Varicella (chickenpox) is caused by the varicella-zoster virus, which falls under the herpes virus category.1 After primary infection, the varicella-zoster virus remains in the sensory nerve ganglia as a dormant infection. The incubation period of varicella is 14 to 16 days after varicella rash or herpes-zoster rash exposure. Mainly in adults, mild fever and malaise can occur 1 to 2 days before rash onset; in children, rash is commonly the first indication of the disease.
Varicella is highly contagious, and spreads when an infected patient coughs or sneezes, or when the virus is touched or inhaled via varicella lesions. Patients with varicella are contagious 1 to 2 days before rash onset until the lesions crust. Varicella is largely mild in healthy children, but there is higher risk for severe disease and complications in adults with varicella. The most common complications in children are bacterial infections of the skin and soft tissues, and, in adults, pneumonia. Recovery from varicella typically offers patients life-long immunity, and recurrence of varicella is uncommon in otherwise healthy people.
Immunocompromised patients with varicella are at risk for visceral dissemination, which can lead to pneumonia, hepatitis, encephalitis, and disseminated intravascular coagulopathy.2 These patients can have more lesions and remain ill longer than immunocompetent patients with varicella.
Children with human immunodeficiency virus (HIV) infection may have new lesions for several weeks or months. Typical maculopapular vesicular lesions may develop into nonhealing ulcers that become necrotic, crusted, and hyperkeratotic. This is more likely to occur in children with HIV who have low CD4 counts. Most adults with HIV have already had varicella, so the disease is uncommon in this population.
Pregnant women with varicella are at high risk for pneumonia, and may die of varicella in certain cases. If varicella is contracted in the first or early second trimester, the baby has a small risk for congenital varicella syndrome, and may have skin scarring, low birth weight, and limb, brain, or eye abnormalities. If a pregnant woman develops the varicella rash from 5 days before or to 2 days after delivery, the baby is at risk for neonatal varicella.
Signs and Symptoms
Illness from varicella lasts approximately 5 to 10 days.3 The classic symptoms are an itchy rash with fluid-filled blisters that eventually crust. The rash may first appear on the face, chest, and back, and then spread to other parts of the body. It takes approximately 1 week for all the blisters to crust. Common symptoms that may appear 1 to 2 days before rash include high fever, tiredness, loss of appetite, and headache. Some people who have been vaccinated against chickenpox can still get the disease, but their symptoms are often milder.
Vaccination is the best way to protect patients from contracting varicella.4 The Centers for Disease Control and Prevention recommends that children receive the first dose of the varicella vaccine at ages 12 through 15 months, and the second dose at ages 4 through 6 years. People aged ≥13 years who have not had varicella or have not been vaccinated should receive 2 doses of the vaccine ≥28 days apart. Receiving 2 doses of the vaccine helps prevent severe disease, complications, and death.
In addition, people who receive the vaccine help protect others in their community from varicella, which is important for pregnant women and people with weakened immune systems who cannot receive the vaccine. The cost of the vaccine is covered by most health insurance plans. The Vaccines for Children Program may be able to help patients who do not have health insurance, or have insurance that does not cover vaccines, gain access to the vaccine.
- Centers for Disease Control and Prevention. Chickenpox (varicella): clinical overview. www.cdc.gov/chickenpox/hcp/clinical-overview.html. Updated August 22, 2013. Accessed January 19, 2016.
- Centers for Disease Control and Prevention. Chickenpox (varicella): people at high risk for complications. www.cdc.gov/chickenpox/hcp/high-risk.html. Updated September 10, 2014. Accessed January 19, 2016.
- Centers for Disease Control and Prevention. Chickenpox (varicella): signs & symptoms. www.cdc.gov/chickenpox/about/symptoms.html. Updated November 16, 2011. Accessed January 19, 2016.
- Centers for Disease Control and Prevention. Chickenpox can be serious. www.cdc.gov/features/preventchickenpox/. Updated August 21, 2015. Accessed January 19, 2016.