Chickenpox: Symptoms, Treatment, and Prevention
Also known as: Varicella, Varicella-zoster infection
What Is Chickenpox?
Chickenpox is an extremely contagious childhood viral infection caused by the varicella-zoster virus. It shows up as a characteristic skin rash that develops in several waves of blister-like lesions. According to the CDC, chickenpox caused about 4 million cases a year in the U.S. before the vaccine became widely used, and more than 90% of those cases were in children, generally before age 10. Most cases occurred in winter and spring. Before the vaccine was available, the infection reached about 90% of American children by age 10, and it was most common in the 4 to 10 year age group.
Once someone has had the illness, the virus remains dormant in the body and can reactivate later in life as shingles.
Causes and Risk Factors
Chickenpox spreads through inhaling respiratory droplets when an infected person coughs or sneezes, or through direct contact with fluid from the blisters. Contagiousness is highest 1 to 2 days before the rash appears and continues until all the lesions have crusted over, which usually takes another 5 to 7 days.
Group settings for children (daycares, schools) strongly favor its spread. Unvaccinated adults, pregnant women, and immunocompromised people face a higher risk of complications.
Symptoms
The rash typically appears 10 to 21 days after exposure. It starts as small, itchy blisters that show up in successive waves on the face, scalp, and then the rest of the body, giving the appearance of lesions at different stages. A child may develop anywhere from 250 to 500 blisters over red spots. Some children also have a fever, headache, tiredness, or loss of appetite before the rash appears.
Mild fever and often intense itching accompany the rash. The illness is usually mild and lasts about 5 to 10 days, with symptoms generally improving within a week or so.
In adults, symptoms are generally more pronounced and the risk of lung complications higher: adults are more likely than children to develop pneumonia, which is the most serious complication in this group. Other possible complications include bacterial skin infections, inflammation of the blood vessels, and swelling of the brain.
Diagnosis
Diagnosis of chickenpox is mainly clinical, based on the characteristic appearance of the skin lesions and known recent exposure. If there’s diagnostic uncertainty, particularly in adults or pregnant women, specific lab testing (serology, PCR) can be done to confirm the infection and assess risk to the fetus if applicable. Infection during the first 20 weeks of pregnancy can lead to severe birth defects, so suspected exposure in pregnancy should always be discussed with a doctor.
Available Treatments
Care for chickenpox remains mainly symptomatic:
- Acetaminophen for fever. Never give aspirin to a child with chickenpox, because it can cause a serious condition called Reye syndrome. Ibuprofen should also be avoided, as it has been associated with more severe secondary infections.
- Antiseptic skin care to prevent bacterial superinfection of the blisters
- Antihistamines for bothersome itching, such as over-the-counter oral diphenhydramine, after checking with your doctor
- Lukewarm baths with baking soda, calamine lotion, or an oatmeal bath to soothe the itching
- A specific antiviral treatment may be offered for people at risk of a severe form. Antivirals are not given to everyone, and they work best when started within the first 24 hours after the rash appears.
Complete healing generally occurs within one to two weeks, without lasting effects in most uncomplicated cases.
Prevention and Practical Tips
The varicella vaccine is part of the routine childhood immunization schedule in the U.S. The first dose is given at 12 to 15 months and the second dose at 4 to 6 years, with at least 3 months between doses.
Vaccination is also recommended for unvaccinated adolescents and adults without a history of chickenpox, particularly healthcare workers in contact with vulnerable people. People aged 13 and older who have not had chickenpox or the vaccine receive two doses at least 4 weeks apart.
Keeping fingernails clean and neatly trimmed limits scratching-related lesions and the risk of superinfection. Good hand hygiene reduces transmission within the household.
When Should You See a Doctor?
A visit is needed for persistent high fever, superinfected lesions, or in people at risk of complications (pregnant women, newborns, immunocompromised people). If in doubt, don’t hesitate to see a doctor quickly.
Sources
- MedlinePlus (NIH), U.S. National Library of Medicine chickenpox overview
- MedlinePlus Medical Encyclopedia, chickenpox symptoms, transmission, and treatment
- MedlinePlus Drug Information, varicella vaccine schedule
- American Academy of Pediatrics (HealthyChildren.org), chickenpox information for parents
- StatPearls, National Library of Medicine (NIH), varicella-zoster virus clinical review
- 25 Years of Varicella Vaccination in the United States (CDC authors, PMC/NIH), pre-vaccine U.S. burden of about 4 million cases a year, more than 90% of them in children
- Celebrating 25 Years of Varicella Vaccination Coverage for Children and Adolescents in the United States (CDC authors, PMC/NIH), pre-vaccine U.S. annual case, hospitalization, and death counts