Varicella (Chickenpox)

Varicella is a highly contagious viral infection caused by the varicella zoster virus. Most people know it as chickenpox. The infection creates an itchy rash of red spots that turn into fluid-filled blisters across the body.

Chickenpox spreads easily through the air when an infected person coughs or sneezes. You can also catch it by touching the fluid from chickenpox blisters. Most cases occur in children, but adults who never had chickenpox can get it too. Once you recover from chickenpox, the virus stays dormant in your nerve tissue and can reactivate later as shingles.

Before the chickenpox vaccine became available in 1995, nearly everyone got chickenpox during childhood. Today, vaccination has reduced cases by more than 90 percent in the United States. The vaccine helps your immune system build protection without actually getting sick from the virus.

• Itchy rash that starts as red bumps and becomes fluid-filled blisters
• Fever, usually 101 to 102 degrees Fahrenheit
• Tiredness and feeling generally unwell
• Loss of appetite
• Headache
• Rash that spreads across the face, chest, back, and eventually the whole body
• Blisters that break open and form crusts after a few days
• New spots appearing for several days while older spots crust over

Symptoms typically appear 10 to 21 days after exposure to the virus. The rash usually lasts 5 to 10 days. Most people feel itchy and uncomfortable but recover without serious problems. Adults and people with weak immune systems may experience more severe symptoms.

Chickenpox is caused by the varicella zoster virus, which spreads very easily from person to person. The virus travels through tiny droplets in the air when someone with chickenpox breathes, talks, coughs, or sneezes. You can catch chickenpox by breathing in these droplets or by touching fluid from chickenpox blisters. People with chickenpox can spread the virus from 1 to 2 days before the rash appears until all blisters have crusted over.

Anyone who has never had chickenpox or the chickenpox vaccine is at risk. Young children under age 12 make up most cases today. Adults who never had chickenpox face higher risks of serious complications. People with weakened immune systems, pregnant women, and newborns face the greatest danger from chickenpox infection. The virus spreads so easily that about 90 percent of people who live with someone who has chickenpox will catch it if they are not immune.

Doctors usually diagnose chickenpox by looking at the characteristic rash and asking about symptoms. The pattern of itchy red spots that turn into fluid-filled blisters is easy to recognize. In unclear cases, a doctor may test fluid from a blister to confirm the varicella zoster virus is present.

Blood tests can check for varicella zoster virus antibodies to determine if you have immunity. The presence of IgG antibodies means you had chickenpox in the past or received the vaccine. These antibodies provide protection against future infection. Talk to a doctor about antibody testing if you need to confirm immunity for work, school, or before pregnancy.

• Keep fingernails trimmed short to prevent scratching and skin infections
• Apply calamine lotion or colloidal oatmeal baths to soothe itching
• Use acetaminophen to reduce fever, never aspirin in children due to risk of Reye syndrome
• Drink plenty of fluids to stay hydrated
• Wear loose, soft clothing to avoid irritating the rash
• Stay home and away from others until all blisters have crusted over
• Antiviral medications like acyclovir for adults, teens, and high-risk patients if started early
• See a doctor immediately if fever lasts more than 4 days or goes above 102 degrees
• Seek care right away for signs of infection like redness, warmth, or pus around blisters
• Get medical attention for severe headache, confusion, difficulty walking, or breathing problems