Tuesday, February 01, 2005

I think I have chickenpox...

Chickenpox is a common disease caused by the varicella-zoster virus (VZV), which is part of the herpesvirus family. Although many people associate the word herpes with genital herpes, the herpesvirus family is made up of nearly 100 kinds of viruses, eight of which cause disease in humans. Examples of different herpesviruses are herpes simplex virus (which causes cold sores and genital herpes infections), Epstein-Barr virus (which causes infectious mononucleosis), and varicella-zoster virus (which causes chickenpox and shingles). 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.

Normally, chickenpox is a mild illness, but certain groups of people are more likely to have a more severe illness that could lead to complications. These include infants, adolescents, adults, and people with weak immune systems from either illnesses or from medications such as long-term steroid use. The most common complication of severe chickenpox illness in these groups of people is a bacterial infection that can involve many sites of the body including the skin around the blisters, bones, lungs, joints, and the blood. Other serious complications are due to the virus itself infecting the organs and include viral pneumonia, bleeding problems, and inflammation of the brain (encephalitis).

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).

If the mother had chickenpox in the past (before the pregnancy or any time more than a week before delivery), then the fetus receives antibodies through the placenta. That means the mom's immunity gets passed on to the baby through the placenta and breast milk, so it would be unlikely for the infant to get sick. But antibodies are not fail-safe; there is no 100% guarantee that a baby won't get the infection - it's just less likely. Or, the infant might have the disease, but it won't be as severe. It's also important for pregnant women to realize that they're at increased risk of chickenpox complications if they catch it for the first time while pregnant.

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.

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.

An antiviral medicine known as acyclovir may be prescribed for anyone over the age of 12, people with weakened immune systems (from diseases or medications), and those with long-term lung or skin diseases. The drug, which can make the chickenpox less severe, must be given within the first 24 hours after the rash appears. Acyclovir is not prescribed for children younger than 12 because the drug can have side effects. Your child's doctor can tell you if the medication is right for your child.


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