Chicken Pox (Varicella)

When I was young, Chicken Pox Parties were all the rage! Yup… a party to expose kids to illness (well, I guess it’s not the only illness associated with “parties” – ex, STDs), but the possible complications of Chicken Pox that tend to could occur in older children and adults led parents to making the decision to welcome the illness while their children were younger. Fortunately, with the introduction of the successful vaccination program, the overall occurrence of primary varicella (chicken pox) has been reduced. While that is true, we still need to keep this condition on our radar. Let’s take a minute to review – Chicken Pox:

Chicken Pox: Basics

  • Chicken Pox (AKA, Primary Varicella) is caused by Varicella-Zoster Virus (VZV).
    • VZV belongs to Herpesviridae and is in the same subfamily as Herpes Simplex Virus (HSV). [Freer, 2018]
    • Has ability to induce persistent infection. [Freer, 2018]
      • VZV and HSV persist in nervous tissue.
      • The virus takes ACTIVE measures to interact with human gene expression (yup, VZV has manipulated your genes!) [Freer, 2018]
      • Reactivation occurs under conditions of cellular stress or changes in the immune status. [Freer, 2018]
        • Reactivation likely occurs more commonly than we think, as it is most often asymptomatic
        • Symptomatic reactivation = Zoster.
  • All Herpesviridae, including VZV, are very common in mammals.
    • ~80% of adults have antibodies to almost all Herpesviridae (except human herpesvirus-8, which is less prevalent). [Freer, 2018]
    • Before vaccination, Varicella was very common.
    • After vaccination, the rates in the United States have drastically reduced. [Freer, 2018]
      • ~4 million cases including 100-150 deaths/year in the early 1990’s in the USA. [Freer, 2018]
      • In 2012, after introduction of 2 dose regimen, cases have been reduced by ~93%, and deaths decreased by 90%. [Freer, 2018]
    • VZV is still present in though:
      • Not all countries vaccinate uniformly (particularly in Europe).
      • Not all people in the US get there children vaccinated (an issue for another day… but you may want to brush up on Measles and Mumps now also).

Chicken Pox: Presentation & Course

  • VZV infection is highly contagious and causes pandemics.
    • Transmitted by exposure to infectious droplets.
    • Direct contact with active skin lesions can also transmit illness.
  • Time Course: [Freer, 2018]
    • Day 0 – Infection
    • Days 4-6 – Primary Viremia, followed by viral replication
    • Day ~14 – Secondary Viremia
      • Viral Prodromal Symptoms develop before rash.
        • High Fever, Headache, Malaise, Loss of Appetite, Nausea
        • Prodromal symptoms are more mild in young children.
        • They are more significant adolescents/adults and those with immonodeficiencies, chronic steroid use, or chronic medical problems.
      • Rash ~10-21 days after infection
      • Maximally contagious 1-2 days before onset of rash.
      • Contagiousness decreases after rash scabs and resolves.
  • The Rash
    • Pruritic!
    • Maximally on the trunk!
      • Spread to arms, neck, and face, but less densely distributed.
      • Helps to distinguish from Smallpox!
    • Small macules evolve into vesicles.
      • Can involve the mucous membranes, especially the mouth.
      • “Dewdrops on Rose Petals.”
    •  Become pustules that eventually rupture and crust/scab (after ~12-72 hrs). 
      • Evolution is not uniform and the vesicles and scabs appear in different stages (also a distinguishing feature from Smallpox).
    • Heals without scarring, unless super infected, in 1-2 weeks.

Chicken Pox: Complications

  • Complications are rare in healthy young children, but more common in: [Freer, 2018]
    • Infants
    • Adolescents & Adults [Imam, 2017; Heitz, 2017;]
  • Complications: [Freer, 2018; Gnann, 2002]
    • Bacterial Superinfection of putules [Darmasseelane, 2018; Jain, 2015]
    • Pneumonia
    • Otitis Media
    • Neurological Problems
    • Hepatitis
    • Hemorrhagic Nephritis
    • Myocarditis [Kao, 2010]
  • Infection & pregnancy: [Freer, 2018]
    • During 1st & 2nd Trimester => Congenital VZV
      • Leads to skin scars, ocular defects, hypoplastic limbs, and neurologic abnormalities.
      • May lead to miscarriage.
    • After 5th/6th month of gestation, infection => asymptomatic chickenpox with subsequent early development of herpes zoster.
    • Maternal infection 5 days before or 2 days after delivery => severe newborn varicella with high mortality rate (~30%)

Chicken Pox: Treatment

  • Symptomatic management
    • Treat the itch!
    • Educate and try to prevent superinfection!
  • Antiviral Medications [Freer, 2018; Sauerbrei, 2016]
    • ex, acyclovir, valacyclovir, famcyclovir
    • Use for patients at risk for complications (ie, adolescents).
  • Immunotherapy [Freer, 2018]
    • Anti-VZV immunoglobulin 
    • Used for high risk patients including:
      • Immunocompromised
      • Newborns with maternal Varicella that develops 5 days before to 2 days after delivery
      • Premature, hospitalized infants

Moral of the Morsel

  • Vaccination is Very Good! Mortality and incidence of chicken pox has dropped dramatically since the widespread utilization of VZV vaccine in the US!
  • VZV is still around! Just because we don’t see it as often as we once did, doesn’t mean it won’t show up in your ED or office. Remain vigilant!
  • Most tolerate it well and recover without complication. Not everyone is so lucky, though. So if you are considering VZV infection, ask yourself whether the patient (or the patient’s close contacts) are at risk!


Freer G1, Pistello M2. Varicella-zoster virus infection: natural history, clinical manifestations, immunity and current and future vaccination strategies. New Microbiol. 2018 Apr;41(2):95-105. PMID: 29498740. [PubMed] [Read by QxMD]
Darmasseelane K1, Banks T1, Rjabova T1. Necrotising fasciitis as a complication of primary varicella infection in an immunocompetent child. BMJ Case Rep. 2018 Jun 21;2018. PMID: 29930190. [PubMed] [Read by QxMD]
Imam SF1, Lodhi OUH2, Fatima Z3, Nasim S4, Malik WT4, Saleem MS3. A Unique Case of Acute Cerebral Venous Sinus Thrombosis Secondary to Primary Varicella Zoster Virus Infection. Cureus. 2017 Sep 16;9(9):e1693. PMID: 29159001. [PubMed] [Read by QxMD]
Heitz AFN1, Hofstee HMA, Gelinck LBS, Puylaert JB. A rare case of Waterhouse- Friderichsen syndrome during primary Varicella zoster infection. Neth J Med. 2017 Oct;75(8):351-353. PMID: 29219830. [PubMed] [Read by QxMD]
Sauerbrei A1. Diagnosis, antiviral therapy, and prophylaxis of varicella-zoster virus infections. Eur J Clin Microbiol Infect Dis. 2016 May;35(5):723-34. PMID: 26873382. [PubMed] [Read by QxMD]
Jain J1, Thatte S1, Singhai P1. Periorbital varicella gangrenosa: A rare complication of chicken pox. Oman J Ophthalmol. 2015 Jan-Apr;8(1):64-6. PMID: 25709281. [PubMed] [Read by QxMD]
Kao KL1, Yeh SJ, Chen CC. Myopericarditis associated with varicella zoster virus infection. Pediatr Cardiol. 2010 Jul;31(5):703-6. PMID: 20087580. [PubMed] [Read by QxMD]
van der Maas NA1, Bondt PE, de Melker H, Kemmeren JM. Acute cerebellar ataxia in the Netherlands: a study on the association with vaccinations and varicella zoster infection. Vaccine. 2009 Mar 18;27(13):1970-3. PMID: 19186201. [PubMed] [Read by QxMD]
Gnann JW Jr1. Varicella-zoster virus: atypical presentations and unusual complications. J Infect Dis. 2002 Oct 15;186 Suppl 1:S91-8. PMID: 12353193. [PubMed] [Read by QxMD]
Sean M. Fox
Sean M. Fox

I enjoy taking care of patients and I finding it endlessly rewarding to help train others to do the same. I trained at the Combined Emergency Medicine and Pediatrics residency program at University of Maryland, where I had the tremendous fortune of learning from world renowned educators and clinicians. Now I have the unbelievable honor of working with an unbelievably gifted group of practitioners at Carolinas Medical Center. I strive every day to inspire my residents as much as they inspire me.

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  1. do you mean even if a pregnant and previously vaccinated patient with good Ab titers is exposed need the IG VZ?

    OR just the non up to date pregnant women

    • If the mother of a neonate gets primary Varicella (“Newborns with maternal Varicella that develops 5 days before to 2 days after delivery”), then she likely didn’t have “good titers,” although her actual titers I am not likely going to know in the ED.

      I’d be ultra-cautious in that case.

      Thank you,

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