Varicella (Chickenpox)

Chickenpox (Varicella)

Clinical presentation, diagnostic tests, differential diagnosis, and treatments


  • Varicella (chickenpox) is a viral disease that is highly contagious
  • Caused by the Varicella-zoster virus (VZV)
  • Transmitted by droplets & by direct contact
  • Incubation period averages 14-16 days
  • Person is contagious 1-2 days prior to rash & until all lesions have crusted (dried crusts are not infectious)
  • Chickenpox can be spread by people with herpes zoster
  • Prodrome stage- child may have low grade temperature, fatigue, anorexia, respiratory infection for 24-48 hours prior to getting skin lesions
  • Lesions can may be in various stages at one time & often appear in crops
  • Lesions generally start as a few spots on face & trunk & progress up to 200-400 lesions
  • Lesions may be found on the scalp, mucous membranes & conjunctiva
  • Giving vaccine within 72 hours of exposure will prevent or reduce the severity of the disease
  • CDC recommends 2 doses of the vaccine for children 12 months to 12 years given at least 3 months apart
  • If a pregnant women gets chickenpox during the first 20 weeks of pregnancy, the baby may get congenital varicella syndrome
  • Congenital varicella syndrome may cause low birth weight, scars on skin, and problems affecting arms, legs, brain, and eyes
  • If a pregnant women gets chickenpox during the first few days prior to her delivery, the baby may be born with a life-threatening infection
  • If a pregnant women is exposed to chickenpox, she may be treated with a immune globulin that can reduce the severity or prevent chickenpox
  • CDC recommends waiting 4 weeks after vaccination before trying to conceive

Clinical Presentation

  • In children there is usually no prodrome. Most children have mild prodrome with slight malaise and low-grade fever.  Adolescents and adults have more severe prodrome.
  • A few hours or days after the prodrome, a rash on scalp, neck, upper trunk emerges.
  • Exanthema occurs in stages: begins as macules, than turns into papules, and then into vesicles all within 12-24 hrs.
  • When vesicles begin to resolve, a crust will develop.
  • The rash will spread centrifugally (away from center)
  • Lesions may be present on mucous membranes of mouth, conjunctivae, esophagus, trachea, rectum, and vagina.
  • Pruritus
  • Palms and soles do not have lesions
  • lesions appear in crops or groups over several days
  • lesions are superficial, thin-walled, and easily ruptures

Diagnostic Tests

  • Usually none needed
  • Verus can be isolated from scrapings of the vesicle base during first 3 days of eruption: tissue cultures, DFA,, or Tzanck smears
  • Acute and convalescent titers by standard serologic assays can confirm diagnosis (increase in serum varicella IgG antibodies)

Differential Diagnosis

  • Scabies or insect bites
  • Herpes simplex
  • Folliculitis
  • Impetigo
  • Contact Dermatitis
  • Coxsackievirus (vesicles do not usually crust)
  • Echovirus (vesicles do not usually crust)
  • Drug eruptions
  • Secondary Syphilis
  • Smallpox (no pruritus) (lesions are on palms, soles, face and extremities)


  • Symptomatic treatment to alleviate itching
  • baking soda/Aveeno oatmeal bath
  • Calamine lotion to skin
  • Antihistamines for pruritus: Benadryl > 10kg, 5mg/kg/day in 3 or 4 doses or Atarax > 6 years old, 50mg/day in divided doses
  • Acetaminophen as indicated for temperature elevation, 10-15 mg/kg q 4 hrs.  Do not use aspirin
  • Oral Lesions: warm saline or hydrogen peroxide mouth rinses
  • Genital lesions: warm saline or hydrogen peroxide compresses
  • Infected lesions: 1 or 2 lesions- wash lesions well with gentle soap and water & apply Neosporin ointment QID or Bacitracin ointment QID
  • Zovirax (acyclovir): Infectious disease experts do not recommend use in a healthy child, but may be given within 24 hrs of onset of rash because it will result in a milder illness.  Other indications for use of Zovirax (acyclovir) are: varicella in a secondary family member, child under 12 years, child with chronic disease, or child with eczema.
  • Varicella-zoster immune globulin (VZIG) should be administered within 96 hours of exposure if: the newborns mother had varicella less than 5 days prior to delivery or 48 hrs after delivery, premature infants, children with cancer or collagen-vascular disease, organ or bone marrow transplant recipients, children treated with steroids, chemotherapy, radiation, immunodeficient children, children with severe burns or eczema, and pregnant women.



Boynton, R. W., Dunn, E. S., Pulcini, J. A., St. Pierre, S. B., & Stephens, G. R. (2010). Varicella. In Manual of ambulatory pediatrics (pp. 409-414). Philadelphia: Wolters Kluwer.

Centers of Disease Control (n.d.). Chickenpox (Varicella). Retrieved 2016, from

Uphold, C. R., & Graham, M. V. (2003). Varicella. In Clinical guidelines in family practice (pp. 243-246). Gainesville, Fl: Barmarrae Books, Inc..