Chickenpox

Overview

This Guidelines summary covers the primary care management of chickenpox in healthy children and adults, during pregnancy, in women who are breastfeeding, and in people who are immunocompromised.

This NICE Clinical Knowledge Summary (CKS) topic does not cover vaccination against chickenpox.

Reflecting on Your Learnings

Reflection is important for continuous learning and development, and a critical part of the revalidation process for UK healthcare professionals. Click here to access the Guidelines Reflection Record.

Transmission

• Chickenpox is infectious from 24 hours before the rash appears until the vesicles are dry or have crusted over, usually 5 days after the onset of the rash (this period may be longer in people who are immunocompromised).
• Once the infection has subsided, the virus persists in sensory nerve root ganglia. Years or decades later, it can reactivate and cause herpes zoster (shingles).
• It is possible to develop chickenpox after exposure to a person with shingles, but it is not thought possible to develop shingles from exposure to a person with chickenpox.

Complications in Children

• Chickenpox is usually a self-limiting disease in healthy children, however complications may occur, including: 
  • Secondary bacterial infection of the skin and soft tissues (for example impetigo, furuncles, cellulitis, erysipelas, necrotizing fasciitis) and scarring.
    • Secondary bacterial skin infections (most often caused by group A Streptococcus (GAS) and Staphylococcus aureus) may present with sudden high grade fever (often after initial improvement), erythema, and tenderness surrounding the original chickenpox lesions.
  • Neurological complications (for example Reye's syndrome, acute cerebellar ataxia, encephalitis, meningoencephalitis, polyradiculitis, myelitis).
  • In rare cases, myocarditis, glomerulonephritis, appendicitis, pancreatitis, Henoch–Schönlein purpura, orchitis, arthritis, vasculopathy, optic neuritis, iritis, and keratitis.

Diagnosis

• In most cases, the diagnosis can be made clinically from the characteristic chickenpox rash.
  • If there is doubt, a history of recent exposure to chickenpox (or shingles), or cases occurring in close contacts, may help confirm the diagnosis.
• Take a history asking about:  
  • Typical features of chickenpox, including:
    • A prodrome that includes nausea, myalgia, anorexia, and headache (particularly adolescents and adults).
    • General malaise, loss of appetite, and feeding problems.
    • Rash.
  • Recent exposure to chickenpox (or shingles).
  • Previous chickenpox infection or vaccination.
  • Risk factors for severe disease and complications such as:
    • Pregnancy.
    • Immunosuppression (including high dose corticosteroid use).
    • Chronic skin or respiratory disease.
  • Symptoms suggestive of complications such as shortness of breath, cough, chest pain, persistent or recurrent fever, reduced urine output, confusion or reduced level of consciousness.
• Examine the person: 
  • Look for fever and signs of severe illness.
  • Look for rash:
    • Small, erythematous macules appear on the scalp, face, trunk, and proximal limbs, which progress over 12–14 hours to papules, clear vesicles (which are intensely itchy), and pustules.
    • Vesicles can also occur on the palms and soles, and mucous membranes can also be affected, with painful and shallow oral or genital ulcers.
    • Vesicles appear in crops; stages of development of the rash can therefore differ on different areas of the body.
    • Crusting occurs usually within 5 days of the onset of the rash, and crusts fall off after 1–2 weeks.
    • Pictures of the typical chickenpox rash are available on the NHS website.
  • Look for signs of complications such as secondary bacterial infection of skin lesions, pneumonia, and encephalitis.
    • Prolonged or recurrent fever is suggestive of secondary infection.
  • Be aware that: 
    • Adults may experience a more widespread rash and more prolonged fever than children.
    • Immunosuppresed people with chickenpox may present with atypical rash and more extensive lesions (which may be haemorrhagic).
• Laboratory tests can be used for confirmation, but are rarely required in primary care.
  • Confirmation of infection may be required, for example, where there are implications for vulnerable contacts — discuss with a specialist if unsure.

For recommendations on differential diagnosis, refer to the full CKS topic.

Management in Adults and Children

From age 2 months onwards.

Management in Otherwise Healthy Children and Adults

• If serious complications (such as pneumonia, encephalitis, dehydration, or severe secondary bacterial infection of the skin) are suspected, admit to hospital.
• Consider prescribing oral aciclovir 800 mg 5 times a day for 7 days for an immunocompetent, non-pregnant adult or adolescent (aged 14 years or older) with chickenpox who presents within 24 hours of rash onset, particularly for people with severe chickenpox or those at increased risk of complications, such as smokers.
  • Aciclovir is not recommended for otherwise healthy children with uncomplicated chickenpox.
• Offer symptomatic treatment (see the section on Treatment for Adults and Children).
• Give advice about contact with other people and when to seek medical advice.
  • If the person develops a high temperature (particularly after initial improvement) with redness and pain surrounding the chickenpox lesions, consider bacterial superinfection and manage accordingly.

Advice for an Adult or Child with Chickenpox

• Advise the following simple measures to help alleviate symptoms:
  • Encourage adequate fluid intake to avoid dehydration.
  • Dress appropriately to avoid overheating or shivering.
  • Wear smooth, cotton fabrics.
  • Keep nails short to minimize damage from scratching and secondary bacterial infection from scratching.
• Advise that the most infectious period is 24 hours before the rash appears, but infectivity continues until all the lesions are dry and have crusted over (usually about 5 days after the onset of the rash).
  • During this time, advise a person with chickenpox to avoid contact with:
    • People who are immunocompromised (for example those receiving cancer treatment or high doses of oral steroids, or those with conditions that reduce immunity).
    • Pregnant women.
    • Infants aged 4 weeks or less.
  • Advise that children with chickenpox should be kept away from school or nursery until all the vesicles have crusted over.
• Inform the person to seek urgent medical advice if their condition deteriorates or they develop complications. Parents of young children with chickenpox should be particularly aware of:
  • Bacterial superinfection.
  • Dehydration.
• Offer written patient information on chickenpox, such as that available from the NHS.

Treatment for Adults and Children

• Consider offering: 
  • Paracetamol if pain or fever are causing distress (avoid non-steroidal anti-inflammatory drugs). Note that oral paracetamol is not licensed for use in children under 2 months of age.
  • Topical calamine lotion to alleviate itch.
  • Chlorphenamine for treating itch associated with chickenpox for people 1 year of age or older.

Management in Pregnant Women

From age 12 years to 60 years (Female).

• Admit to hospital (preferably somewhere with access to specialists in obstetrics, infectious diseases, and paediatrics) if a pregnant woman has suspected chickenpox and any of:
  • Respiratory symptoms.
  • Neurological symptoms.
  • Haemorrhagic rash or bleeding.
  • Severe disease (for example dense rash with or without numerous mucosal lesions).
  • Significant immunosuppression (including recent use of systemic corticosteroids).
• Consider/discuss the need for admission with a specialist if other risk factors for severe illness and complications are present such as:
  • Pregnancy approaching term.
  • Previous obstetric complications or risk factors.
  • Smoking.
  • Chronic lung disease.
  • Social risk factors.
  • Close monitoring in the community is not possible.
• For all other pregnant women with chickenpox, seek immediate specialist advice from an obstetrician regarding further management such as antiviral treatment and outpatient follow up for the fetus.
• Offer symptomatic treatment (see the section on Treatment for Pregnant Women with Chickenpox).
• Give advice about contact with other people and when to seek medical advice.

For more information on managing a pregnant woman who has been in contact with but not yet developed chickenpox, see the section on exposure to chickenpox, later.

For information on managing neonates with chickenpox, refer to the full CKS topic.

Advice for a Pregnant Woman With Chickenpox

• Advise the following simple measures to help alleviate symptoms:
  • Encourage adequate fluid intake to avoid dehydration.
  • Dress appropriately to avoid overheating or shivering.
  • Wear smooth, cotton fabrics.
  • Keep nails short to minimize damage from scratching.
• Advise that the most infectious period is from 24 hours before the rash appears, but infectivity continues until all the lesions have crusted over (commonly about 5 days after the onset of the rash):
  • During this time, advise a pregnant woman with chickenpox to avoid contact with:
    • People who are immunocompromised (for example those receiving cancer treatment or high doses of oral steroids, or those with conditions that reduce immunity).
    • Other pregnant women.
    • Infants aged 4 weeks or less.
• Inform the woman to seek urgent medical advice if her condition deteriorates or she develops complications, particularly respiratory symptoms.
• Offer written patient information, such as that from the Royal College of Obstetricians and Gynaecologists on Chickenpox and pregnancy.

Treatment for Pregnant Women with Chickenpox

• Consider offering: 
  • Paracetamol if pain or fever are causing distress (avoid non-steroidal anti-inflammatory drugs).
  • Topical calamine lotion to alleviate itch.
• Chlorphenamine is not recommended for the management of the itch of chickenpox in pregnancy.

Management in Breastfeeding Women

From age 12 years to 60 years (Female).

• Admit the woman to hospital if serious complications (for example pneumonia or encephalitis) are suspected.
• For all other breastfeeding women:
  • Consider prescribing aciclovir if the woman presents within 24 hours of rash onset, particularly if she has severe chickenpox or is at increased risk of complications.
  • Seek urgent specialist advice regarding whether she should continue to breastfeed and whether her baby requires treatment to minimise the risk of complications.
  • Offer symptomatic treatment (see the section on Treatment for Breastfeeding Women with Chickenpox).
  • Give advice about contact with other people and when to seek medical advice.
  • If a high temperature develops (particularly after initial improvement) with redness and pain surrounding the chickenpox lesions, consider bacterial superinfection and manage accordingly.

Treatment for Breastfeeding Women with Chickenpox

• Consider offering:
  • Paracetamol if pain or fever are causing distress (avoid non-steroidal anti-inflammatory drugs).
  • Topical calamine lotion to alleviate itch.
• Chlorphenamine is not recommended for the management of the itch of chickenpox in a breastfeeding woman.

Managing an Immunocompromised Person

• Admit the person to hospital if serious complications (for example pneumonia or encephalitis) are suspected.
• If complications are not suspected:
  • Seek immediate specialist advice to confirm the diagnosis of chickenpox and determine whether immediate admission is required to administer intravenous aciclovir. 
  • Offer symptomatic treatment. 
  • Give advice about contact with other people and when to seek medical advice.
  • If a high temperature develops (particularly after initial improvement) with redness and pain surrounding the chickenpox lesions, consider bacterial superinfection and manage accordingly. 

For advice for breastfeeding women with chickenpox, see the section on Advice for a Pregnant Woman With Chickenpox. For recommendations on management in neonates, refer to the full CKS topic.

Exposure to Chickenpox

From birth onwards.

Assessment of Chickenpox Contacts

• For all people with a history of exposure to chickenpox, establish whether:
  • The diagnosis of chickenpox in the contact is certain.
  • The exposure was significant enough to put the person at risk of infection.
  • The person has had chickenpox in the past.
  • The person is at increased risk of complications of chickenpox (for example pregnant women, immunocompromised people, and neonates).
  • The person is in contact with others at high risk of complications (for example healthcare workers).

For recommendations on significant exposure, refer to the full CKS topic.

Managing Children or Adults Who Have Been Exposed to Chickenpox

• Perform a general assessment to establish the person’s risk of chickenpox on the basis of their history of chickenpox, the certainty of chickenpox in the contact, and the level of exposure.
  • If the person’s exposure to chickenpox is not significant, or if they have a history of chickenpox, or if they are known to be immune to chickenpox, reassure.
  • If the person is not immune, advise them that they may develop chickenpox.
• For healthcare workers (including people who work in hospitals and general practice who have contact with patients) with a significant exposure to the varicella-zoster virus, advise that:
  • If they have a definite history of chickenpox or shingles and have had a significant exposure to the varicella-zoster virus, they can continue working as they are considered to be protected, however, if they develop a rash or fever, or feel unwell they should seek advice from occupational health before patient contact.
  • If they are not vaccinated and do not have a definite history of chickenpox or shingles, they should avoid contact with high-risk patients for 8–21 days from exposure and contact their occupational health department.

Managing Pregnant Women Who Have Been Exposed to Chickenpox

• Perform a general assessment to establish the woman’s risk of chickenpox, on the basis of her history of chickenpox, the certainty of chickenpox in the contact, and the level of exposure.
• If the woman has a definite history of chickenpox or shingles or two doses of a varicella containing vaccine, and is not immunocompromised, reassure her that she is not at risk of chickenpox because immunity can be assumed.
• If the woman has no history of chickenpox or shingles (or is uncertain) and has a history of significant contact, establish the stage of gestation and seek urgent specialist advice.
  • Testing for varicella-zoster immunoglobulin G (IgG) antibodies in primary care may be appropriate if results can be available within 24–48 hours of first exposure. Local arrangements may differ, so contact the local laboratory to determine whether a result will be available within this time — if this is not possible, testing in secondary care is needed.
• Advise all women to promptly seek advice if they develop a rash and/or symptoms and have had contact with chickenpox (regardless of whether they have received antivirals, VZIG or have a history of chickenpox, shingles, or varicella vaccine).

Managing Immunocompromised People Who Have Been Exposed to Chickenpox

• Perform a general assessment to establish the certainty of chickenpox in the contact, the level of exposure, and whether the person fulfils the criteria for immunocompromise.
• Seek same-day specialist advice regarding testing and management.

For recommendations on managing a neonate exposed to chickenpox, refer to the full CKS topic.

Prescribing Information

Chlorphenamine

Dose

• For children aged:
  • Less than 1 year—chlorphenamine is not recommended as it is not licensed in this group.
  • 1–2 years: give 1 mg twice daily.
  • 2–6 years: give 1 mg every 4–6 hours (maximum 6 mg daily).
  • 6–12 years: give 2 mg every 4–6 hours (maximum 12 mg daily).
  • 12–18 years: give 4 mg every 4–6 hours (maximum 24 mg daily).
• For adults: 
  • Give 4 mg every 4–6 hours (maximum 24 mg daily). If the person is elderly, reduce the dose to a maximum of 12 mg daily.
  • Avoid use in pregnancy and breastfeeding unless considered essential by a physician.

Aciclovir

Dose

• By mouth, for an adult or adolescent (aged 14 years or older):
  • 800 mg 5 times a day for 7 days.

For information on adverse effects, contraindications and cautions, and drug interactions associated with chlorphenamine and aciclovir, refer to the full CKS topic.