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Is Chickenpox Contagious?

Reviewed on 12/22/2020

Chickenpox

Early symptoms of chickenpox include fever, feeling unwell (malaise), sore throat, and loss of appetite

Chickenpox is a highly contagious disease caused by the varicella-zoster virus (VZV). The varicella-zoster virus is transmitted to people who have never had chickenpox or have never been vaccinated when an infected person coughs or sneezes, releasing airborne droplets that another person may inhale. The virus can also be contracted by touching an area of chickenpox rash on an infected person or by close contact with a person who has chickenpox. 

The varicella-zoster virus also causes shingles and can be transmitted via close contact with people with shingles to others who have never had chickenpox or received the chickenpox vaccine. 

Chickenpox is contagious starting 1 to 2 days before the rash appears and until all the chickenpox lesions have scabbed over. People who are vaccinated and develop chickenpox may have lesions that do not crust, but these patients are still contagious until no new lesions have appeared for 24 hours.

What Is Chickenpox?

Chickenpox is a highly contagious viral infection that causes fever, headache, and stomach ache, followed by an itchy skin rash. The virus that causes chickenpox can linger in the body for years and later cause a painful rash called shingles.

What Are Symptoms of Chickenpox?

Early symptoms of chickenpox include:

  • Fever 
  • Feeling unwell (malaise)
  • Sore throat
  • Loss of appetite

About a day later, the characteristic rash of chickenpox appears. The rash:

  • Begins as groups of small, red bumps that are usually itchy
  • Bumps often swell with fluid and then pop
  • Tends to develop on the face, chest, back, or limbs
  • New clusters of blisters continue to appear for a few days
  • Then dries up, crusts, and scabs
  • Lasts about a week
  • Scabs take a week or two to fall off
  • Scabs may leave marks on the skin that fade over time

What Causes Chickenpox?

Chickenpox is a highly contagious disease caused by the varicella-zoster virus (VZV), which is also the same virus that causes shingles.

People at high risk for severe illness from chickenpox include:

  • Pregnant women
  • Newborns
  • People with compromised immune systems, such as patients with HIV, or those who have received an organ or bone marrow (stem cell) transplant

SLIDESHOW

Common Childhood Skin Disorders See Slideshow

How Is Chickenpox Diagnosed?

Chickenpox is usually diagnosed with a physical examination of the rash. 

If the diagnosis is uncertain, tests may include a skin scraping to detect whether the varicella-zoster virus is present in skin lesions.

What Is the Treatment for Chickenpox?

In healthy young children, treatment for chickenpox is often not needed. Most children can recover on their own without medication. Treatments are aimed at relief of symptoms and may include:

  • For fever
    • Acetaminophen (Tylenol) to treat fever 
    • Children should not be given aspirin, as it can cause a dangerous condition called Reye syndrome
  • For itching
    • Antihistamines such as diphenhydramine (Benadryl), which can make you drowsy, or loratadine (Claritin), which does not usually cause sleepiness
    • Skin treatments, such calamine lotion and oatmeal baths may help relieve itch though there is no scientific evidence these remedies work (however they are unlikely to be harmful so patients can use them if they feel them to be helpful)
    • Avoid scratching the lesions, which can cause a skin infection and may increase the chances of developing a scar

Older children, children with certain medical conditions, and adults who have not been vaccinated against the varicella-zoster virus and who develop chickenpox may have more serious symptoms. In addition to the above treatments to ease symptoms, antiviral medications may be prescribed:

What Are Complications of Chickenpox?

Complications of chickenpox are uncommon but may occur in adults and people with compromised immune systems. Complications of chickenpox may include:

How Do You Prevent Chickenpox?

The varicella vaccine prevents infection with chickenpox.

It is recommended that most children receive the first shot of the varicella vaccine when they are 12 to 15 months old, followed by a second shot between the ages of 4 to 6. Rarely, people who are vaccinated may still develop a mild case of chickenpox, though this is more likely to occur in people who do not get a second shot.

It is recommended that most adults who never had chickenpox also get the vaccine, especially those who:

  • Work in healthcare or with young children
  • Are in close contact with people who are immune compromised, such as HIV or cancer patients
  • Live or work in a college, prison, or other place where a lot of people live in close proximity
  • Travel outside the United States and Canada
  • Could get pregnant in the future 

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Reviewed on 12/22/2020
References
https://www.uptodate.com/contents/chickenpox-the-basics

https://www.uptodate.com/contents/chickenpox-prevention-and-treatment-beyond-the-basics

https://www.cdc.gov/chickenpox/index.html
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