Medically Reviewed By William C. Lloyd III, MD, FACS
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What is chickenpox?

Chickenpox is an extremely contagious infection caused by the varicella-zoster virus. The most commonly recognized symptom of chickenpox is the development of multiple itchy blisters all over the body. The blisters typically start on the face and trunk before spreading. The fluid-filled blisters eventually break open, the fluid leaks out, and scabs form. Flu-like symptoms such as fever, headache, cough, sneezing, and a general feeling of being ill can accompany the blisters.

Before a vaccination for chickenpox was available, it was considered a rite of passage from childhood into adolescence; most school-age children caught it eventually. Once a person has had chickenpox, it is unlikely that it will recur. Because a vaccine is now available, children no longer need to risk the sometimes serious complications that can occur from chickenpox.

Chickenpox can be spread directly through person-to-person contact and indirectly through the air when an infected person coughs or sneezes. Infectious droplets can also enter the air and spread from the skin rash. Symptoms commonly develop within 10 to 21 days of exposure, although the disease becomes contagious a day or two before the blisters appear and remains so until they have scabbed over.
Fortunately, the illness usually resolves on its own within a week to 10 days.

Treatment options include anti-itch creams, pain-relieving creams, and antihistamines. Analgesics such as acetaminophen (Tylenol) can help with discomfort. Aspirin should not be used in children because of the potential risk of developing Reye’s syndrome, which can be life threatening. Serious infections and complications can occur and are most common in infants, adolescents, adults, and people whose immune systems are weakened, such as those who have AIDS, are undergoing cancer treatment, or have had an organ transplant. Some elderly individuals, even those who previously had chickenpox as a child, are at risk for reinfection and a far more serious bout of the disease.

Rarely, the viral chickenpox infection can spread to other areas of the body, such as the brain or lungs, resulting in more severe illness and complications. It is also possible to develop secondary bacterial infections during chickenpox. These can affect the skin, lungs, blood, joints, and other areas of the body. Seek immediate medical care (call 911) for serious symptoms, such as high fever, confusion, lethargy, loss of consciousness, rapid breathing or shortness of breath, rapid heart rate, seizure, severe headache, severe vomiting or diarrhea, or reduced urine production.

Seek prompt medical care if your symptoms recur, are persistent, or otherwise cause you concern. Women who are pregnant and anyone with a weakened immune system should also seek care promptly. Newborn infants should also receive prompt care.

What are the symptoms of chickenpox?

Flu-like symptoms such as fever, headache, coughing, sneezing, and a general feeling of being ill may occur prior to the development of the hallmark itchy red blisters of chickenpox. Symptoms can vary in intensity among individuals.

Some people with chickenpox experience a mild course, developing only a small number of blisters and having few, if any, other symptoms. This is particularly true of those who get the infection despite having been vaccinated, which is uncommon but possible. Others experience more extensive blistering and flu-like symptoms.

Common symptoms of chickenpox

Aside from blisters, many symptoms of chickenpox resemble those of cold or flu. Common symptoms of chickenpox include:

Serious symptoms that might indicate a life-threatening condition

In some people, the varicella-zoster virus can spread to other areas of the body, such as the brain or lungs. Others may develop secondary infections while they have chickenpox, which can affect the skin, lungs, blood, joints, and other areas of the body. Rarely, serious dehydration can result from chickenpox, especially when it is accompanied by diarrhea. Infections of the lung and brain, secondary infections, and severe dehydration can develop into life-threatening situations. Seek immediate medical care (call 911) if you, or someone you are with, have any of these life-threatening symptoms including:

  • Change in level of consciousness or alertness, such as passing out or unresponsiveness

  • Change in mental status or sudden behavior change, such as confusion, delirium, lethargy, hallucinations and delusions

  • Garbled or slurred speech or inability to speak

  • High fever (higher than 101 degrees Fahrenheit)

  • Not producing any urine, or an infant who does not produce the usual amount of wet diapers

  • Respiratory or breathing problems, such as shortness of breath, difficulty breathing, labored breathing, wheezing, not breathing, or choking

  • Seizure

  • Severe dizziness or sudden loss of balance

  • Severe headache

What causes chickenpox?

Chickenpox is a highly contagious infection caused by the varicella-zoster virus. It can be spread by direct contact or through the air. Because chickenpox is often contagious before the telltale blisters appear and can be spread without direct contact, it is difficult to avoid exposure to it.

Chickenpox occurs most frequently in children, but is not as common as it once was because of the development of a safe vaccine. Some adults may have evaded chickenpox as a child and acquire the infection later in life. They may have a serious bout of the disease.

What are the risk factors for chickenpox?

A number of factors increase the risk of developing chickenpox. Not all people with risk factors will get chickenpox. Risk factors for chickenpox include:

  • Attendance or work in a daycare or school setting
  • Close contact with an infected person
  • Lack of vaccination against the disease
  • No previous chickenpox exposure
  • Young age

Reducing your risk of chickenpox

You can lower your risk of developing chickenpox by:

  • Avoiding contact with people who are infected
  • Getting vaccinated against varicella-zoster virus
  • Washing your hands well with soap and water after having contact with an infected person

How is chickenpox treated?

The best way to treat chickenpox is to avoid getting it in the first place. A safe and effective vaccine is available against the varicella-zoster virus. Varicella-zoster vaccination can be given by itself or in combination with the measles-mumps-rubella vaccination, also known as the MMR.

Immune globulin injections or antiviral medication may be given to exposed susceptible immunocompromised or pregnant individuals.

For those who develop chickenpox, the goal of treatment is to provide symptom relief and prevent complications. Antiviral medications can be given to decrease the risk of complications, especially in those at highest risk, such as infants, adolescents, and people whose immune systems are weakened. To be most effective, antiviral treatments need to be started early in the course of the infection.

Antiviral medications that are used to treat chickenpox include:

  • Acyclovir (Zovirax)

  • Valacyclovir (Valtrex)

Occasionally, the sores caused by chickenpox can get infected by bacteria; this is called a secondary infection. Secondary infections can also occur in the lungs, blood, joints, and other areas of the body. Antibiotics are used in the treatment of secondary bacterial infections. In these cases, the choice of antibiotic depends upon the type and severity of the infections.

What you can do to improve the symptoms of your chickenpox

In addition to following your health care provider’s instructions and taking all medications exactly as prescribed, you can help alleviate your symptoms and decrease your risk of complications by:

  • Applying anti-itch lotions, such as calamine

  • Avoiding scratching at the blisters and sores

  • Avoiding sunlight and sunburn

  • Clipping fingernails to reduce injury from scratching

  • Ensuring adequate hydration by drinking plenty of water

  • Getting plenty of rest

  • Putting mittens or socks on children’s hands to discourage scratching

  • Taking lukewarm oatmeal baths to soothe the skin

  • Taking oral antihistamine medications

  • Taking over-the-counter pain relief medications such as acetaminophen (Tylenol) or ibuprofen (Advil, Motrin). Aspirin use should be avoided in children.

  • Washing your hands frequently with soap and water

  • Wearing clothes that are clean, dry and loose-fitting

What are the potential complications of chickenpox?

In some people, especially infants, adolescents, adults, and people whose immune systems are weakened, complications of chickenpox can be severe, even life threatening. You can help minimize your risk of serious complications by following the treatment plan you and your health care professional design specifically for you. Complications of chickenpox can include:

  • Cerebellar ataxia (inflammation of a part of the brain that results in problems coordinating muscle movements, which typically resolves on its own)

  • Dehydration (loss of body fluids and electrolytes, which, left untreated, can be life threatening)

  • Encephalitis (inflammation and swelling of the brain due to a viral infection or other causes)

  • Pneumonia

  • Pregnancy complications, such as miscarriage or spread to the fetus

  • Scars

  • Secondary infections of the blisters or sores

  • Sepsis (life-threatening bacterial blood infection)

  • Septic arthritis (infectious arthritis)

  • Shingles (reactivation of the varicella-zoster virus, which remains in the body in an inactive state following chickenpox)

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jan 9
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
  1. Chickenpox (varicella). Centers for Disease Control and Prevention.
  2. Chickenpox. PubMed Health, a service of the NLM from the NIH.
  3. Bope ET, Kellerman RD (Eds.) Conn’s Current Therapy. Philadelphia: Saunders, 2012.