• Offer symptomatic treatment.
• Consider prescribing aciclovir for an immunocompetent 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 risk of complications, such as smokers or people using corticosteroids.
• Aciclovir is not recommended for otherwise healthy children with chickenpox.
• Give advice about contact with other people and when to seek medical advice.
• If serious complications (such as pneumonia, encephalitis, or dehydration) are suspected, admit to hospital.
• 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.
• This may be more common in people with eczema.
• Notify the relevant authorities if in Scotland or Northern Ireland (chickenpox is not a notifiable disease in England or Wales).
• For more information on managing a person who has been in contact with but not yet developed chickenpox, see the section Healthy person.

• These recommendations are pragmatic advice, based on recommendations from the Health Protection Agency [HPA, 2006; HPA and Association of Medical Microbiologists, 2010], the UK advisory group on chickenpox on behalf of the British Society for the Study of Infection [Ogilvie, 1998; Wilkins et al, 1998], the British National Formulary [BNF 54, 2007], and a review of the management of varicella-zoster infection [Allen, 2006].
• A Cochrane review on aciclovir for treating varicella in otherwise healthy children and adolescents [Klassen et al, 2005] did not find sufficient evidence to support the use of aciclovir in young, immunocompetent children with self-limiting, uncomplicated chickenpox. From the three studies identified, aciclovir was associated with a reduction in the maximum number of lesions and the number of days with fever, but there were no differences in the occurrence of complications of chickenpox in people taking aciclovir compared with placebo.
• Adults are more likely to develop complications of chickenpox than children. There is an indication that smokers and people with severe lung or cardiovascular disease, or those with a chronic skin disorder, are particularly at risk from complicated chickenpox [Wilkins et al, 1998; BNF 54, 2007].
• Recommendations vary between UK organizations regarding the use of aciclovir in immunocompetent adults with chickenpox [Ogilvie, 1998; Wilkins et al, 1998; HPA, 2006; BNF 54, 2007].
• A review by BMJ Clinical Evidence [Swingler, 2007] identified an RCT (n = 148) that found aciclovir given within 24 hours of rash onset reduced the number of lesions and time to full crusting of lesions compared with placebo (no significant difference in time to crusting of lesions if aciclovir was given 24–72 hours after rash onset). Two other RCTs identified did not find a significant difference in time to no new lesions with aciclovir given more than 24 hours after rash onset compared with placebo.
• CKS could find no recent trials looking specifically at the effect of aciclovir on preventing complications of chickenpox in an adult population.
• The recommendation to consider the possibility of bacterial superinfection is based on studies that have reviewed people admitted to hospital with chickenpox.
• In one UK study (n = 613), 32% of children and 17% of adults admitted to hospital with chickenpox had secondary bacterial skin infection [Bovill and Bannister, 1998]. Of the 25 children with secondary bacterial infection, three had toxin-mediated scarlet fever and one child had scalded skin syndrome. Five of the children with secondary bacterial infection had eczema. Bacteriaemia and toxic shock syndrome, although not seen in this study, may also occasionally occur.
• It is plausible that secondary bacterial superinfection is more common in people with eczema. Secondary bacterial infection is itself a common complication of eczema, and use of topical corticosteroids may exacerbate this. Clinical data are sparse, but a small case series supports this view: secondary bacterial infection was more common in children with eczema (31%; 10 of 32 children) than in healthy children (6%; 2 of 34 children) [Kubeyinje, 1995].
• The recommendation on reporting cases of chickenpox is from the Department of Health and the Health Protection Agency [DH, 2006; HPA, 2006].

• Urgently seek specialist advice regarding the need for diagnostic tests, counselling regarding the risk of fetal varicella syndrome, antiviral treatment, and follow up.
• Only prescribe an antiviral drug in primary care (with the informed consent of the woman) on the advice of a specialist.
• Offer symptomatic treatment.
• Give advice about contact with other people and when to seek medical advice.
• Monitor the woman closely (review daily, or earlier if her condition deteriorates).
• Refer for urgent hospital assessment if fever persists, or cropping of the rash continues after 6 days.
• Admit to hospital (preferably somewhere with access to specialists in obstetrics, infectious diseases, and paediatrics) if the woman has chest symptoms, neurological symptoms other than headache, haemorrhagic rash or bleeding, severe disease (e.g. dense rash with or without numerous mucosal lesions), or significant immunosuppression.
• Seek specialist advice from the local obstetric unit (even in the absence of complications) if monitoring will be difficult; the woman is in the latter half of pregnancy; or the woman has a complicated obstetric history, history of smoking, chronic lung disease, or poor social circumstances, or is taking steroids.
• Notify the relevant authorities if in Scotland or Northern Ireland (chickenpox is not a notifiable disease in England or Wales).
• For more information on managing a pregnant woman who has been in contact with but not yet developed chickenpox, see Pregnant woman.

• The recommendations for primary healthcare professionals on what to advise the woman, symptomatic treatment, and when to refer for specialist care are based on a guideline from the Royal College of Obstetricians and Gynaecologists (RCOG) on chickenpox in pregnancy [RCOG, 2007], guidance from the Health Protection Agency on the management of rash illness and exposure to rash illness in pregnancy [HPA, 2007a], and an article in the Drug and Therapeutics Bulletin [DTB, 2005a].
• The recommendation on reporting cases of chickenpox is from the Department of Health and the Health Protection Agency [DH, 2006; HPA, 2006].
• Basis for seeking urgent specialist advice:
• Pregnant women are more at risk of serious complications of varicella (e.g. fulminating varicella pneumonia). This risk is greatest in the second, and early in the third, trimester [DH, 2006].
• There are prescribing and drug licensing issues in pregnancy, and a potential need for intervention and follow up. The Royal College of Obstetricians and Gynaecologists' guideline on chickenpox in pregnancy [RCOG, 2007] advises that the pregnant woman needs to be informed of the small risk of fetal varicella syndrome and its implications, if she develops varicella or shows serological conversion in the first 28 weeks of pregnancy. The guideline recommends considering referral to a specialist centre for detailed ultrasonography at 16–20 weeks of gestation or 5 weeks after infection (if specialist advice has been sought, this is likely to be arranged by secondary care).
• Basis for antiviral treatment:
• Only limited data on the treatment of chickenpox in pregnancy are available [DTB, 2005a], and advice differs between organizations on which antiviral to use and at what stage of pregnancy, therefore CKS recommend seeking specialist advice.
• Guidance on the management of rash illness in pregnancy from the Health Protection Agency recommends offering a 7-day course of oral aciclovir or valaciclovir (with informed consent) if the woman presents within 24 hours of the onset of the rash (gestation not specified). The Health Protection Agency does not recommend antivirals after this time because evidence is lacking that they alter the natural history of the disease in an uncomplicated case [HPA, 2007a].
• The RCOG guidelines on chickenpox in pregnancy suggest a recommendation from the UK Advisory Group on Chickenpox to prescribe oral aciclovir (with informed consent) for pregnant women with chickenpox who are at more than 20 weeks of gestation and present within 24 hours of the onset of the rash. The RCOG state that aciclovir should be used cautiously before 20 weeks of gestation [RCOG, 2007].
• In one study of a group of immunocompetent adults, oral aciclovir taken within 24 hours of the rash onset reduced the duration of fever and symptoms of varicella infection when compared with placebo. The study was not sufficiently powered to detect any impact of early aciclovir on the serious complications of chickenpox [Wallace et al, 1992; RCOG, 2007].
• The RCOG guideline found data to suggest no increase in the risk of fetal malformation with aciclovir in pregnancy, although there is a theoretical risk of teratogenesis in the first trimester [RCOG, 2007].
• Varicella-zoster immunoglobulin has no benefit once chickenpox has developed [RCOG, 2007].

• Seek urgent specialist advice regarding further management.
• Give advice about contact with other people.
• Admit to hospital if serious complications (e.g. pneumonia, encephalitis) are suspected.
• Notify the relevant authorities if in Scotland or Northern Ireland (chickenpox is not a notifiable disease in England or Wales).
• For more information on managing neonates who have been in contact with but not yet developed chickenpox, see Neonate.

• CKS recommends seeking specialist advice on the management of neonates with chickenpox because of the increased risk of severe disease and complications in this group.
• The recommendation on reporting cases of chickenpox is from the Department of Health and the Health Protection Agency [DH, 2006; HPA, 2006].
• Neonates with chickenpox should be treated with aciclovir [HPA, 2007a; RCOG, 2007], but this should only be initiated by a specialist.
• The Royal College of Obstetricians and Gynaecologists guidelines on chickenpox in pregnancy state that varicella-zoster immunoglobulin is not beneficial if neonatal chickenpox has already developed [RCOG, 2007].
• The Health Protection Agency advises that if severe varicella develops in a neonate who has been given varicella-zoster immunoglobulin following exposure to chickenpox, treatment with high-dose intravenous aciclovir should be started as soon as possible [HPA, 2007a].

• Offer symptomatic treatment.
• Consider prescribing aciclovir for an immunocompetent adult with chickenpox who presents within 24 hours of rash onset, particularly for people with severe chickenpox or those at risk of complications.
• Seek urgent specialist advice regarding whether the mother should continue to breastfeed if she has chickenpox.
• Give advice about contact with other people and when to seek medical advice.
• Admit to hospital if serious complications (e.g. pneumonia, encephalitis) are suspected.
• Notify the relevant authorities if in Scotland or Northern Ireland (chickenpox is not a notifiable disease in England or Wales).

• CKS found no specific guidelines on the management of breastfeeding women with chickenpox. Therefore, CKS suggest symptomatic management as for healthy adults, in line with current knowledge about the use of analgesics/antipyretics and calamine in breastfeeding women.
• Adults are more likely to develop complications of chickenpox than children. There is an indication that smokers and people with severe lung or cardiovascular disease, or those with a chronic skin disorder, are particularly at risk from complicated chickenpox [Wilkins et al, 1998; BNF 54, 2007].
• Recommendations vary between UK organizations regarding the use of aciclovir in immunocompetent adults with chickenpox [Ogilvie, 1998; Wilkins et al, 1998; HPA, 2006; BNF 54, 2007].
• A review by BMJ Clinical Evidence [Swingler, 2007] identified an RCT (n = 148) that found aciclovir given within 24 hours of rash onset reduced the number of lesions and time to full crusting of lesions compared with placebo (no significant difference in time to crusting of lesions if aciclovir was given 24–72 hours after rash onset). Two other RCTs identified did not find a significant difference in time to no new lesions with aciclovir given more than 24 hours after rash onset compared with placebo.
• CKS could find no recent trials looking specifically at the effect of aciclovir on preventing complications of chickenpox in an adult population.
• CKS advise seeking specialist advice regarding whether a mother with chickenpox should breastfeed in view of the potential complications for the baby and differing recommendations between separate organizations:
• Recommendations on breastfeeding from the Health Protection Agency guidance on the management of rash illness and exposure to rash illness in pregnancy state that: if the mother has chickenpox, she should be allowed to breastfeed. If lesions are close to the nipple, milk should be expressed from the affected side until lesions have crusted. This milk can be fed to the baby if he or she is covered by varicella-zoster immunoglobulin and/or aciclovir. These treatments should be initiated by a specialist [HPA, 2007a].
• The American Academy of Family Physicians recommends: babies born to mothers who develop chickenpox within 5 days antepartum or within 2 days postpartum are at risk for more serious chickenpox infections. It is recommended that baby and mother be separated until the mother is no longer infectious, but expressed breast milk may be supplied, as long as the milk does not come into contact with active lesions [Lawrence and Lawrence, 1999].
• The recommendation on reporting cases of chickenpox is from the Department of Health and the Health Protection Agency [DH, 2006; HPA, 2006].

• Seek immediate specialist advice regarding confirming the diagnosis of chickenpox and whether urgent antiviral treatment is required.
• Offer symptomatic treatment.
• Give advice about contact with other people and when to seek medical advice.
• Admit to hospital if serious complications (e.g. pneumonia, encephalitis) are suspected.
• Notify the relevant authorities if in Scotland or Northern Ireland (chickenpox is not a notifiable disease in England or Wales).
• For advice on how to manage an immunocompromised person who has been exposed to but not yet developed chickenpox, see Immunocompromised person.

• Confirm that the person fulfils the criteria for immunosuppression (if in doubt, seek specialist advice).

• CKS recommends seeking specialist advice on the management of immunocompromised people with chickenpox because of the increased risk of severe disease and complications in this group.
• The recommendation on reporting cases of chickenpox is from the Department of Health and the Health Protection Agency [DH, 2006; HPA, 2006].
• People at higher risk of serious complications from chickenpox may be given antiviral drugs, such as aciclovir, to try to prevent severe illness [HPA, 2006].
• Even immunocompromised people who have received varicella-zoster immunoglobulin prophylaxis may develop severe or fatal varicella. These people should be carefully monitored and given aciclovir at the first sign of illness [DH, 2006].

• Offer paracetamol or ibuprofen to relieve pain or fever:
• The use of antipyretic agents should be considered in children with fever who appear distressed or unwell. Antipyretic agents should not routinely be used with the sole aim of reducing body temperature in children with fever who are otherwise well. The views and wishes of parents and carers should be taken into consideration.
• For further information, see Paracetamol/ibuprofen issues
• Consider the use of topical calamine lotion to alleviate itch.
• Chlorphenamine may be useful for itch associated with chickenpox for those who are 1 year of age or older.

• These recommendations are pragmatic advice. Treatment should be directed toward reducing symptoms, such as fever and itchiness [Allen, 2006; Heininger and Seward, 2006; HPA, 2006; NICE, 2007a; Papadopoulos, 2007].
• Calamine lotion:
• Calamine lotion is thought to relieve pruritus by evaporating from the skin to induce a cooling effect [Allen, 2006].
• In a literature review, no published evidence was found to support the use of calamine to alleviate pruritus in chickenpox. However, the authors felt that it has a good safety profile, and anecdotal reports suggest some degree of symptomatic relief [Tebruegge et al, 2006].
• CKS could not find any evidence to justify the use of topical crotamiton and colloidal oatmeal bath additives in chickenpox.
• Antihistamines:
• There is very limited evidence to support the use of topical or systemic antihistamines in relieving pruritus in those with chickenpox. Expert opinion is divided, but some experts find chlorphenamine useful from clinical experience. Piriton^®, but not generic chlorphenamine, is licensed for the symptomatic relief of itching due to chickenpox.
• Chlorphenamine should not be given to those less than 1 year of age as it is not licensed for use in this age group [ABPI Medicines Compendium, 2005a].
• In a literature review, only one randomized trial was found that investigated the effect of antihistamine in chickenpox [Tebruegge et al, 2006]:
• Dimetindene (a sedating antihistamine unavailable in UK) was found to be more effective than placebo in reducing itching severity scores, with some improvement in sleep disturbance and appetite [Englisch and Bauer, 1997].
• However, the study design was poor, as neither the method of randomization nor the blinding process was described [Tebruegge et al, 2006]. The differences in itching severity scores between the groups were small and of uncertain clinical value. The trial was undertaken by the manufacturer of dimetindene in Germany.
• CKS could not identify any other randomized trials on the effect of antihistamines (including chlorphenamine) in people with chickenpox.
• Evidence of harm:
• CKS found case reports of adverse effects associated with the use of topical diphenhydramine (with or without additional systemic diphenhydramine) in children with chickenpox [Woodward and Baldassano, 1988; Huston et al, 1990; Reilly and Weisse, 1990; Bernhardt, 1991; Chan and Wallander, 1991; McGann et al, 1992].
• Reported adverse effects included acute delirium, hallucinations, dilated pupils, urinary retention and facial grimacing. These were thought to be related to the antimuscarinic properties of the drug.
• CKS could not find evidence of adverse effects associated with other antihistamines in people with chickenpox.

• Offer paracetamol to relieve pain or fever.
• Ibuprofen may be considered but it should not be used beyond 27 weeks of gestation.
• For further information, see Choice in pregnancy or breastfeeding
• Consider the use of topical calamine lotion to alleviate itch.

• These recommendations are pragmatic advice. Treatment should be directed toward reducing symptoms, such as fever and itchiness [Allen, 2006; Heininger and Seward, 2006; HPA, 2006; Papadopoulos, 2007].
• Calamine lotion:
• Calamine lotion is thought to relieve pruritus by evaporating from the skin to induce a cooling effect [Allen, 2006].
• In a literature review, no published evidence was found to support the use of calamine to alleviate pruritus in chickenpox. However, the authors felt that it has a good safety profile, and anecdotal reports suggest some degree of symptomatic relief [Tebruegge et al, 2006].
• The safety of calamine lotion during pregnancy and lactation has not been established, but its use during these periods is not considered to constitute a hazard [ABPI Medicines Compendium, 2002].
• CKS could not find any evidence to justify the use of topical crotamiton and colloidal oatmeal bath additives in chickenpox.
• Antihistamines:
• Although chlorphenamine may be used during pregnancy for the treatment of allergic conditions [Schaefer et al, 2007], CKS found no evidence to support its use in pregnant women with chickenpox.
• No increased teratogenic risk has been reported in pregnancies exposed to chlorphenamine [Schaefer et al, 2007]. Although two cohort studies observed no increase in the frequency of congenital anomalies among more than 275 infants born to women who took chlorphenamine during the first trimester of pregnancy [NTIS, 2002], it is generally advised that drugs should be avoided if possible during the first trimester [BNF 54, 2007].
• The manufacturer of chlorphenamine warns there is inadequate evidence of safety in human pregnancy and use during the third trimester may result in reactions in neonates [ABPI Medicines Compendium, 2005a; ABPI Medicines Compendium, 2005b]. The manufacturer advises using the drug when the potential benefits outweigh the potential unknown risks to the fetus.

• Offer paracetamol or ibuprofen to relieve pain or fever.
• For further information, see Choice in pregnancy or breastfeeding
• Consider the use of topical calamine lotion to alleviate itch.

• These recommendations are pragmatic advice. Treatment should be directed toward reducing symptoms, such as fever and itchiness [Allen, 2006; Heininger and Seward, 2006; HPA, 2006; Papadopoulos, 2007].
• Calamine lotion:
• Calamine lotion is thought to relieve pruritus by evaporating from the skin to induce a cooling effect [Allen, 2006].
• In a literature review, no published evidence was found to support the use of calamine to alleviate pruritus in chickenpox. However, the authors felt that it has a good safety profile, and anecdotal reports suggest some degree of symptomatic relief [Tebruegge et al, 2006].
• The safety of calamine lotion during pregnancy and lactation has not been established, but its use during these periods is not considered to constitute a hazard [ABPI Medicines Compendium, 2002].
• CKS could not find any evidence to justify the use of topical crotamiton and colloidal oatmeal bath additives in chickenpox.
• Antihistamines:
• Although the sedating antihistamine chlorphenamine is licensed for relief of itching associated with chickenpox, there is very limited evidence to support the use of topical or systemic antihistamines in relieving pruritus in those with chickenpox.
• Chlorphenamine may inhibit lactation and may be secreted in breast milk [ABPI Medicines Compendium, 2005a; ABPI Medicines Compendium, 2005b].
• Given that there is no detailed knowledge about the effect of chlorphenamine on breastfeeding [Schaefer et al, 2007], CKS does not recommend its use in breastfeeding women.

• Offer paracetamol or ibuprofen to relieve pain or fever:
• The use of antipyretic agents should be considered in children with fever who appear distressed or unwell. Antipyretic agents should not routinely be used with the sole aim of reducing body temperature in children with fever who are otherwise well. The views and wishes of parents and carers should be taken into consideration.
• For further information, see Paracetamol/ibuprofen issues.
• Consider the use of topical calamine lotion to alleviate itch.
• Chlorphenamine may be useful for itch associated with chickenpox for children aged 1 year and above.

• These recommendations are pragmatic advice. Treatment should be directed toward reducing symptoms, such as fever and itchiness [Allen, 2006; Heininger and Seward, 2006; HPA, 2006; NICE, 2007a; Papadopoulos, 2007].
• Calamine lotion:
• Calamine lotion is thought to relieve pruritus by evaporating from the skin to induce a cooling effect [Allen, 2006].
• In a literature review, no published evidence was found to support the use of calamine to alleviate pruritus in chickenpox. However, the authors felt that it has a good safety profile, and anecdotal reports suggest some degree of symptomatic relief [Tebruegge et al, 2006].
• CKS could not find any evidence to justify the use of topical crotamiton and colloidal oatmeal bath additives in chickenpox.
• Antihistamines:
• There is very limited evidence to support the use of topical or systemic antihistamines in relieving pruritus in those with chickenpox. Expert opinion is divided, but some experts find chlorphenamine useful from clinical experience. Piriton^®, but not generic chlorphenamine, is licensed for the symptomatic relief of itching due to chickenpox.
• Chlorphenamine should not be given to those less than 1 year of age as it is not licensed for use in this age group [ABPI Medicines Compendium, 2005a].
• In a literature review, only one randomized trial was found that investigated the effect of antihistamine in chickenpox [Tebruegge et al, 2006]:
• Dimetindene (a sedating antihistamine unavailable in UK) was found to be more effective than placebo in reducing itching severity scores, with some improvement in sleep disturbance and appetite [Englisch and Bauer, 1997].
• However, the study design was poor, as neither the method of randomization nor the blinding process was described [Tebruegge et al, 2006]. The differences in itching severity scores between the groups were small and of uncertain clinical value. The trial was undertaken by the manufacturer of dimetindene in Germany.
• CKS could not identify any other randomized trials on the effect of antihistamines (including chlorphenamine) in people with chickenpox.
• Evidence of harm:
• CKS found case reports of adverse effects associated with the use of topical diphenhydramine (with or without additional systemic diphenhydramine) in children with chickenpox [Woodward and Baldassano, 1988; Huston et al, 1990; Reilly and Weisse, 1990; Bernhardt, 1991; Chan and Wallander, 1991; McGann et al, 1992].
• Reported adverse effects included acute delirium, hallucinations, dilated pupils, urinary retention and facial grimacing. These were thought to be related to the antimuscarinic properties of the drug.
• CKS could not find evidence of adverse effects associated with other antihistamines in people 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 1–2 days before the rash appears, but infectivity continues until all the lesions have crusted over (commonly about 5–6 days after the onset of illness):
• During this time, advise a person with chickenpox to avoid contact with:
• People who are immunocompromised (e.g. 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.
• Children with chickenpox should be kept away from school or nursery for 5 days from the onset of the rash.
• Air travel is not allowed until 6 days after the last spot has appeared.
• 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 — manifesting as sudden high grade pyrexia (often after initial improvement), erythema and tenderness surrounding the original chickenpox lesions.
• Dehydration — encourage and monitor fluid intake and seek medical attention if signs of dehydration develop (e.g. reduced urine output, lethargy, cold peripheries, reduced skin turgor).

• These recommendations are pragmatic advice and are based on those issued by the Health Protection Agency [HPA, 2006] the World Health Organization [WHO, 2007], an article on the management of chickenpox and shingles infection [Allen, 2006], and feedback from expert reviewers.

• 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 (e.g. pregnant women, immunocompromised people, neonates).
• For management of a person who has been exposed to shingles, see the CKS topics on Post-herpetic neuralgia and Shingles.

• Significant exposure takes into account [DH, 2006]:
• The type of varicella-zoster infection in the index case. The risk of acquiring infection from an immunocompetent person who does not have exposed zoster lesions is unlikely. Exposure is significant if the person has had contact with:
• Chickenpox.
• Disseminated zoster.
• Immunocompetent people with exposed lesions (e.g. ophthalmic zoster).
• Immunosuppressed people with localized zoster on any part of the body (because this group may have increased viral shedding).
• The timing of exposure in relation to the rash onset in the index case. Exposure is significant if the person was in contact with:
• Chickenpox — between 48 hours before onset of rash to crusting of lesions.
• Disseminated zoster — from 48 hours before onset of rash to crusting of lesions.
• Localized zoster — day of onset of rash until crusting of lesions.
• Closeness of contact. Exposure is significant if:
• Maternal/neonatal contact.
• Continuous home contact.
• Contact in the same room (e.g. house or classroom, or 2- to 4-bed hospital bay) for 15 minutes or more, or contact on large open wards (particularly paediatric wards).
• Face-to-face contact (e.g. having a conversation).
• People who are immunosuppressed include [DH, 2006]:
• Those being treated for malignant disease with immunosuppressive chemotherapy or generalized radiotherapy, or those who have received this within the past 6 months.
• Those who have received an organ transplant and are currently receiving immunosuppressive treatment.
• Those who have received a bone marrow transplant and are still considered to be immunosuppressed (including those within 12 months of finishing all immunosuppressive treatment, or longer for those who have developed graft-versus-host disease).
• Those receiving high-dose systemic steroids (until at least 3 months after treatment has stopped). For children, this includes those who have taken prednisolone, 2 mg/kg per day for at least 1 week or 1 mg/kg per day for 1 month (or equivalent doses). For adults, an equivalent dose is harder to define, but immunosuppression should be considered in those who have taken around 40 mg of prednisolone daily for more than 1 week.
• Those receiving immunosuppressive drugs alone (e.g. azathioprine, ciclosporin, methotrexate, cyclophosphamide, leflunomide, cytokine inhibitors), or in combination with lower doses of steroids, for at least 6 months after treatment.
• Those with primary immunodeficiency (e.g. severe combined immune deficiency syndromes, Wiskott–Aldrich syndrome).
• Those who are immunosuppressed because of HIV infection.
• Always seek specialist advice regarding the management of someone who is, or may be, immunocompromised.

• This recommendation is based on Department of Health guidance on immunisation against infectious disease: The 'Green Book' [DH, 2006].
• Post-exposure management aims to protect people at high risk of developing varicella and people who may transmit infection to those at high risk (e.g. healthcare workers) [DH, 2006].

• 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. People with a definite history of chickenpox or herpes zoster can be considered to be protected.
• If the person is not immune, advise them that they may develop chickenpox.
• Healthcare workers:
• Healthcare workers with significant exposure to the varicella-zoster virus who have been vaccinated or have a definite history of chickenpox or zoster can continue working (as they are considered protected), but should be advised to contact their occupational health department before patient contact if they feel unwell or develop a rash.
• Unvaccinated healthcare workers with a negative or uncertain history of chickenpox or herpes zoster should be serologically tested. Consider routine testing for healthcare workers born and raised overseas, for whom a history of chickenpox is a less reliable indicator of immunity.
• If there is no definite history of varicella-zoster virus infection but a varicella-zoster virus antibody test is positive, consider the person to be immune.
• Non-immune healthcare workers should be advised to avoid contact with high-risk patients for 8–21 days after their contact with chickenpox, and to report to their occupational health department before patient contact if they feel unwell or develop a fever or rash.
• If a healthcare worker has no varicella-zoster antibody, varicella vaccine should be offered to reduce the risk of exposing patients to varicella-zoster virus in the future.

• The definition of a healthcare worker includes people who work in hospitals and general practice who have contact with patients. Examples include [DH, 2006]:
• Medical and nursing staff.
• Ward cleaners.
• Catering staff.
• Ambulance staff.
• Receptionists in general practice.

• This recommendation is pragmatic advice, taking into account guidance from the Department of Health guidance on immunisation against infectious disease [DH, 2006] and guidelines on chickenpox in pregnancy from the Royal College of Obstetricians and Gynaecologists [RCOG, 2007].

• 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, 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 (weeks from the last menstrual period).
• Test for varicella-zoster immunoglobulin G (IgG) antibodies in primary care if test results can be available within 2 working days of first exposure. If this is not possible, urgently seek specialist advice because testing in secondary care and/or varicella-zoster immunoglobulin (VZIG) prophylaxis may be needed.
• If the test shows varicella-zoster immunoglobulin G, reassure the woman that she is immune and cannot catch chickenpox.
• If the woman's antibody status is negative, urgently seek specialist advice regarding the need for VZIG.
• Advise the woman to promptly seek advice from her doctor or midwife if she develops a rash and has had contact with chickenpox, regardless of whether she has received VZIG.

• Because chickenpox is a common childhood disease, more than 90% of pregnant women are immune. Therefore, although contact with chickenpox in pregnancy is common, primary infection is not (an estimated 3 in 1000 pregnancies are complicated by primary varicella-zoster infection) [RCOG, 2007].
• Women from tropical and subtropical areas are more likely to be seronegative for varicella-zoster immunoglobulin G and are therefore more likely to develop chickenpox [RCOG, 2007].

This recommendation is based on Department of Health guidance on the management of exposure to varicella [DH, 2006], guidance from the Health Protection Agency on the management of rash illness in pregnancy [HPA, 2007a], and guidance from the Royal College of Obstetricians and Gynaecologists on chickenpox in pregnancy [RCOG, 2007]:

• CKS suggests testing for varicella-zoster immunoglobulin G antibodies in primary care if the results can be available within 2 working days of first exposure (to allow time for referral to secondary care if necessary), taking into account the Royal College of Obstetricians and Gynaecologists guideline on Chickenpox in Pregnancy [RCOG, 2007], which states that if the woman's immune status is unknown, the administration of VZIG can be delayed until serology results are available, if the laboratory turnaround time is 24–48 hours. However, local arrangements may differ, and it is advisable to contact the local laboratory to determine whether a result will be available within this time.
• CKS recommends seeking specialist advice regarding the management of non-immune pregnant women who have been in contact with chickenpox, in view of the potential for the development of severe disease and serious complications for the woman and fetus and the possible need for varicella-zoster immunoglobulin.
• CKS found no published controlled trials of the use of prophylactic oral aciclovir in pregnancy. Aciclovir, valaciclovir, and famciclovir are not licensed in the UK for this indication and are generally not recommended [DTB, 2005a; HPA, 2007a].
• The local microbiologist or virologist will usually decide whether to give varicella-zoster immunoglobulin [DTB, 2005a].
• The Department of Health recommend that a pregnant woman who has a negative antibody status (or for whom results cannot be available within 10 days of exposure) should receive varicella-zoster immunoglobulin within 10 days of exposure [DH, 2006].

• Perform a general assessment to establish the neonate's risk of chickenpox, on the basis of the certainty of chickenpox in the contact and the level of exposure.
• If the neonate's mother is the contact, determine when, in relation to delivery, she developed chickenpox. If someone else is the contact, determine the age of the neonate at the time of contact.
• Seek urgent specialist advice regarding the need for testing and further management, and whether the mother should continue to breastfeed if she has chickenpox.
• All neonates with exposure from their mother, or elsewhere, must be followed up for 14–16 days by a GP, midwife, or health visitor, or in hospital. Monitor the infant for signs of infection for 14–16 days.

Recommendations regarding monitoring of an neonate who has been exposed to chickenpox are based on the Royal College of Obstetricians and Gynaecologists' guideline on Chickenpox in Pregnancy [RCOG, 2007], and a Drug and Therapeutics Bulletin [DTB, 2005a].

• CKS recommends seeking specialist advice in the management of a neonate who has been exposed to chickenpox or shingles because severe disease or complications can develop in this group. Depending on the time of exposure, there are a number of management strategies which may be undertaken in secondary care.
• Varicella-zoster immunoglobulin (VZIG) may not prevent chickenpox but is generally effective in reducing the severity of infection [Isaacs, 2000].
• The Health Protection Agency advises giving VZIG or intravenous aciclovir to the neonate depending on when the mother develops varicella in relation to delivery [HPA, 2007a]. This should only be done in a specialist setting.
• CKS advise seeking specialist advice regarding whether a mother with chickenpox should breastfeed in view of the potential complications for the baby and differing recommendations between organizations:
• Recommendations on breastfeeding from the Health Protection Agency guidance on the management of rash illness and exposure to rash illness in pregnancy state that: if the mother has chickenpox, she should be allowed to breastfeed. If lesions are close to the nipple, milk should be expressed from the affected side until lesions have crusted. This milk can be fed to the baby if he or she is covered by varicella-zoster immunoglobulin and/or aciclovir. These treatments should be initiated by a specialist [HPA, 2007a].
• The American Academy of Family Physicians recommends: babies born to mothers who develop chickenpox within 5 days antepartum or within 2 days postpartum are at risk for more serious chickenpox infections. It is recommended that baby and mother be separated until the mother is no longer infectious, but expressed breast milk may be supplied, as long as the milk does not come into contact with active lesions [Lawrence and Lawrence, 1999].

• 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 immunosuppression. If in doubt, seek specialist advice.
• Urgently seek specialist advice regarding further management.
• People who have had a significant exposure to chickenpox and who are immunocompromised should be tested for varicella-zoster antibody, regardless of their history of chickenpox. Test for varicella-zoster immunoglobulin G (IgG) antibodies in primary care if test results can be available within 2 working days of first exposure. If this is not possible, urgently seek specialist advice because testing in secondary care and/or varicella-zoster immunoglobulin prophylaxis may be needed.

This recommendation is based on Department of Health guidance on immunisation against infectious disease: The 'Green Book' [DH, 2006].

• CKS recommends urgently seeking specialist advice on the management of an immunocompromised person who has been in contact with chickenpox, in view of the potential for severe disease and complications in this group.
• The Department of Health recommends referral of anyone who fulfils the following criteria for consideration of varicella-zoster immunoglobulin prophylaxis [DH, 2006]:
• Significant exposure to chickenpox or herpes zoster, and
• A clinical condition that increases the risk of severe varicella (e.g. immunosuppressed people, neonates, and pregnant women), and
• No antibodies to varicella-zoster virus.
• CKS suggests testing for varicella-zoster immunoglobulin G antibodies in primary care if the results can be available within 2 working days of first exposure (to allow time for referral to secondary care if necessary), taking into account the practicalities of testing in a primary care setting and feedback from expert reviewers. However, local arrangements may differ, and it is advisable to contact the local laboratory to determine whether a result will be available within this time.
• The Department of Health recommends that an immunocompromised person who has a negative antibody status (or for whom results cannot be available within 7 days of exposure) should receive varicella-zoster immunoglobulin, ideally within 7 days of exposure [DH, 2006]. This should be done in a specialist setting.