Chicken Pox (Symptoms, treatment)
In New Zealand approximately 50,000 cases of chicken pox occur each year. Approximately 90% of New Zealand children will contract chicken pox at some stage. Symptoms include fatigue, mild fever and loss of appetite, followed by a red rash. The peak incidence of the disease is in early spring.
Chicken pox is a highly infectious and very common childhood disease. It is caused by the varicella zoster virus, a member of the herpes family of viruses. It is usually a mild, self-limiting disease in healthy children but it can be severe if contracted by babies, immune-suppressed children or adults.
One bout of chicken pox gives lifelong immunity from contracting the disease again. However, the virus remains in the body for life and can be reactivated as shingles (herpes zoster). Shingles can occur at any age but is most common in adults over 60 years of age.
In New Zealand approximately 50,000 cases of chicken pox occur each year. The majority of these cases occur in children and approximately 90% of New Zealand children will contract chicken pox at some stage. The peak incidence of the disease is in early spring.
Initial symptoms of chicken pox include fatigue, a mild fever, lack of appetite and a feeling of being generally unwell. This is quickly followed (within 24 hours) by the development of a red rash. The rash usually appears on the chest and/or back first, later spreading to the face, scalp, arms and legs.
Twelve to 48 hours later the rash develops into small red spots. These then turn into yellow blisters, which burst and dry up 3 - 4 days after they appear. There may be several crops of spots occurring over 4 - 5 days. The spots cause itching, which may be severe. They may occur all over the body including the mouth and genital area. Some people may have only a few spots whereas others will have hundreds.
Full recovery from chicken pox usually takes 7 - 10 days after the symptoms first appear.
Bacterial infection of the skin is the most common complication of chicken pox. Rare complications of chicken pox include pneumonia and encephalitis (swelling of the brain).
Transmission and Incubation Period
The virus is spread in droplets of saliva through the air or by direct contact with the fluid from the blisters of the infected person. Coughing and sneezing are the most common modes of transmission, particularly in children.
Once infection with the virus had occurred, the incubation period (the time until symptoms appear) is between 10 and 21 days. The person is infectious from 2 days before the rash first appears until after the final crop of blisters have formed scabs, approximately 7 – 10 days later. The nature of the infectious period makes it very difficult to prevent the disease from spreading.
People with chicken pox should remain at home until they are no longer infectious. Supportive treatment includes:
- Rest
- Pain relief such as paracetamol to relieve fever. Aspirin should not be given, as this has been associated with Reye’s disease (a rare disorder affecting the liver and brain) in children with chicken pox.
- Itching can be treated with lotions such as calamine available from a pharmacy.
- Tepid baths with ½ cup of sodium bicarbonate or solutions such as Pinetarsol added can also be helpful in relieving itching.
- Because the mouth and throat can be affected, offer soft food and cool drinks. Avoid salty foods and citrus fruits.
- To prevent infection of the sores, trim children’s fingernails short and wash hands frequently with antibacterial soap. Discourage scratching as much as possible.
- Dress children in light, loose fitting clothing or pyjamas. Overheating and friction from clothing can worsen itching.
- Antiviral medications such as Zovirax may be prescribed for some people.
For a diagnosis of chicken pox see a doctor or practice nurse. Consult a doctor immediately if the person seems very sick, confused or difficult to waken, or if they have trouble walking or have a stiff neck. Also consult a doctor if the blisters become infected or if there are spots in the eyes, ears or mouth.
Chicken pox and Pregnancy
Chicken pox can cause foetal abnormalities if a non immune woman contracts the disease between the 8th and 20th week of pregnancy. Additionally, there is a risk of serious disease in the newborn baby if the mother contracts chicken pox between the 5th day before delivery and the 2nd day after the baby is born.
Children with chicken pox should therefore be kept away from pregnant women and newborn babies until they are no longer infectious. Pregnant women who have not had chicken pox should see their doctor for control measures if they are exposed to the disease.
Immune-compromised people - for example those who are HIV positive, organ transplant recipients and children with leukaemia - are also susceptible to serious illness as a result of the chicken pox virus.
Although a vaccine is available against chicken pox, it is not part of the Ministry of Health National Immunisation Schedule for healthy children in New Zealand. However, the vaccine is available at a cost through your GP.
For information on chicken pox vaccination, please see your GP or practice nurse, or contact:
For more information about chicken pox, contact:
Your GP or practice nurse
Plunketline, 0800 933 922
Healthline, 0800 611 116
Baker, H (1999). Chicken pox. Gale Encyclopaedia of Medicine, Edition 1, p669. InfotracHealthReferenceCenter – Academic
KidsHealth (2006) Chicken pox. The Paediatric Society of New Zealand and Starship Foundation 2005-2006. Auckland.http://www.kidshealth.org.nz/index.php/ps_pagename
/contentpage/pi_id/194
Ministry of Health (2006) Varicella (chicken pox and shingles). Immunisation Handbook 2006. Wellington. Ministry of Health.
Last Reviewed - 13/12/06
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