Chickenpox Dr Trisha Macnair Chickenpox is a common childhood illness that children catch at some point. Find out what symptoms to look for, when it's necessary to see a doctor and the most effective treatments.

In this article

What is it? Who's affected?

What are the symptoms? What's the treatment?

Chickenpox is a viral infection caused by the Herpes varicella zoster virus. It's spread in droplets inhaled into the respiratory tract. Complications are rare but serious, and can occur in previously healthy children.

Chickenpox tends to affect children under ten. Most children have had the infection by this age. In older children and adults, chickenpox can be more severe.

It's more common in late winter and spring. Children who are immunosuppressed (for example, on steroids) are particularly vulnerable to complications, as are newborn babies who may catch the infection from their mother in late pregnancy.

The incubation period (from exposure to onset of symptoms) is 14 to 24 days. The initial symptoms are mild fever and headaches. Younger children may seem generally grouchy.

These are followed within hours by the appearance of a typical rash. Crops of red spots appear, which quickly develop central fluid-filled blisters that are intensely itchy. After a couple of days these scab over and dry up.

The rash mostly affects the trunk, but may appear anywhere on the body, including the scalp and the mouth.

In about one in ten cases symptoms are so minimal the infection goes unnoticed.

Complications of the infection are uncommon but include viral pneumonia, secondary bacterial infection and encephalitis.

Talk to your doctor if you're unsure of the diagnosis or if your child seems particularly unwell, has a cough, headache, if the skin is particularly inflamed or infected, or there are other worrying symptoms.

For young babies or children with immunity problems, always seek medical advice.

Give pain-relieving syrup and plenty of fluids. Calamine lotion and antihistamine medicines may relieve the itching.

Keep your child's hands clean and their fingernails short. Try to discourage them from scratching the spots, as they can scar.

The spots may be infectious until they've fully scabbed over, but no child should need to be kept from school for more than five days.

In severe cases, antiviral treatment may be recommended.

Most children recover without long-term problems. But children at high risk who are exposed to chickenpox must be treated with immunoglobulin injections to prevent the infection, or antiviral drugs to treat it.

There is also a vaccine that can be given to prevent chickenpox.

After infection the virus lies dormant in the body but can emerge later to cause shingles.

This article was last medically reviewed by Dr Rob Hicks in December 2007