Chickenpox (chicken pox), also known as varicella, is a highly contagious infection caused by the varicella zoster virus. Although uncomfortable, most people recover within 1-2 weeks.
There is a blister-like rash, which first appears on the face and trunk, and then spreads throughout the body. Although not life-threatening, complications can arise.
Fast facts on chickenpox
Here are some key points about chickenpox. More detail is in the main article.
- Chickenpox is caused by the varicella zoster virus.
- Varicella has an incubation period of 10-21 days.
- Chickenpox is highly contagious.
- The infection spreads in a similar way to colds and flu.
- A diagnosis can normally be reached by observing the signs and symptoms.
The hallmark symptom of chickenpox is a rash.
Before the rash appears, there will be:
- a general feeling of being unwell (malaise)
- fever, which is usually worse in adults than children
- aching muscles
- loss of appetite
- in some cases, a feeling of nausea
After the rash appears, there will be:
- Rash: Severity varies from a few spots to a rash that covers the whole body.
- Spots: The spots develop in clusters and generally appear on the face, limbs, chest, and stomach. They tend to be small, red, and itchy.
- Blisters: Blisters can develop on the top of the spots. These can become very itchy.
- Clouding: Within about 48 hours, the blisters cloud over and start drying out. A crust develops.
- Healing: Within about 10 days, the crusts fall off on their own.
During the whole cycle, new waves of spots can appear – in such cases, the patient might have different clusters of spots at varying stages of itchiness, dryness, and crustiness.
A few people have more severe symptoms.
If the following occur, a doctor should be contacted:
- the skin around the spots or blisters becomes painful and red
- there are breathing difficulties
Most healthy individuals make a full recovery, as with a cold or flu, by resting and drinking plenty of fluids.
Chickenpox generally resolves within a week or two without treatment. There is no cure, but a vaccine can prevent it.
A doctor may prescribe medication or advise on how to reduce symptoms of itchiness and discomfort, and also on how to prevent the infection from spreading to other people.
Pain or fever: Tylenol (acetaminophen), which is available to purchase online, may help with symptoms of high temperature and pain. It is important to follow the instructions provided by the manufacturer. Aspirin containing products should NOT be used for chickenpox as this can lead to complications. Acetaminophen (Tylenol) can be used at any time during pregnancy.
Avoiding dehydration: It is important to drink plenty of fluids, preferably water, to prevent dehydration. Some doctors recommend sugar-free popsicles or Pedialyte for children who are not drinking enough.
Mouth soreness: Sugar-free popsicles help ease symptoms of soreness if there are spots in the mouth. Salty or spicy foods should be avoided. If chewing is painful, soup might be a good option, but it should not be too hot.
Itchiness: ltchiness can become severe, but it is important to minimize scratching to reduce the risk of scarring.
The following may help prevent scratching:
- keeping fingernails clean and as short as possible
- placing mittens or even socks over a child’s hands when they go to sleep, so that any attempt at scratching during the night does not cut the skin
- applying calamine lotion or having an oatmeal bath to reduce itching
- wearing loose clothing
Antiviral medication may be prescribed during pregnancy, for adults who get an early diagnosis, in newborns, and for those with a weakened immune system. Acyclovir is one example.
This works best if it is given within 24 hours of developing symptoms. Acyclovir reduces the severity of symptoms but does not cure the disease.
A vaccine is available for varicella. For children, 2 doses of the varicella vaccine are given, one at 12 to 15 months and one at age 4 to 6 years. These are 90 percent effective at preventing chickenpox.
In the United States, the chickenpox vaccine is routinely given to children.
Adults are more susceptible to complications than children, but even in adults, they are rare.
If the blisters become infected with bacteria, the risk of complications is greater.
Pregnant women, newborns, and infants up to 4 weeks old, as well as those with weakened immune systems, are more likely to experience complications.
If the skin around the spots and blisters becomes red and tender or sore, they may be infected. Some people with chickenpox can go on to develop pneumonia.
Encephalitis: An inflammation of the brain may occur.
Reye’s syndrome: This rare but serious condition can occur when children and teenagers are recovering from a viral infection, including chickenpox. It causes the liver and brain to swell.
Most people who develop complications will make a full recovery.
Chickenpox and pregnancy
Chickenpox can have added complications if it occurs during pregnancy.
During pregnancy, there is a slightly higher risk of developing pneumonia with chickenpox.
There is also a danger of passing the infection on to the fetus.
If infection occurs during the first 20 weeks of pregnancy, there is a higher risk of fetal varicella syndrome, which can lead to scarring, eye problems, brain drainage, and shortened arms or legs.
If the infection happens later in pregnancy, the varicella may be transmitted directly to the fetus and the baby can be born with varicella.
If you become exposed to varicella during pregnancy, whether chickenpox or shingles, it is important to talk to a doctor right away.
Chickenpox and a weakened immune system
The risks of catching chickenpox and developing complications are higher in a person with a weakened immune system.
- A weakened immune system can result if a person:
- is taking certain medications
- has cancer
- is undergoing treatment such as radio- or chemotherapy
- has a chronic condition, such as lupus or rheumatoid arthritis
Complications from chickenpox may include meningitis, sepsis or septicemia, or pneumonia.
What is shingles?
A person who has had chicken pox can develop shingles years later. Find out more.
Warning: The following images may be considered graphic:
Chickenpox on the back
Severe adult chickenpox
Herpes zoster flareup
Chickenpox develops in stages.
The itchy rash is one of the most common signs of chickenpox.
Chickenpox, colds, and flu spread in a similar way. People can be infected by touching the blisters directly or from breathing in particles of the virus from the blisters or from the air around someone who is infected.
Chickenpox is mostly transmitted by:
- direct contact with the blisters of someone who has the varicella zoster virus
- breathing in the virus particles from someone’s blisters
- breathing in small particles from the mouth of someone talking or coughing
Varicella has an incubation period of between 10 and 21 days. In other words, the rash will appear from 10 to 21 days after exposure to the virus.
An infected person is contagious about 2 days before the rash appears. The rash can involve 250 to 500 itchy blisters.
Chickenpox continues to be contagious for another 5 to 7 days, or until all of the blisters have become scabs.
When all the lesions have crusted over, those infected can no longer pass it on to others, but individuals with weakened immune systems may be contagious for longer.
In most cases, the pox marks heal without scarring.
Shingles can develop as a complication of chickenpox.
Chickenpox and shingles are caused by the same virus. Shingles occurs when the varicella zoster virus from a previous case of chicken pox becomes active again.
Complications of shingles can include:
- postherpetic neuralgia, with pain from shingles lasting long after the blisters have gone
- vision loss if shingles cause eye infections
- neurological problems due to inflammation in the brain
- skin infections, especially if blisters are not treated correctly
You cannot catch shingles from another person, but a person who has never had chickenpox or was never vaccinated can catch chickenpox from someone with shingles. However, you cannot get shingles from somebody with chickenpox.
Chickenpox is caused by a virus called varicella zoster. People become infected after being in contact with an infected child or adult.
Chickenpox is one of the most infectious diseases. People who have never had chickenpox and have never been vaccinated are at the highest risk of infection.
A doctor or nurse will know whether a child or adult has chickenpox just by looking and asking a few questions. No medical tests are required to aid in the diagnosis. On rare occasions, chickenpox may be confused with scabies or some types of insect bites.