it to anyone nearby who hasn’t had the disease or the vaccine. 

Chickenpox usually begins about two weeks after exposure. At first, a person may feel tired, cranky, or feverish. Then, the classic itchy rash begins. 

Early signs: 

• Mild fever or headache 

• Loss of appetite 

• Feeling tired or unwell 

The rash: 

• Starts as small red spots that become fluid-filled blisters, then scab over 

• Usually begins on the face, chest, and back before spreading to arms and legs 

• May appear on the scalp or inside the mouth, causing soreness 

• New spots appear for several days, so people often have red bumps, blisters, and scabs all at once 

• The itching can be intense and may make sleeping difficult 

Other symptoms: 

• Swollen glands or sore throat 

• Fatigue lasting a few days 

Most people recover within a week, but scratching can lead to infection and scarring. 

Doctors usually diagnose chickenpox by looking at the rash and reviewing recent exposure history. Because the spots appear in different stages, the diagnosis is often clear. 

In unusual cases or for people at high risk, tests can confirm the diagnosis: 

• PCR test: detects the virus’s genetic material from a blister sample (most accurate test) 

• Blood tests: check for antibodies to show if someone is immune or recently infected 

Differential Diagnosis 

Other conditions can look similar to chickenpox, including: 

• Hand, foot, and mouth disease 

• Insect bites 

• Impetigo (bacterial skin infection) 

• Drug reactions that cause rashes 

• Smallpox (now eradicated but historically similar) 

Doctors can usually tell the difference based on the rash pattern and symptoms. 

Most people recover at home with rest and simple care. Antibiotics don’t help because chickenpox is caused by a virus, but comfort measures can make a big difference. 

Home care tips: 

• Take acetaminophen (Tylenol) for fever or discomfort—avoid aspirin 

• Drink plenty of fluids 

• Use calamine lotion or oatmeal baths to soothe itchy skin 

• Wear soft, loose clothing and keep nails trimmed to avoid scratching 

• Stay home until all blisters have crusted over 

When antivirals are needed: 
Doctors may prescribe antiviral medication such as acyclovir for people who are at higher risk—like adults, pregnant women, newborns, or those with weak immune systems. These medicines work best if started within 24 hours of the rash appearing. 

When to seek medical care: 
Call a doctor right away if you have trouble breathing, confusion, a very high fever, or spreading redness around blisters—these could signal serious complications. 

Chickenpox is usually mild but can sometimes cause serious problems, especially in adults, pregnant women, or those with weak immune systems. 

Possible complications include: 

• Bacterial infections of the skin (impetigo, cellulitis) 

• Pneumonia, especially in adults and smokers 

• Brain inflammation (encephalitis) or loss of coordination (cerebellitis) 

• Liver or kidney inflammation (rare) 

• Reye syndrome, which can occur if aspirin is given to children with chickenpox 

• In pregnancy, varicella can cause congenital varicella syndrome, affecting the baby’s development 

Healthy children almost always recover completely within a week or two. After recovery, most people are immune for life. However, the virus can remain hidden in the body and later cause shingles—a painful, blistering rash that affects specific nerve areas. 

Adults, pregnant women, and immunocompromised individuals have a higher risk of complications, but with proper care and antiviral treatment, recovery is usually excellent. 

The best way to prevent chickenpox is by getting vaccinated. The varicella vaccine is safe, effective, and provides long-lasting protection. 

Vaccine schedule: 

• First dose: 12–15 months old 

• Second dose: 4–6 years old 

Adults who have never had chickenpox or the vaccine should also get vaccinated. The vaccine prevents most cases entirely and makes any breakthrough cases much milder. 

After exposure: 
If someone who isn’t immune is exposed to chickenpox, getting the vaccine within 3–5 days can prevent or lessen symptoms. For people who can’t be vaccinated—such as pregnant women or those with immune disorders—doctors may recommend varicella-zoster immune globulin (VZIG) for protection. 

Everyday prevention tips: 
Avoid close contact with infected people, wash hands often, and avoid scratching blisters to prevent spreading the virus. 

Vaccination has transformed chickenpox from a nearly universal childhood illness into a largely preventable one. Widespread immunization has drastically reduced infections, hospital stays, and deaths, and provides herd immunity—protecting people who cannot be vaccinated. 

Still, outbreaks can occur where vaccination rates are low. Expanding access to vaccines and increasing public awareness are crucial steps toward making chickenpox a disease of the past worldwide. 

Chickenpox is a preventable illness that used to be a childhood rite of passage but is now easily avoided through vaccination. For most people, it causes mild symptoms, but it can be dangerous for adults and vulnerable individuals. Getting vaccinated, recognizing early symptoms, and practicing good hygiene help protect everyone from infection. 

With continued global vaccination efforts, chickenpox can one day be eliminated—creating a healthier, safer future for all. 

1. Marin M, Güris D, Chaves SS, Schmid S, Seward JF. Prevention of varicella: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2007;56(RR-4):1-40. 

2. Heininger U, Seward JF. Varicella. Lancet. 2006;368(9544):1365-1376. 

3. Centers for Disease Control and Prevention. Varicella (Chickenpox). Epidemiology and Prevention of Vaccine-Preventable Diseases. 13th ed. Washington D.C.: Public Health Foundation; 2015. 

4. Gershon AA, Breuer J, Cohen JI, et al. Varicella zoster virus infection. Nat Rev Dis Primers. 2015;1:15016. 

5. World Health Organization. Varicella and herpes zoster vaccines: WHO position paper, June 2014. Wkly Epidemiol Rec. 2014;89(25):265-287. 

6. Sauerbrei A, Wutzler P. The congenital varicella syndrome. J Perinatol. 2000;20(8 Pt 1):548-554.