Chickenpox, also known as varicella, is a highly contagious infection caused by the varicella zoster virus (VZV). It causes an itchy, blister-like rash. Most people recover within 1 to 2 weeks, but some develop complications.

Chickenpox is a viral illness that causes a blister-like rash. The rash first appears on the face and trunk and then spreads throughout the body.

Among people who are not vaccinated, chickenpox is extremely contagious. Although chickenpox is not a life threatening illness, it can sometimes cause complications.

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The main symptom of chickenpox is a distinctive, itchy rash. One person can have up to 500 blisters during a chickenpox infection.

However, the symptoms tend to be absent or mild in people who have received a vaccine. This is known as breakthrough chickenpox.

Chickenpox develops in stages. Before the rash appears, a person may experience the following for 1 to 2 days:

  • fatigue
  • fever
  • general feeling of being unwell (malaise)
  • loss of appetite
  • muscle or joint aches
  • headache

After these symptoms, spots will develop, possibly beginning on the back, chest, or face. The rash may spread to the entire body, including the inside of the mouth, genitals, or eyelids.

The spots will be red in those with lighter skin tones, while in people with darker skin tones, they may be the same color as the surrounding skin.

Next, the spots will fill with fluid and resemble blisters. They are often intensely itchy and may burst or scab over. All of the spots will usually turn into scabs after around 1 week.

Symptoms in adults

Although chickenpox typically affects children, anyone who has not had the infection before can get it, including adults.

The symptoms in adults may be similar to those in children, but they are often more severe. They may feel worse, have symptoms that last longer, and they have a higher risk of complications, including pneumonia.

Experts recommend treating adults who have chickenpox with antiviral drugs within 24 to 48 hours of the rash developing.

The cause of chickenpox is the varicella-zoster virus (VZV), which belongs to the same family of viruses as the herpes simplex viruses.

VZV transmits when people inhale droplets from coughs and sneezes. It can also occur if someone touches the fluid that the blisters contain.

Chickenpox is highly contagious. According to the Centers for Disease Control and Prevention (CDC), up to 90% of people who come into close contact with someone who has chickenpox will get the infection if they do not have existing immunity.

A doctor or nurse will know whether a child or adult has chickenpox by recognizing a person’s telltale rash and asking a few questions about their symptoms.

When a person is not vaccinated and is not sure whether they have had chickenpox as a child, they may be able to get a laboratory test to determine whether they have had the virus in the past.

If a person has had chickenpox before, a doctor may suspect shingles. Shingles can occur when VZV lies dormant in the body and reactivates later in life.

There is no cure for chickenpox, but for most children, it resolves on its own within a week or two.

If a person is not at high risk for complications, doctors may recommend ways to reduce the symptoms and prevent transmission to others. They may suggest:

Acetaminophen

Acetaminophen (Tylenol) may help reduce high fever and pain when a person has chickenpox. However, it is important to follow the dosage instructions, especially for children.

Do not give ibuprofen to people with chickenpox, as this may lead to serious bacterial infections. Children should also never have aspirin, as it can lead to a life threatening complication known as Reye’s syndrome.

Remedies for itching

The following may help to reduce itchiness in people with chickenpox:

For blisters inside the mouth, it may help to suck on popsicles or ice. Some may find it helpful to limit foods that could irritate the blisters, such as spicy foods.

Itch prevention

Scratching chickenpox blisters can lead to scarring. If a person’s hands have fluid on them from inside the blister, they may also transfer the VZV virus to others.

Prevent scratching by:

  • keeping nails trimmed short
  • wearing loose clothing that covers the skin
  • wearing cotton gloves or mittens at night to prevent scratching

Wash the hands for 20 seconds with soap and water after touching chickenpox blisters.

Antiviral drugs

People who are at a higher risk of complications from chickenpox may need antiviral drugs. These drugs do not eliminate the infection, but they can make the condition less severe or shorten its duration.

The CDC recommends that the following groups begin antiviral drugs as soon as they can after blisters appear, ideally in the first 24 hours:

  • anyone over the age of 12 who has never had chickenpox
  • people with weakened immune systems
  • those with chronic lung or skin conditions
  • people taking long-term steroid or salicylate therapy, which includes long-term aspirin therapy
  • pregnant people

People in these groups should contact a doctor as soon as they get symptoms. They should also contact a doctor if a baby under the age of 1 develops chickenpox.

The best way to prevent chickenpox is by getting the chickenpox vaccine.

In the United States, the chickenpox vaccine has reduced chickenpox infections by 97% since 1995, dramatically reducing hospitalizations and deaths.

There are two types of the VZV vaccine:

  • Varivax: This vaccine is just for chickenpox. Children get two shots, receiving the first dose between 12 and 15 months of age and a second dose between 4 and 6 years. Anyone 12 months and older, including adolescents and adults, can get this vaccine.
  • ProQuad: This is a combination vaccine that also contains vaccines for measles, mumps, and rubella. Healthcare professionals call it the MMRV vaccine. Children get this vaccine on the same schedule as Varivax, but it can only be given to children between 12 months and 12 years old.

If they are old enough, people can get the Varivax shot at any time, but people can also get it after they have had exposure to someone with chickenpox.

Doing this may prevent the condition or make it less severe in those who have never had chickenpox or a vaccination in the past.

Some people may not be eligible to have a vaccine, including those who:

  • have HIV
  • have cancer, or who are undergoing cancer treatment
  • have recently had a blood transfusion or received other blood products
  • are or could be pregnant

Other ways to prevent chickenpox transmission include:

  • avoiding contact with people who have chickenpox
  • practicing hand hygiene
  • not sharing personal objects, such as cutlery or towels, with others
  • isolating household members who have chickenpox, if others in the household have not had it
  • disinfecting surfaces the person has touched

People who had chickenpox as children will not get the disease again because they will develop immunity to the virus.

Rarely, people develop severe chickenpox symptoms or complications. These can include:

These complications can become life threatening in some cases.

Complications in pregnancy

People who are pregnant have a slightly higher risk of developing pneumonia from chickenpox. There is also a danger of passing the infection to the fetus.

If infection occurs during the first 20 weeks of pregnancy, there is a higher risk of congenital varicella syndrome. This can cause scarring in the fetus, as well as eye problems, brain drainage, and shortened arms or legs.

If the infection happens later in pregnancy, the virus can transmit directly to the fetus and the baby may have VZV from birth.

If a person becomes exposed to varicella during pregnancy, it is important to talk to a doctor right away.

Anyone in an at-risk group for chickenpox complications should contact a doctor if they develop symptoms. Call ahead before visiting a doctor or medical facility in person.

Seek immediate medical attention if someone develops:

  • a fever that lasts more than 4 days
  • a fever that rises above 102°F (38.9°C)
  • areas of skin that are inflamed, warm, or tender, or begin oozing pus
  • a rash that bleeds or looks bruised
  • confusion
  • difficulty waking up
  • difficulty walking
  • difficulty breathing
  • a severe cough
  • a stiff neck
  • frequent vomiting
  • severe pain in the abdomen

Chickenpox is a contagious illness caused by the varicella-zoster virus (VZV) that causes a highly itchy rash.

Historically, most people got chickenpox in childhood, but today, the U.S. has a vaccination program that has reduced infections by 97%.

There are two types of chickenpox vaccines, one of which people can get at any time if they are 12 months or older. Breakthrough infections are still possible, though.