Varicella ( Chicken Pox ) Infection in Adults - Guideline for management

Publication: 01/08/2008  
Last review: 06/06/2018  
Next review: 06/06/2021  
Clinical Guideline
CURRENT 
ID: 1465 
Approved By: Improving Antimicrobial Prescribing Group 
Copyright© Leeds Teaching Hospitals NHS Trust 2018  

 

This Clinical Guideline is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Varicella (chicken pox) infection in adults - Guideline for management

Summary
Varicella ( Chicken Pox ) Infection in Adults

Investigations

    • Chickenpox is usually a clinical diagnosis.
    • In cases where there is doubt regarding the diagnosis, e.g. where the rash is atypical, then a swab of the lesions can be taken for viral PCR.

Management

  • Non-Antimicrobial management
    • Paracetamol is effective in relieving mild to moderate pain and pyrexia
    • Ibuprofen and other NSAIDs should be avoided
    • Chlorphenamine may relieve itch and reduce sleeplessness
  • Antiviral treatment
    Immunocompetent adults – uncomplicated disease
    • Adults who present within 24 hours of onset of rash, treat with oral Aciclovir electronic Medicines Compendium information on Aciclovir 800mg five times a day
    • Consider treating patients if they present within 24-48 hours of new vesicles appearing, especially if they are high risk for severe disease (e.g. smokers).

Immunocompetent adults – complicated disease

    • Adults who have evidence of complicated disease (including pneumonitis, encephalitis or hepatitis), treat with intravenous Aciclovir electronic Medicines Compendium information on Aciclovir 10mg/kg body weight 8hrly

Immunocompromised adults

    • Immunocompromised patients should be treated with intravenous Aciclovir electronic Medicines Compendium information on Aciclovir 10mg/kg body weight 8hrly.
    • Consider oral valaciclovir (1 gram three times a day) for mild disease if careful monitoring can be facilitated

Pregnant women

    • Pregnant women >20 weeks gestation with uncomplicated chickenpox who present within 24 hours of onset of rash, treat with oral Aciclovir electronic Medicines Compendium information on Aciclovir 800mg five times a day.
    • Pregnant women with severe or complicated chickenpox should be treated with intravenous Aciclovir electronic Medicines Compendium information on Aciclovir 10mg/kg 8hrly.
    • Aciclovir electronic Medicines Compendium information on Aciclovir treatment at <20 weeks gestation should be considered on a case by case basis

Duration of treatment

    • Immunocompetent and pregnant : 7 days
    • Immunocompromised : 10 days (some patients may need longer duration)

Infection prevention and control
Patients with primary Varicella zoster virus (chickenpox) should be placed in isolation.

Referral criteria

    • All immunocompromised patients and immunocompetent adults with complicated chickenpox should be referred to infectious diseases
    • Chickenpox during the first 20 weeks of pregnancy should be discussed with a virologist or infectious diseases specialist in conjunction with the obstetric team.

Back to top

Background

Chickenpox is caused by primary Varicella zoster virus (VZV) infection, a common, highly contagious human herpes virus. By the age of 18, over 90% of UK adults are seropositive for VZV, indicating prior infection1. After primary infection, the virus establishes latency in the dorsal root ganglion and can later reactivate to produce herpes zoster (HSV, shingles). There is a separate LTHT guideline relating to the management of herpes zoster.

Five to ten percent of adults in the UK are not immune to VZV, and this percentage increases in subtropical and tropical regions. Susceptible adults are of particular clinical significance because morbidity and mortality from chickenpox is greater in adults than in children.1

Back to top

Clinical Diagnosis

After an incubation period of 10-21 days, affected individuals develop fever, malaise and lethargy followed 24-48 hours later by a characteristic itchy rash. Vesicles occur in crops in a centripental distribution, largely affecting the trunk and face. The lesions initially begin as macules, developing into papules, vesicles then pustules, before crusting over. Presence of lesions at all stages of development suggests chickenpox over other differentials.

Chickenpox is highly infectious, with approximately 90% of non immune exposed individuals becoming affected1. Individuals are infectious 2 days prior to the rash developing until crusting of the lesions. VZV can be transmitted both through respiratory droplets and fluid from the vesicles.

Chickenpox is usually a relatively straightforward clinical diagnosis, however, disseminated herpes simplex, enterovirus or mycoplasma infections may produce similar rashes. Laboratory confirmation is not usually required other than for these atypical cases.

Back to top

Investigation

Chickenpox is usually a clinical diagnosis. In cases where there is doubt regarding the diagnosis, then a swab of vesicular fluid can be taken for HSV, VZV and enterovirus PCR:

  • Using the swab contained inside a Universal Transport Medium (UTM) pack, remove the top from a lesion and swab. This swab should then be placed in the pink liquid medium provided.
  • If a UTM pack is not available, then a standard wound swab can be used, but the tip should be cut off and placed in a dry white topped sterile universal container.

PCR is a sensitive and specific test for VZV. It is useful for old or crusted lesions but is expensive and takes at least 1 day to obtain a result. In cases where encephalitis or meningitis is suspected, PCR can also be performed on CSF.

Testing blood for the presence of VZV IgG antibodies is not helpful in diagnosing chickenpox and should not be performed. It is primarily used to determine immune status in important populations (e.g. healthcare workers).

Back to top

Treatment

Available antiviral agents

Aciclovir electronic Medicines Compendium information on Aciclovir is the principle treatment for VZV. It can be used orally (800mg 5 times daily) or intravenously (10mg/kg every 8 hours). It should be noted that higher doses of Aciclovir electronic Medicines Compendium information on Aciclovir are required to treat VZV compared to treating herpes simplex. Aciclovir electronic Medicines Compendium information on Aciclovir doses should be calculated according to ideal body weight and adjusted to renal function. Valaciclovir (the pro-drug of Aciclovir electronic Medicines Compendium information on Aciclovir ) 1 gram 3 times daily has much greater bioavailability and produces blood levels 3-4 times higher than oral Aciclovir electronic Medicines Compendium information on Aciclovir 1.

Uncomplicated Varicella in immunocompetent adults
Randomised controlled trials have shown that Aciclovir electronic Medicines Compendium information on Aciclovir reduces the number and time to healing of chickenpox lesions if started within 24hrs of onset of rash in immunocompetent adults4,5. These benefits were not seen if treatment was begun beyond 24hrs of onset 6,7.

  • Oral Aciclovir electronic Medicines Compendium information on Aciclovir 800mg 5 times daily for 7 days is recommended for all cases of chickenpox in adults if begun within 24hrs of onset of rash. (Evidence Level A)
  • Consideration should be given to treating patients if they present within 24-48 hours of new vesicles developing, especially if they are high risk (e.g. smokers)1.

Complicated Varicella in immunocompetent adults
Adults with respiratory or neurological symptoms, hepatitis, coagulopathy, extensive haemorrhagic rash or densely cropping vesicles should be referred for assessment by infectious diseases and treated with intravenous Aciclovir electronic Medicines Compendium information on Aciclovir therapy 10mg/kg every 8 hours1. (Evidence Level C)

Immunocompromised adults
Patients with disorders of cell mediated immunity are at high risk of severe VZV and should receive intravenous therapy initially. This includes those with primary immunodeficiency, advanced HIV with CD4 <200, solid organ transplants, bone marrow transplants within the last 12 months, chemo- or radiotherapy within the last 6 months, steroid use >40mg prednisolone/day for > 1 week within the last 3 months and those receiving immunomodulatory drugs1

  • Immunocompromised patients should usually be treated initially with intravenous Aciclovir electronic Medicines Compendium information on Aciclovir 10mg/kg every 8 hours. (Evidence Level A)
  • Subsequent treatment can be oral valaciclovir if there has been a good clinical response to intravenous therapy.
  • If mild disease is present (i.e. <50 lesions, normal LFTs and renal function) then consideration can be given to treating with oral valaciclovir on a case by case basis, provided close monitoring can be provided8.

Varicella in pregnancy
Primary chickenpox in pregnancy is uncommon, however, risks of complications from VZV increase greatly during pregnancy and are highest during the 3rd trimester. Complications include pneumonitis, hepatitis and encephalitis, with smoking a significant risk factor for VZV pneumonitis during pregnancy9. Overall, chickenpox is five times more likely to be fatal in pregnancy than in the non-pregnant adult1.

Aciclovir electronic Medicines Compendium information on Aciclovir is not known to be harmful in pregnancy10 although manufacturers advise use only when potential benefits outweigh risks11. It is not licensed for use in pregnancy in the UK, so the risks and benefits should be discussed with the patient beforehand12. (Evidence Level C)

  • Oral Aciclovir electronic Medicines Compendium information on Aciclovir 800mg five times daily for 7 days is recommended for pregnant women with chickenpox if they present within 24 hours of the rash onset and they are >20 weeks of gestation12. (Evidence Level C)
  • Aciclovir electronic Medicines Compendium information on Aciclovir treatment at <20 weeks gestation should be considered on a case by case basis12. (Evidence Level C)
  • Intravenous Aciclovir electronic Medicines Compendium information on Aciclovir 10mg/kg every 8 hours is recommended for all pregnant women with severe chickenpox12,13. (Evidence Level D)

If the pregnant woman develops chickenpox or shows serological conversion in the first 28 weeks of pregnancy, she has a small risk of fetal varicella syndrome (FVS) and she should be informed of the implications. Women who develop chickenpox in pregnancy should be referred to a fetal medicine specialist, at 16–20 weeks gestation or 5 weeks after infection, for discussion and detailed ultrasound examination.

Post-Exposure prophylaxis

Post exposure prophylaxis with Varicella zoster immunoglobulin (VZIG) may be given to attempt to avoid or attenuate severe chickenpox in high risk patients who have been exposed to an index case. VZIG can be considered in patients who fulfil the following criteria:

  1. They are at an increased risk of severe chickenpox (e.g. immunosuppressed patients, pregnant women) and
  2. Have had a significant exposure to chickenpox or shingles during the infectious period and
  3. Have no antibodies (immunity) to varicella zoster virus14

If a patient is thought to fulfil this criteria, the case should be discussed with the on call consultant virologist. VZIG has no role in the treatment of chickenpox once it has developed.

Vaccination

A live attenuated Varicella vaccine is available. At present, it is chiefly used to vaccinate non-immune individuals who are in regular close contact with patients at high risk of severe chickenpox. This may include non-immune healthcare workers or close family and friends of immunocompromised patients. The Varicella vaccine is contraindicated in immunosuppressed and pregnant patients due to its live attenuated formulation15

Back to top

Provenance

Record: 1465
Objective:

Aims

  • To improve the diagnosis and management of varicella zoster (chickenpox) infection in adults

Objectives

  • To provide evidence-based recommendations for appropriate investigation of varicella infection
  • To provide evidence-based recommendations for appropriate antimicrobial therapy of varicella infection
  • To recommend appropriate dose, route of administration and duration of antimicrobial agents.
  • To advise in the event of antimicrobial allergy.
  • To set out criteria for referral or specialist input.
Clinical condition: Varicella (chickenpox) infection
Target patient group: Adults
Target professional group(s): Secondary Care Doctors
Pharmacists
Adapted from:

Evidence base

References

  1. Tunbridge AJ, Breuer J, Jeffery KJ. Chickenpox in adults - clinical management. 2008, Journal of Infection: 57 (2):95-102.
  2. UKMi (2016) Do NSAIDs increase the risk of severe skin reactions in children with chickenpox? UK Medicine Information. www.ukmi.nhs.uk
  3. Gould, D. Varicella zoster virus: chickenpox and shingles. 2014, Nursing Standard. 28 (33), 52-58.
  4. AL-Nakib W, Al-Kandari S, El-Khalik DM, El-Shirbiny AM. A randomised controlled study of intravenous acyclovir (Zovirax) against placebo in adults with chickenpox. 1983, Journal of Infection; 6:49-56.
  5. Wallace MR, Bowler WA, Murray NB, Brodine SK, Oldfield EC. Treatment of adult varicella with oral acyclovir: A randomized, placebo-controlled trial. 1992, Annals of Internal Medicine; 117:358-63.
  6. Andreoni M, Canfarini M, Grint PC, Martorelli M, Di Luzio Paparatti U, Rocchi G. A double blind, placebo controlled trial of efficacy and safety of oral acyclovir (Zovirax) in the treatment of chickenpox in adults. 1992, European review for medical and pharmacological sciences: 14:63-9.
  7. Klassen TP, Hartling L, Wiebe N, Belseck EM. Acyclovir for treating varicella in otherwise healthy children and adolescents. 2005, Cochrane Database of Systemic Reviews; (4):CD002980.
  8. Albrecht MA. Treatment of Varicella (chickenpox) infection. March 30 2017, UpToDate Topic 8336 Version 19.0
  9. Harger JH, Ernest JM, Thurnau GR et al. Risk factors and outcome of varicella-zoster virus pneumonia in pregnant women. 2002, Journal of Infectious Diseases; 185: 422-7.
  10. Stone KM, Reiff-Eldridge R, White AD, et al. Pregnancy outcomes following systemic prenatal acyclovir exposure: Conclusion from the international acyclovir pregnancy registry, 1984-1999. 2004, Birth defects research. Part A, Clinical & molecular teratology; 70:201-7.
  11. British National Formulary – 8 February 2018
  12. Royal College of Obstetricians and Gynaecologists. Green-top Guideline No.13: Chickenpox in pregnancy. January 2015.
  13. Gnann, J. Current antiviral treatments for Varicella. 2006, Herpes; 13(S1):13A-15A.
  14. Public Health England: Guidance for issuing Varicella-zoster immunoglobulin (VZIG) – August 2017
  15. The Green Book: chapter 34 (Varicella) – August 2015

Evidence levels:
A. Meta-analyses, randomised controlled trials/systematic reviews of RCTs
B. Robust experimental or observational studies
C. Expert consensus.
D. Leeds consensus. (where no national guidance exists or there is wide disagreement with a level C recommendation or where national guidance documents contradict each other)

Approved By

Improving Antimicrobial Prescribing Group

Document history

LHP version 1.0

Related information

Not supplied

Equity and Diversity

The Leeds Teaching Hospitals NHS Trust is committed to ensuring that the way that we provide services and the way we recruit and treat staff reflects individual needs, promotes equality and does not discriminate unfairly against any particular individual or group.