Chickenpox is a common disease caused by the varicella-zoster virus (VZV), which is part of the herpesvirus family. Varicella-zoster virus spreads in the air through coughs or sneezes or through contact with fluid from inside the chickenpox blisters.

Chickenpox, which occurs most often in the late winter and early spring, is very contagious - if exposed to an infected family member, about 80% to 90% of those in a household who haven't had chickenpox will get it. However, immunization of children with the chickenpox vaccine that's now available is expected to decrease cases of the disease dramatically over the next few years.

Although it's more common in kids under the age of 15, anyone can get chickenpox. A person usually has only one episode of chickenpox in his or her lifetime. But the virus that causes chickenpox can lie dormant within the body and can cause a different type of skin eruption later in life called shingles, also referred to as herpes-zoster.

Signs and Symptoms
Chickenpox is a viral infection that causes a red, itchy rash on the skin. The chickenpox rash usually appears first on the abdomen or back and face, and then spreads to almost everywhere else on the body, including the scalp, mouth, nose, ears, and genitals.

The rash begins as multiple small, red bumps that look like pimples or insect bites. They develop into thin-walled blisters filled with clear fluid, which then becomes cloudy. The blister wall breaks, leaving open sores, which finally crust over to become dry, brown scabs. One of the most characteristic features of the chickenpox rash is that all stages of the lesions can be present at the same time.

Chickenpox blisters are about a quarter to half an inch wide, have a reddish base, and appear in bouts over 2 to 4 days. Some children have only a few blisters, whereas others have several hundred. The rash may be more extensive or severe in kids who have skin disorders such as eczema.

Some children have a fever, abdominal pain, or a vague sick feeling a day or 2 before the rash appears. These symptoms may last for a few days, and fever stays in the range of 100 to 102 degrees Fahrenheit (37.7 to 38.8 degrees Celsius), although it may occasionally be higher. Younger children often have milder symptoms and fewer blisters than older children or adults.

Anyone who has had chickenpox as a child is at risk for a complication later in life called shingles. After an infection, some of the varicella-zoster virus may remain inactive in nerve cells near the spinal cord. Many years later, the virus can reactivate and resurface as shingles. When it reactivates, it affects the nerve to the skin. Symptoms, such as a tingling feeling, itching, or pain followed by a rash with red bumps and blisters appear only in the area of the skin that the nerve goes to.

Contagiousness
The contagious period for chickenpox begins about 2 days before the rash appears and lasts until all the blisters are crusted over. A child with chickenpox should be kept out of school until all of the blisters have dried, which is usually about 1 week, but you don't have to wait until all the scabs fall off to let your child get back to a normal schedule.

Pregnant women, as well as people with diseases or problems with their immune system, should not be near a person with chickenpox. If a pregnant woman who hasn't had chickenpox in the past contracts it (especially before 20 weeks), the fetus is at risk for birth defects. If she develops chickenpox 5 days before to 2 days after delivery, the newborn is at risk for life-threatening varicella (the mother has transferred the virus to the baby, but she hasn't had time to produce and transfer antibodies, which fight off infection, to the baby before it's born).

People who haven't had chickenpox can also catch it from someone with shingles, but they cannot catch shingles itself. Why can't a person catch shingles from someone else? It's because shingles can only develop from a reactivation of the varicella-zoster virus in a person who has previously had chickenpox.

Prevention
Since 1995, a varicella vaccine has been given to children older than 12 months, as well as adults. The vaccine is about 70% to 85% effective at preventing mild infection, and more than 95% effective in preventing moderate or severe disease. People who do develop chickenpox after vaccination have much milder symptoms with fewer skin blisters and a fast recovery.

Incubation
The incubation period for chickenpox is 10 to 21 days after exposure; most cases appear in 14 to 17 days. For example, if one child in a family breaks out with chickenpox picked up at school, siblings probably will show symptoms about 2 weeks later.

Duration
Chickenpox usually lasts 7 to 10 days in children, but typically lasts longer in adults.

Professional Treatment
A virus causes chickenpox, so your child's doctor won't prescribe antibiotics (which are for bacterial infections). However, your child may require antibiotics if the sores become infected by bacteria, a common complication.

Home Treatment
Most home treatment is aimed at relieving the annoying itch of chickenpox and the accompanying fever and discomfort. However, NEVER use aspirin to reduce pain or fever in children with chickenpox or certain other viral illnesses. Using aspirin in such cases has been associated with a serious disease, called Reye syndrome, which can lead to liver failure and even death.

Some measures you can take to help your child get through this itchy, uncomfortable time:

• Use wet compresses or give baths in cool or lukewarm water every 3 to 4 hours for the first few days. Oatmeal baths, available at the supermarket or pharmacy, can help to relieve itching. (Baths do not spread chickenpox.)
• Pat (don't rub) the body dry.
• Put calamine lotion on itchy areas (but don't use it on the face, especially near the eyes).
• Give your child foods that are cold, soft, and bland because chickenpox in the mouth may make drinking or eating difficult. Try to avoid feeding your child anything that's highly acidic or especially salty, like orange juice or pretzels.
• Ask your child's doctor or pharmacist about pain-relieving creams you can apply to sores in the genital area.
• Give your child acetaminophen (such as Tylenol) regularly to help relieve pain from mouth blisters.

And although it's tempting, children should be discouraged from scratching. Tell your child to come to you for help when faced with the urge to scratch. In addition, trim your child's fingernails and keep them clean to help lessen the effects of scratching, including broken blisters and infection.

When to Call Your Child's Doctor
Most chickenpox infections require no special medical treatment. Call your child's doctor immediately if your child:

• has fever that lasts for more than 4 days or rises above 102 degrees Fahrenheit (38.8 degrees Celsius)
• has a severe cough or trouble breathing
• has an area of rash that leaks pus (thick, discolored fluid) or becomes red, warm, swollen, or sore
• has a severe headache
• is unusually drowsy or has trouble waking up
• has trouble looking at bright lights
• has difficulty walking
• seems confused
• seems very ill or is vomiting
• has a stiff neck

Call your child's doctor if you're uncertain about whether your child's problem is chickenpox, if you have a question, or if you're concerned about a possible complication. The doctor can guide you in watching for complications and in helping you choose medication to relieve your child's itching.

Source: kidshealth.org