What Is Chickenpox?

Chickenpox is an infectious disease caused by the varicella virus. Most cases occur in children under age 15 but older children and adults can get it. It spreads very easily from one child to another.

Symptoms include an uncomfortable, itchy rash, fever and headache. The rash is like blisters and usually appears on the face, scalp or trunk. The disease is usually mild and lasts 5 to 10 days, but it sometimes causes serious problems. Adults and older children tend to get sicker from it. Do not give aspirin to anyone sick with chickenpox since the combination may cause Reye Syndrome.

How do people get chickenpox?

Chickenpox spreads from person to person by direct contact with fluid from broken chickenpox blisters or through the air by coughing or sneezing. Chickenpox is so contagious in its early stages that an exposed person who has not had chickenpox has a 70% to 80% chance of getting the disease.

After infection, the virus stays in the body for life. Although people can not get chickenpox twice, the same virus causes shingles. A person with shingles can spread the virus to an adult or child who has not had chickenpox, and that person can develop chickenpox.


Symptoms of chickenpox begin between 10 and 21 days after a person is exposed. The illness typically includes fever and a generally sick feeling. This is soon followed by itchy, red bumps that quickly become fluid-filled and are easily recognized as chickenpox. These skin blisters are round, about 5 millimeters to 10 millimeters across (about the size of a pencil eraser), with a red base. Sometimes, they are described as a "dew drop on a rose petal." They appear in various stages over the next few days and eventually crust over. These blisters may appear anywhere there is skin, even inside the mouth, throat or vagina. Some patients have only 50 blisters or fewer. Others have too many to count.

What is the treatment?

For some children, the rash may be no more than a passing inconvenience, but for others, it can be very unpleasant. Treatment is, therefore, aimed at controlling the symptoms.

Asking your child not to scratch their itch will probably fall on deaf ears, however, it is worth trying to distract them as best you can. Cut their fingernails very short and make sure that their hands and fingernails are kept clean.

If the rash or sores are very itchy, bathe the child in a warm (but not too hot) bath with half a cup of baking soda in it. Your pharmacist or doctor will also be able to recommend some anti-itch preparations if your child is very disturbed. Calamine lotion can be useful as well.


Chickenpox (varicella) vaccination is not included in the childhood immunization program in New Zealand as the Ministry of Health does not recommend the routine use of this vaccine for normal, healthy children. However, the vaccine is available and licensed for use in New Zealand, but it is not subsidized, so the patient or parent must pay for it. The vaccine can be given to children over about one year of age and adults. Children aged under 13 years require one dose, whereas anyone over 13 years requires a second booster shot about six weeks later.