Please note: this is for general information only - for a diagnosis of chicken pox, see your doctor.

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.  

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.

Signs and symptoms
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 children 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.  

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 child.  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 child 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.

Treatment
PLEASE NOTE: this information is general only - please see your doctor for specific recommendations.

Children 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. 

Consult a doctor immediately if the child 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.  

(Information taken from the Southern Cross website - www.southerncross.co.nz)