WHAT IS IT?
VOL: 100, ISSUE: 15, PAGE NO: 27
WHAT IS IT?
- Chickenpox is a highly contagious illness caused by the varicella zoster virus (VZV).
- In most patients it is a mild, self-limiting illness, characterised by low-grade fever, malaise, and an itchy, vesicular rash.
- Transmission is by respiratory droplets or direct contact with vesicle fluid, and often occurs before the rash appears.
- After recovery from primary infection, VZV lies dormant in the nervous system and may result in shingles in later life.
- Chickenpox can be caught from contact with a person who has shingles but shingles cannot be caught from a person who has chickenpox.
- Systemic symptoms can precede the rash by up to six days and include fever, headache, backache, sore throat, and malaise.
- The rash begins on the trunk and spreads to the face and extremities.
- The characteristic lesions are vesicles with surrounding erythema, which develop into pustules then crust over. They are intensely itchy.
- Healing time is about 16 days.
- Over 90 per cent of people in the UK have had chickenpox by the age of 15 (International Herpes Management Forum, 1996).
- The annual incidence of chickenpox is estimated to be about six people per 1,000 (IHMF, 1996).
- Children between the ages of five and nine account for 50 per cent of all cases of chickenpox.
- Bacterial skin infection is the most common complication.
- Acute cerebellar ataxia may occur, particularly in older children.
- The disease is more severe in adults and complications, including varicella pneumonia, hepatitis and encephalitis, are more common.
- Deep round scars, commonly called pockmarks, are particularly likely in older children and adults.
- Mortality from chickenpox is reported to be about 1.4 per 100,000 in children and 31 per 100,000 in adults (Swingler and Volmink, 2001).
- Immunocompromised people have a 20-40 per cent risk of developing a severe progressive form of varicella, which can be fatal (IHMF, 1996).
- If maternal chickenpox occurs in the first half of pregnancy, there is a 1-2 per cent risk of foetal abnormality.
- Symptomatic treatment includes topical calamine lotion and/or sedating antihistamines to relieve itching and reduce sleeplessness, and simple analgesia to ease systemic symptoms and reduce fever.
- Patients are infectious from about 48 hours before to two days after the appearance of the rash.
- In immunocompromised people, antiviral treatment may reduce the severity of chickenpox and likelihood of clinical deterioration (Swingler and Volmink, 2001).
- Oral aciclovir is recommended for women who are more than 20 weeks pregnant and who present within 24 hours of the onset of the rash (Royal College of Obstetricians and Gynaecologists, 2001).
- Varicella zoster immunoglobulin is recommended for antibody-negative women who become exposed to chickenpox at any stage of pregnancy, providing it can be given within 10 days of contact (Public Health Laboratory Service, 2001).
Health Protection Agency: www.hpa.org.uk
International Herpes Management Forum: www.ihmf.org
NHS Direct: www.nhsdirect.nhs.uk