Varicella-zoster virus infection

Varicella-zoster virus infection causes chickenpox with mild fever and a maculopapular rash developing into superficial vesicles located mainly on the trunk. Vesicles can be seen in various stages of development. Herpes zoster occurs in patients previously infected with the chickenpox virus.

CASES/YEAR
1,000,000 (US); 154,000,000 (Global)
CATEGORY
Childhood Infections
AGENT TYPE
Viruses
OTHER NAMES
VZV; Chickenpox; Shingles;
ACUITY
Acute-Moderate
INCUBATION
10-21 days; usually 14-16 days; [CCDM]
INITIAL SYMPTOMS
Chickenpox: mild fever and a maculopapular rash developing into superficial vesicles located mainly on the trunk; Vesicles can be seen in various stages of development; [PPID, p. 816]
PRECAUTIONS
Standard when localized in patient with intact immune system with lesions that can be contained/covered; Airborne and Contact when disseminated disease in any patient or localized disease in immunocompromised patient until disseminated infection ruled out. [CDC 2007 Guideline for Isolation Precautions] Chickenpox patients are contagious beginning about 2 days prior to onset of the rash until all vesicles have crusted (usually about 5 days after onset of the rash). [CCDM, p. 670]
COMMENTS
FINDINGS:
The stages of the rash are maculopapular (few hours), vesicular and pustular (3-4 days), and crusted (about 5 days after onset of the rash). [The vesicle looks like a teardrop on a red base or a "dew drop on a rose petal."]. Unlike smallpox vesicles, they collapse when punctured. Complications of chickenpox include pneumonia, encephalitis, and bleeding. Herpes zoster occurs in patients previously infected with the chickenpox virus. The reactivation of the dormant varicella virus occurs in the dorsal root ganglion. Some patients develop permanent pain (postherpetic neuralgia) in the affected dermatome. [CCDM, p. 669-70] The lesions appear as successive crops over 2 -4 days so that all stages of development (papules, vesicles, pustules, and scabs) are visible. Lesions are usually about 5 mm in diameter, but may be as large as 13 mm. Varicella pneumonitis occurs in about 1 in 400 adult cases. [PPID, p. 1851-2] In varicella-zoster myelitis from shingles, patients may have weakness in the myotomes corresponding with the affected dermatomes. [PPID, p. 1238] Vesicles in the mouth can cause painful swallowing. Complications include cellulitis, pneumonia, hepatitis, and postinfectious cerebellar ataxia (occurs in 1/4000), and Reye's syndrome (coma). [Merck Manual, p. 1619] Herpes zoster may cause conjunctivitis, keratitis, uveitis, and, rarely, cranial nerve palsies. Blindness is a complication of herpes zoster ophthalmicus. Symptoms of encephalitis include seizures, headache, and vomiting. [Guerrant, p. 994, 360] WBC count varies; marked leukocytosis suggests secondary infection. [5MCC-2020] In primary or systemic VZV infections, elevation of transaminases is typical. Thrombocytopenia occurs in severe disease. [Wallach, p. 1191] Skin lesions may be hemorrhagic in patients with immunosuppression, e.g., leukemia. [ABX Guide] See "Keratitis."

PREVENTION:
"Exposed susceptibles eligible for immunization should receive vaccine as soon as possible after exposure to prevent disease and transmission with potential occurrence of an outbreak." Varicella-zoster immune globulin is available in several countries for immunodeficient patients and pregnant women. [CCDM, p. 674] VariZIG is administered only to those at high risk. [ABX Guide] "Only HCP with evidence of immunity to varicella should care for patients who have confirmed or suspected varicella or HZ. . . . Unvaccinated HCP who have no other evidence of immunity who are exposed to VZV (varicella, disseminated HZ, and uncovered lesions of a localized HZ) are potentially infective from days 8-21 after exposure and should be furloughed during this period. They should receive postexposure vaccination as soon as possible. Vaccination within 3-5 days of exposure to rash might modify the disease if infection occurred." (See recommendations for HCP at risk for severe disease for whom varicella vaccination is contraindicated.) A vaccine to prevent HZ [herpes zoster] is available and recommended for all persons aged > or = 60 years without contraindications to vaccination." [ACIP, 2011]
DIAGNOSTIC
Typical skin eruption; If not sure, can confirm with Tzanck smear, culture, immunofluorescence stains, or PCR; [ABX Guide] Commercial kits to detect varicella-zoster by IgM are not recommended. [CDC Travel]
SCOPE
Global; Routine vaccinations in US since 1996; In most parts of the world, vaccination is not routine and risk of exposure is higher; [CDC Travel]
SIGNS & SYMPTOMS
  • >arthralgia
  • >fever
  • >myalgia
  • E pharyngitis
  • E rhinitis
  • E stomatitis
  • G liver function test, abnormal
  • G nausea, vomiting
  • H leukocytosis
  • H leukopenia
  • H lymphadenopathy
  • H thrombocytopenia
  • N confusion, delirium
  • N headache
  • N muscle weakness
  • N paresthesia
  • N seizure
  • N stiff neck
  • O conjunctivitis, acute
  • R chest pain
  • R cough
  • R dyspnea
  • S papules or plaques
  • S petechiae and ecchymoses
  • S pustule
  • S rash (exanthem)
  • S skin blister or vesicles
  • S ulcer of skin
  • X lung infiltrates
  • *arthritis
  • *bleeding tendency
  • *blindness
  • *cranial neuropathy
  • *encephalitis
  • *erythema nodosum
  • *glomerulonephritis
  • *hepatitis
  • *meningitis
  • *myelitis
  • *myocarditis
  • *pancreatitis
  • *paralysis
  • *pericarditis
  • *peripheral neuropathy
  • *pneumonia
  • *pneumonitis
  • *rhabdomyolysis
  • *sepsis
  • *shock
  • *stupor, coma
  • *uveitis
ANTIMICROBIC

Yes

VACCINE

Yes

ENTRY
Inhalation, Skin or Mucous Membranes (Includes Conjunctiva)
SOURCE
Person-to-Person
RESERVOIR
Human
RISK FACTORS
  • AIDS patients
  • Cancer patients
  • Care for patients (droplet/airborne)
  • Fail to complete immunizations
  • Live together in close quarters
  • Travel to endemic area
TREATMENT
"Treatment with antivirals is not routinely recommended for otherwise healthy children with varicella." [CDC Travel, p. 370] Because of Reye's syndrome risk, aspirin is contraindicated. Ophthalmologic consultation is recommended if herpes zoster ophthalmicus is suspected. [PPID, p. 1852-3] Herpes zoster vaccine is recommended for people >50 years to prevent shingles. [5MCC-2020]
DRUG LINK
Merck Manual: Herpes Zoster
REFERENCES FOR CASES/YEAR
1. (US) 216,511 cases reported in 2012; [Harrison ID, p. 49] About 1 million cases of herpes zoster in US annually; [PPID, p. 1849]
2. (Global) Before the vaccine was available, more than 95% of children in temperate climates were infected with varicella. About 50% of people infected with VZV will have zoster if they live to age 85; [Cecil, p. 2192] About 1 million cases of herpes zoster in US annually; Incidence of chickenpox = annual birth rate before vaccine introduced; [PPID, p. 1849] Guesstimate: Assume 90% of population not immunized; then cases per year = 90% X 134 million (annual births in world) = 121 million; Calculate: Zoster incidence in US estimated at 1 million or 1/4 of births; 1/4 of 134 million = 33.5 million; 121 + 33.5 = 154.5;