Patients develop 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.
In this article, we will cover symptoms, diagnosis, treatment, and the chickenpox vaccine.
Here are some key points about chickenpox. More detail and supporting information 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 simply observing the signs and symptoms
What causes chickenpox?
The itchy rash is one of the most common signs of 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.
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
The condition is characterized by a rash; people who develop symptoms can get 250-500 itchy blisters.
In the majority of cases, the pox marks heal without scarring.
An infected person is contagious about 2 days before the rash appears, and then continues being so for another 5-7 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. Individuals with weakened immune systems may be contagious for longer.
Varicella has an incubation period of between 10 and 21 days - i.e. the rash will appear from 10-21 days after the patient has been exposed to the virus.
Chickenpox, colds, and flu spread in a similar way. People can be infected by touching the blisters directly; infection can also occur from breathing in particles of the virus from the blisters or from the air around someone who is infected.
Although you cannot catch shingles, 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.
Complications of shingles can include:
- postherpetic neuralgia - pain from shingles lasts long after the blisters have gone
- vision loss - from eye infections caused shingles in the area
- neurological problems - due to inflammation in the brain
- skin infections - more likely if blisters are not treated correctly
The following are common chickenpox symptoms:
Before the rash appears
- a general feeling of being unwell (malaise)
- fever (usually worse in adults than children)
- aching muscles
- loss of appetite
- sometimes there may be a feeling of nausea
After the rash appears
The above symptoms are then followed by:
- Rash - its severity varies considerably. Some patients may have just a few spots, while others are covered all over the body.
- Spots - the spots, which develop in clusters, generally appear on the face, limbs, chest, and stomach.
- Blisters - initially, there are small red spots that itch a lot. They then develop into spots with blisters on top - 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.
Other chickenpox symptoms
Most healthy individuals make a full recovery, as is the case with a cold or flu - just by resting and drinking plenty of fluids. A small percentage of patients have more severe symptoms.
If the following symptoms emerge, a doctor should be contacted:
- the skin around the spots and/or blisters becomes painful and red
- there are breathing difficulties
It is important for the patient to drink plenty of fluids to prevent dehydration and aid recovery.
Chickenpox generally resolves within a week or two without treatment - there is no medication or treatment to "cure" it.
A vaccine is available for varicella. For children, 2 doses of the varicella vaccine (one given at 12-15 months and one given at age 4-6) are 90 percent effective at preventing chickenpox.
A doctor may prescribe 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) may help with symptoms of high temperature and/or 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. Pregnant women can take acetaminophen (Tylenol) at any time during their pregnancy.
Avoiding dehydration - the patient should 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; make sure it is not too hot.
Itchiness - although itchiness can become severe and the urge to scratch may seem impossible to control, it is important to keep scratching down to a minimum to prevent future scarring of the skin.
The following may help if you have a child with chickenpox:
- keep fingernails as short as possible
- keep fingernails clean at all times
- place mittens or even socks over the child's hands when they go to sleep so that any attempt at scratching during the night does not cut the skin
- calamine lotions or oatmeal baths may help reduce symptoms of itching
- make sure the patient wears only loose clothing
Antiviral medication - may be prescribed to pregnant females, adults if a diagnosis is made early enough, newborns, and patients with weakened immune systems. An example of such a drug is Acyclovir.
This medication works best if it is given within 24 hours of developing symptoms. Acyclovir reduces the severity of symptoms but does not cure the disease.
Chickenpox vaccine - countries vary in their recommendations for the chickenpox vaccination. Vaccination usage is much more widespread in the United States than many parts of Europe. In the U.K., it is recommended for certain people, such as healthcare workers (not already immune), and those living with somebody whose immune system is weak.
In the U.S., 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 suffer complications.
If the skin around the spots and blisters becomes red and tender/sore, they may have become infected. Some people with chickenpox can go on to develop pneumonia.
Encephalitis - inflammation of the brain.
Reye's syndrome - this is a rare, but serious condition that can occur when children and teenagers are recovering from a viral infection, including chickenpox. It causes the liver and brain to swell.
Even though complications are possible, most patients who have them make a full recovery.
Chickenpox and pregnancy
The risk of developing pneumonia is higher if a pregnant lady has chickenpox.
A pregnant woman has a slightly higher risk of developing pneumonia if she has chickenpox. There is also a danger of passing the infection on to the unborn baby. Becoming infected during the first 20 weeks of pregnancy raises the risk of the fetus developing fetal varicella syndrome, which can lead to scarring, eye problems, brain drainage, and shortened arms and/or legs.
If the infection happens later in pregnancy, there is a risk that the varicella may be transmitted directly to the baby and the baby can be born with varicella. If you become exposed to varicella (chickenpox or shingles) while pregnant, talk to a doctor right away.
Chickenpox and weakened immune systems
People with weakened immune systems could be taking certain medications, may be suffering from cancer, or undergoing treatments, such as radio- or chemotherapy, or have a chronic condition, such as lupus or rheumatoid arthritis.
Complications from chickenpox may include meningitis, blood poisoning (septicemia), or pneumonia.
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.