Chickenpox (varicella) is an infectious illness caused by a virus called varicella zoster. It is passed on by close contact with infected people and by breathing in droplets in the air from infected people. It is most common in children under the age of 10 in whom it is usually mild. The main sign of the illness is a rash with raised red spots on the face and head which may spread to other parts of the body. Chickenpox can be more serious in adults, in pregnant women and patients who have a poor immune system. Many people get chickenpox during childhood, but some get it only as teenagers or adults when it may be a much more severe infection, even in healthy people.

Chickenpox is very contagious. Symptoms include an itchy, blister-like rash in addition to other symptoms. Chickenpox illness usually lasts about 4 to 7 days. Children usually miss 5 to 6 days of school or childcare due to chickenpox.

For most people, getting chickenpox once provides immunity for life. A person can get chickenpox more than once, but it is uncommon.

Chickenpox is an illness caused by the varicella-zoster virus. It brings on an itchy rash with small, fluid-filled blisters. Chickenpox spreads very easily to people who haven't had the disease or haven't gotten the chickenpox vaccine. Chickenpox used to be a widespread problem, but today the vaccine protects children from it.

The chickenpox vaccine is a safe way to prevent this illness and the other health problems that can happen during it.

Symptoms

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The rash caused by chickenpox appears 10 to 21 days after you're exposed to the varicella-zoster virus. The rash often lasts about 5 to 10 days. Other symptoms that may appear 1 to 2 days before the rash include:

  • Fever.
  • Loss of appetite.
  • Headache.
  • Tiredness and a general feeling of being unwell.

Once the chickenpox rash appears, it goes through three phases:

  • Raised bumps called papules, which break out over a few days.
  • Small fluid-filled blisters called vesicles, which form in about one day and then break and leak.
  • Crusts and scabs, which cover the broken blisters and take a few more days to heal.

New bumps keep showing up for several days. So you may have bumps, blisters and scabs at the same time. You can spread the virus to other people for up to 48 hours before the rash appears. And the virus stays contagious until all broken blisters have crusted over.

The disease is by and large mild in healthy children. But sometimes, the rash can cover the whole body. Blisters may form in the throat and eyes. They also may form in tissue that lines the inside of the urethra, anus and vagina.


Signs and symptoms

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The classic symptom of chickenpox is a rash that turns into itchy, fluid-filled blisters that eventually turn into scabs. The rash may first show up on the chest, back, and face, before it spreads to the rest of the body. It usually takes about 1 week for all of the blisters to become scabs.

Some people who have been vaccinated against chickenpox can still get the disease. However, they usually have milder symptoms.

When to see a doctor

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If you think you or your child might have chickenpox, call your health care provider. Often, chickenpox can be diagnosed with an exam of the rash and other symptoms. You may need medicines that can help fight off the virus or treat other health problems that can happen because of chickenpox. To avoid infecting others in the waiting room, call ahead for an appointment. Mention that you think you or your child may have chickenpox.

Also, let your provider know if:

  • The rash spreads to one or both eyes.
  • The rash gets very warm or tender. This might be a sign that the skin is infected with bacteria.
  • You have more serious symptoms along with the rash. Watch for dizziness, new confusion, fast heartbeat, shortness of breath, shakiness, loss of the ability to use muscles together, a cough that becomes worse, vomiting, stiff neck or a fever higher than 102 F (38.9 C).
  • You live with people who've never had chickenpox and haven't gotten the chickenpox vaccine yet.
  • Someone in your household is pregnant.
  • You live with someone who has a disease or takes medicines that affect the immune system.


Chicken pox, which is caused by the varicella-zoster virus, is one of the most easily communicated diseases and is, therefore, highly contagious.

It is a common disease, being, for example, the second most frequently reported infectious disease in the USA. The potential number of individuals affected by varicella worldwide each year is 60 million, an increasing proportion of which are adolescents and young adults.

Although in most cases childhood varicella disease is not a life-threatening condition, it can cause major financial and social problems to parents in lost working time spent looking after their sick children, while the children themselves suffer from the disease and lose valuable time away from school.

Medical costs are also involved, such as hospital and doctor's charges and associated drug costs. Moreover, if an adolescent or adult becomes ill, the problems pertaining to lost working time and medical cost are even greater.

The disease

Varicella, commonly called chickenpox, is a viral disease caused by first exposure to the varicella-zoster virus. It presents itself as fever with a characteristic vesicular-papular rash and is highly contagious.

The virus then remains latent in the body and can later be reactivated and cause shingles (herpes zoster)

How does it spread?

The varicella virus especially attacks the mucous tissues of the upper respiratory tract. Airborne droplets generally from coughing or sneezing easily spread the virus from person to person.

It can also be spread directly, for example, by dirty handkerchiefs and by direct contact with the chicken pox lesions.

The likelihood that varicella will spread among children in schools or among family members is over 90 per cent. Isolating infected children by keeping them away from school will help but only vaccination will help reduce the spread of varicella.

The transmission is most likely within the first two days of the appearance of the rash. Varicella is contagious for up to five days but not after day six, and generally children can go back to school after this time.

The time from first contact with the virus until symptoms develop can range from nine to 21 days, but in most patients it is between 13 and 17 days.

Who can get it?

Many people contract varicella during childhood or adolescence but seronegative adults can contract varicella.

Complications

Although for many children chicken pox does not produce major health problems, complications can develop in some cases, especially pneumonia, which may be fatal.

Bacteria super infection of the skin is generally seen in immunocompetent children less than five years of age and can lead to unsightly scaring, particularly of the face, which may cause cosmetic concerns for life.

Varicella is more serious in adolescents and in adults than in children. The fever is higher and continues for much longer and the rash is much heavier.

The most important point is the much greater likelihood of complications: pneumonia, for example, can occur in up to 14 per cent of adult patients. Death also tends to be higher when varicella is contracted later in life.

The social and economic impact of chicken pox The full impact of childhood varicella on patients and on their families is often not appreciated.

Physically, varicella is very uncomfortable for patients because they have to endure discomfort from symptoms such as the characteristic pruritis, fever, chills, nausea and vomiting. Patients often need to be isolated while suffering from varicella and in many cases they suffer from permanent scaring as a result of bacteria super infection of the skin.

Moreover, the complication can be fatal. Varicella can cause financial problems because of lost earnings when parents stay at home to look after their kids or because older patients need to stay away from work.

Medical costs may also be high, especially if complications set in and the sufferer, whether child, adolescent or adult, needs to stay in hospital.

The vaccination option

As almost everyone will contract varicella at some point, the annual patient group size will equal the entire worldwide birth cohort. More importantly, where varicella is more prevalent among older age groups — in whom complications are more likely — it represents a major health threat.

It follows that some means of controlling the situation is vital, and vaccination is most effective.

It has been shown that routine vaccination programme for healthy children would prevent 94 per cent of all potential cases of chicken pox.

From a social perspective (including work-loss cost and medical cost) such a programme would save more than $5 for every dollar invested in vaccination

Vaccines such as varilrix from GlaxoSmithKline Biologicals

https://www.mayoclinic.org/diseases-conditions/chickenpox/symptoms-causes/syc-20351282