Chickenpox (varicella-zoster) is a highly contagious virus that causes flu-like symptoms and an itchy rash that turns into blisters that eventually crust over. You can catch chickenpox through direct contact with an infected person or by breathing in droplets from their sneezes or coughs. Most cases are mild, but newborns, pregnant people, and people with weakened immune systems may experience more severe illness.
The varicella vaccine is highly effective, making chickenpox less common than it once was. After you get chickenpox, the virus stays in your body and can cause shingles, a painful rash, later in life. A shingles vaccine is available for adults over 50 or those over 19 with a weakened immune system.
Chickenpox symptoms progress through several stages, typically developing over 4-7 days.
Early (Prodromal) Symptoms
You may experience flu-like symptoms within a week of exposure, about 1-2 days before the characteristic chickenpox rash appears. Early symptoms last about 5-7 days and might include:
- Fatigue
- Fever
- Headache
- Loss of appetite
- Runny nose
- Sore throat
- Malaise (generally not feeling well)
- Abdominal pain (less common)
Rash and Blister Stage
The hallmark chickenpox rash typically appears 14-16 days after exposure to the virus and progresses through the following stages:
- Red bumps (papules): About 250-500 small, extremely itchy red spots or bumps form.
- Blisters (vesicles): The red, itchy bumps fill with fluid, becoming blisters of various sizes. The blisters appear in waves or stages, with some drying up and others forming simultaneously over 3-7 days.
- Scabbing: The blisters eventually break open and crust, causing scabs that eventually fall off. It takes about one week for all blisters to scab.
The rash usually starts on the chest, back, or face and spreads to the scalp, arms, and legs. A smaller portion may affect the palms of the hands and soles of the feet, inside the mouth or throat, the eyes, and the genital or bottom area.
The varicella-zoster virus (VZV) causes chickenpox. You can catch VZV by touching an infected person’s rash, breathing in respiratory droplets from their coughs or sneezes, or touching surfaces contaminated with the virus and then touching your mouth or eyes. Chickenpox is contagious until about five days after the rash appears.
After your body fights off the infection, the virus stays hidden in your nerve cells. It can reactivate later in life as shingles, a painful rash that typically develops on one side of the body.
Healthcare providers recommend the shingles vaccine Shingrix (recombinant zoster vaccine) for people over 50. It’s given in two doses, 2-6 months apart, and is 80-90% effective at preventing shingles.
Risk Factors
If you are not immune to chickenpox, there is a 90% chance of getting it when you are in close contact with someone who has it. The following factors increase the risk of getting severely ill with chickenpox:
- Age: Infants less than one and adults over 20
- Pregnancy: Can cause complications for the pregnant person or the baby
- Weakened immune system: People with a weakened immune system due to illness or medications
A healthcare provider typically diagnoses chickenpox based on your symptoms and a physical exam. This is usually enough, especially if the classic red, itchy rash and fluid-filled blisters are present. If there is any doubt, your provider may perform the following tests to confirm the diagnosis:
- Direct fluorescent antibody (DFA) test: Involves a swab sample and examining it in a lab using fluorescent dyes to make the virus light up under a microscope (often replaces the previously-used Tzanck test, which involves scraping a sample from a blister)
- Immunoglobulin G (IgG) blood test: Detects antibodies to see if you’ve had chickenpox before and are now immune
- Immunoglobulin M (IgM) blood test: Detects antibodies from a current or recent infection
- Polymerase chain reaction (PCR) test: Detects tiny pieces of the varicella-zoster virus’s genetic material in blood or blister fluid, the most accurate method for detecting chickenpox
- Vesicle fluid culture: Sending fluid from blisters to a lab to see if the virus will grow (or “culture”) over time
There is no cure for chickenpox, so treatment aims to reduce discomfort, prevent complications, and speed up recovery.
Symptom Relief
You can typically soothe your skin and reduce itching with these strategies:
- Take antihistamines like Benadryl (diphenhydramine)
- Avoid scratching and trim your fingernails to help avoid skin infections if you do scratch
- Try baking soda, cornstarch, or oatmeal baths or pastes
- Apply calamine lotion or hydrocortisone 1% cream
- Use cold compresses or take lukewarm baths
- Try to avoid excess heat or humidity
- Take Tylenol (acetaminophen) for fever and pain (avoid Motrin, Advil (ibuprofen) and aspirin for children with chickenpox)
Prescription Medications
For severe cases or people at higher risk, healthcare providers may prescribe antivirals like Zovirax (Acyclovir), Valtrex (Valacyclovir), or Famvir (Famciclovir) to help shorten and decrease chickenpox symptoms.
Antivirals work best if taken within 24 hours of the rash starting.
The best way to prevent chickenpox is to get the varicella vaccine if you have not had the virus. Two complete doses help your body fight off chickenpox and lower the risk of spreading it to others. Since the vaccination program began in the United States, chickenpox cases decreased by 97%, and complications are now rare.
While the varicella vaccine is highly effective, you can still get a mild chickenpox, even if you have the vaccine. The rash is typically minor, with no blisters. However, you are still contagious until you have no new red spots for 24 hours.
Here are some precautions to avoid catching or spreading the virus when caring for someone with chickenpox:
- Practice good handwashing
- Don’t touch the rash or blisters without gloves
- Disinfect surfaces that you commonly touch
- Avoid sharing personal items like towels, utensils, and bedding
- Wear a mask (e.g., an N95) if the person has coughing or sneezing symptoms
While it’s not common, chickenpox can lead to complications, especially in high-risk individuals like newborns, pregnant people, or those with weakened immune systems. These complications can include:
- Arthritis: This condition causes joint inflammation (swelling and irritation) and pain.
- Bacterial skin infections: Scratching chickenpox blisters can allow bacteria like staph or strep to enter the skin.
- Brain problems: Rare complications include cerebellar ataxia (trouble with coordination), encephalitis (brain swelling), or meningitis (infection of membranes surrounding the brain and spine).
- Dehydration: If mouth sores make drinking difficult, you might not consume enough fluids.
- Glomerulonephritis: This inflammation affects tiny filters (glomeruli) in the kidneys.
- Hepatitis: Hepatitis includes any condition that causes liver inflammation.
- Pneumonia: This lung infection causes symptoms like shortness of breath, cough, fever, chest pain, and fatigue.
- Reye’s syndrome: This rare condition causes swelling in the liver and brain. Giving aspirin to a child with chickenpox can trigger this condition.
- Sepsis: This life-threatening condition causes a dangerous whole-body immune reaction (inflammatory response).
- Thrombocytopenia: Low platelets reduce blood clotting ability, making you bruise or bleed easily.
Complications During Pregnancy
Chickenpox during pregnancy can lead to various complications. For example:
- If a pregnant person gets chickenpox, especially in their third trimester, they are at higher risk of viral pneumonia.
- If chickenpox occurs in the first or early second trimester, it can harm the baby, possibly causing scars, underdeveloped limbs, or brain issues.
- Later in pregnancy, the baby might develop severe chickenpox after birth, which can be life-threatening.
The varicella-zoster virus causes chickenpox, a highly contagious disease. The varicella vaccine offers strong protection against chickenpox. However, if you are not immune, you can catch it through direct contact with an infected person or by breathing in droplets when they cough or sneeze. Common symptoms include fever, tiredness, and an itchy rash that turns into blisters and crusts.
Chickenpox often improves with home care, but severe cases or people with weak immune systems may need antiviral medication. Contact a healthcare provider if your rash spreads to your eyes, causes severe pain, or if you’re at high risk for complications.