Chickenpox is a disease caused by the varicella-zoster virus (VZV). It is characterized by a blistery rash.
What is going on in the body?
Chickenpox is characterized by an itchy rash that looks like very small blisters on a red base. The blisters look like dewdrops on top of a red pimple.
Chickenpox is usually acquired in childhood by inhaling the virus from an infected person. It is also acquired by touching the blisters of the chickenpox rash when there is still fluid in them.
The disease is usually more severe in adolescents and adults. It can be life-threatening in people with immune systems suppressed by disease or medication, pregnant women, and babies born to mothers who have chickenpox around the time of delivery.
A unborn baby can sometimes acquire VZV in the first 6 months of pregnancy. If this happens, the baby can be born with:
- scarring of the skin
- malformed arms or legs
- problems with the central nervous system
- eye problems
Once a person is infected with VZV, the virus remains in the body indefinitely. After recovery from chickenpox, the virus usually resides quietly in the sensory nerves, causing no symptoms for the rest of a person's lifetime.
Sometimes, however, especially in an older person or someone with cancer, the virus becomes active again, causing shingles, which is a painful infection along the nerves.
What are the causes and risks of the disease?
Chickenpox is a highly contagious disease caused by the varicella-zoster virus. VZV is a member of the herpes virus family.
What can be done to prevent the disease?
Chickenpox can usually be prevented with the varicella vaccine. The vaccine is routinely recommended for children, with the first dose at 12-15 months of age and the second at 4-6 years.
The vaccine is also strongly recommended for adolescents and adults who have never had chickenpox and were not vaccinated earlier.
People at high risk for severe chickenpox may be given varicella-zoster immune globulin.
How is the disease diagnosed?
Chickenpox is usually diagnosed based on the appearance of the rash. However, VZV can be detected and/or cultured from chickenpox blisters during the first few days of the rash. The person's blood can be tested to determine whether he or she has had chickenpox in the past.
Long Term Effects
What are the long-term effects of the disease?
The most common long-term effect is scarring of the skin. Normal chickenpox can leave temporary marks on the skin that take 6 to 12 months to fade. The most common complication of chickenpox is a bacterial infection of the skin such as cellulitis.
The virus can sometimes cause pneumonia, inflammation of the liver, and an infection of the central nervous system.
Chickenpox is a serious disease for adults, people with immune system suppression, and newborns whose mothers had chickenpox right around the time of delivery.
What are the risks to others?
If a person has chickenpox, it can be highly contagious to a person who has not had VZV. The contagious period begins about 2 days before the rash develops. The person is generally contagious as long as the blisters have fluid in them or until they crust over.
What are the treatments for the disease?
Acyclovir (i.e., Zovirax) is used to treat complicated or more severe cases of varicella. It is not routinely used to treat mild to moderate cases in healthy children. Other antiviral medications that can be used include famciclovir (i.e., Famvir), valacyclovir (i.e., Valtrex), vidarabine, and interferon.
Home care suggestions are designed to treat the symptoms. These include:
- acetaminophen (i.e., Tylenol) to treat discomfort and fever over 102 degrees. Aspirin should be avoided in a person with chickenpox because of a link between aspirin, chickenpox, and a serious neurological condition called Reye syndrome.
- cool, tepid baths. A cool or lukewarm bath with 1/2 cup of baking soda or oatmeal added to it will decrease itching from the rash. It may help to have several baths a day for the first few days of the rash.
- calamine lotion on the wet lesions (blisters that have ruptured) to reduce itching from the rash
- hydrocortisone cream on the dry lesions (blisters that have not ruptured) to reduce itching from the rash
- diphenhydamine (i.e., Benadryl), an antihistamine medication, for itching. The healthcare provider should be consulted before giving this medication to young children.
- a soft diet and cool fluids. Avoid salty or citrus foods.
- covering the hands of small children with gloves or socks to avoid scratching. Scratching can cause secondary infection of the scabs.
What are the side effects of the treatments?
Acyclovir can sometimes cause damage to the kidneys, or kidney toxicity.
What happens after treatment for the disease?
Most people recover without serious long-term effects. But the virus remains and may reactivate at any time to cause shingles.
How is the disease monitored?
Any new or worsening symptoms should be reported to the healthcare provider. No further monitoring is needed once a person recovers from VZV. If symptoms of shingles develop, a person should contact his or her healthcare provider.