Chickenpox is an infectious viral disease caused by the varicella-zoster virus that produces flu-like symptoms and red itchy spots.  Usually, chickenpox is exposed to children, particularly under age 12. Before the vaccine was available, about 4 million children in the United States suffered from Chickenpox, numerous children were hospitalized, and about 100 children died every year because of chickenpox infections.  However, after the vaccine was designed by scientists, the number of patients who suffer from chickenpox has decreased dramatically. As people can see, chickenpox is most common in children, but it is possible that people will get it if they do not have the chickenpox vaccine. It is not considered a serious disease among people, but the infection is highly contagious. Therefore, an infected patient needs to be stay away from people until he or she recovers completely.
Chickenpox is caused by the varicella-zoster virus (VZV), a double-stranded DNA virus, which is included in the Alphaherpesvirinae subfamily.  Since the virus is infectious, people can get it easily from an infected person who has the symptoms of coughing and sneezing. Even touching the fluid from a chickenpox blister can give people the virus. Before the rash appears with the blister forming scabs, it usually takes two or three days for the virus to spread out through the body. Also, the varicella-zoster virus takes 10 to 20 days to incubate, break out, and cause symptoms in the patient. 
Each individual has different symptoms of chickenpox. The common symptoms of chickenpox are a red, itchy rash and small, blisters filled with fluid.  The rash first appears as small, red bumps, which look like insect bites. After the first symptom starts, it takes 1 or 2 days for the rash to appear on the body. Later on, the rash changes to the cloudy liquid-filled blisters. After that, the blister wall breaks and the rash becomes dry with brown scabs.  Chickenpox blisters are less than a quarter of an inch wide. Before the rash appears on the skin, it blisters, bursts, dries, and crusts over the body. Also, if the red spots disappear, a new rash will appear every day for about a week. If the patient has any other skin disorders such as eczema, which makes the skin itch and become sore, the rash may appear more extensively. 
Other symptoms of chickenpox are:
- Abdominal pain
- Sore throat
- Malaise (feeling of depression, unsatisfaction, and unhappiness) or irritability
- A dry cough 
Usually, the patient who suffers from chickenpox has the fever between 101º F to 105º F. However, when the blisters are disappeared, the temperature lowers and becomes normal. 
Even if chickenpox is mild disease, it is possible that chickenpox can bring numerous serious complications.
This is the list of people who may have serious complications when they have chickenpox.
- Infants whose mothers have not had chickenpox and not gotten the chickenpox (varicella) vaccine
- Teenagers especially under age 12
- Pregnant women
- People whose immune system has been damaged by other diseases
- People who take other medications for their chronic diseases
- People who suffer from other skin disorders 
There are several complications that people can get them from chickenpox.
- Skin infection
Although this complication is rare in healthy children, adults are easily exposed to the disease. Pneumonia is an infection of the lungs. Many various organisms such as bacteria and viruses can cause it. The severity of pneumonia depends on the types of organism that causes the disease. Pneumonia is very dangerous infection, because it can be deadly. 
- Chickenpox and shingles
It is possible that anyone who had chickenpox is likely to get an illness called shingles. Even though you recover from chickenpox infection completely, some of the varicella-zoster virus may stay in your nerve cells. Later on, the virus becomes active and reappears as shingles, a painful red spots that spreads in band of short-lived blisters. This virus is more exposed to adults who do not have strong immune systems than to children. Also, shingles can cause its own complication, postherpetic neuralgia. Even if the blisters are disappeared, you can still feel pain continuously from the shingles. 
- Chickenpox and pregnancy
Chickenpox is very severe and dangerous to pregnant women. If a pregnant woman has chickenpox, it can cause a lot of problems in a infant. Chickenpox can cause low birth weight of child and birth defects, limb abnormalities. If the mother gets chickenpox a few weeks before childbirth, the baby can have a serious, life-threatening infection. 
Most healthy children do not need any medical treatment. The doctor may prescribe an antihistamine to relieve rash and itching. However, the patient is exposed to the severe complications from chickenpox, doctors prescribe medications to curtail the duration of the infection and alleviate the severity of complications. 
The doctor may suggest an antiviral drug such as acyclovir (Zovirax) or another drug called immune globulin intravenous (IGIV). These medications helps to reduce the pain of the disease after the rash and blisters appear first time when they are given within 24 hours. Other antiviral drugs, such as valacyclovir (Valtrex) and famciclovir (Famvir), also relieve the severity of the disease. However these medications have been allowed to use for only adults, not for children. Also, the doctor may suggest to get the chickenpox vaccine, and this can decrease the severity of the virus. 
- Main Article: Vaccination
Chickenpox can be prevented with vaccinations, although it does not provice 100% protection from chickenpox. But people who have been vaccinated usually less severe symptoms and heal faster than those who have not been vaccinated. 
The chickenpox vaccine, Varivax, is recommended for:
- Young children
Children get vaccinated twice in their lives. They get the first vaccination between ages 12 and 15 months and the second one between ages 4 and 6 years.
- Unvaccinated older children
Children ages 7 to 12 years who haven't been vaccinated need to receive two vaccinations. The vaccinations should be given at least three months apart. Also, children age 13 or older who have not been vaccinated must be get vaccinations given at least four weeks apart.
- Unvaccinated adults
Adults who have not had chickenpox and people who work for children need to receive two vaccinations given four to eight weeks apart. However, a person that has had chickenpox, does not need to get vaccinated, because they are immune to the virus. There is possibility that one might get chickenpox more than once, but this is very unusual.
However, the vaccine isn't approved for:
- Pregnant women
- People with weakened immune systems (those who have HIV or on immune-suppressing medications)
- People who are allergies
Since chickenpox is not serious disease, it can be managed at home. Some treatments can be used at home to help a patient feel better and recover from it.
- Don't scratch.
Since scratching can cause scarring, you should not scratch. If you do so, the healing process will take a long time and the sores will become infected. Also, trim the fingernails so that they do not damage your skin when you scratch.
- Take to the tub.
Taking cool baths can help alleviate itching. Sprinkling the bath water with baking soda, uncooked oatmeal or colloidal oatmeal is also help to reduce the severity of chickenpox.
- Take a rest.
Taking a rest can help recover from the infection. Try to eat soft, bland food when you have chickenpox. If there are chickenpox sores developing in you mouth, avoid eating spicy, acidic or hard and crunchy food.
- Treat a fever.
Acetaminophen, Tylenol, or ibuprofen such as Advil or Motrin are not helpful to cure chickenpox. However, those medications can help lower a mild fever. Make sure you don't give aspirin to anyone with chickenpox. Aspirin can cause a serious condition called Reye's syndrome.   
- Avian influenza
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- Hepatitis C
- Human papillomavirus
- Infectious mononucleosis
- Swine influenza
- Yellow fever
- Chickenpox by several authors. Wikipedia, the free encyclopedia.
- Chickenpox MayoClinic.com.
- Chiceknpox (Varicella) WebMD.com.
- Infections-Chiceknpox KidsHealth.
- Chickenpox Mama's Health.
- Chickenpox netdoctor.
- Varicella Disease Questions & Answers Centers for Disease Control and Prevention.
- Chickenpox emedicinehelth.
- Complications of chickenpox during pregnancy WebMD.com.