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( Varicella , Chicken Pox )

The Facts

Chickenpox is a very common illness caused by the varicella-zoster virus. It is extremely contagious. The rash that it produces is usually harmless and goes away on its own.

While you can get chickenpox at any age, most cases occur before the age of 14. Anyone who's had the disease once is usually immune for life, although they can still get shingles, a painful skin rash caused when the varicella-zoster virus becomes active again, even many years after they've had chickenpox.

Chickenpox usually occurs in late winter and early spring. Since the introduction of the chickenpox vaccine, many children never get chickenpox.


The varicella-zoster virus may be spread through the air or by direct contact with the blisters (lesions) of someone infected with chickenpox or shingles.

Once someone is infected, the virus usually incubates for 14 to 16 days before a rash appears, although incubation can last from 10 days to 21 days. There are no symptoms during incubation and a person is contagious from 1 to 2 days before symptoms appear. The person remains contagious until all the blisters have dried and scabs have formed.

Symptoms and Complications

Flu-like symptoms start to develop a day or two before an itchy red rash appears. Fatigue, mild headache, fever, chills, and muscle or joint aches are typical. The rash emerges as raised red bumps that turn to teardrop-shaped blisters that are extremely itchy.

These blisters may appear anywhere on the body, usually starting on the face, trunk or torso, then spreading to the arms and legs. In some cases, the rash may even spread across your entire body, including areas such as the throat, mouth, and vagina.

The blisters come in waves, with new crops developing as old ones burst. New blisters stop forming within about 5 days. By the sixth day, most blisters will have burst, dried, and crusted over. Within 3 weeks of blisters appearing, most of the scabs will have disappeared.

Children usually have a much milder infection and recover faster than adults. Babies, adults, and those with weakened immune systems tend to have more severe and longer-lasting symptoms. They are at higher risk of developing complications, including inflammation of the brain (encephalitis) and pneumonia.

Newborns whose mothers develop chickenpox during early pregnancy are at risk for low birth weight and birth defects. If the mother develops chickenpox a week before birth, the newborn is at risk for a life-threatening infection.

Children who have had the chickenpox vaccine can still get chickenpox. However, they usually have a much milder case with a smaller number of blisters.

Cellulitis (a skin infection from bacteria) is by far the most common complication in children. It may leave scarring, especially if the child scratches the lesions. Necrotizing fasciitis ("flesh-eating disease") in children, though extremely rare, can occur as a complication of infection entering through the chickenpox lesions. Chickenpox blisters that appear in the mouth, throat, or anus are very uncomfortable. If the rash appears near the eyes, consult your doctor.

Like many viruses, the varicella-zoster virus is never completely gone once it has entered your body. Anyone who's had chickenpox carries dormant viruses in the roots of their nerve cells. These can sometimes reappear years later as shingles, a painful skin rash that affects a particular area of skin.

Shingles can appear at times of emotional stress, or when the immune system is low. It's not always known what has provoked the virus to come out of hiding. It's important to know that the shingles rash can transmit chickenpox. People who have already had chickenpox are immune, but people who haven't can get the virus from someone with shingles.

Making the Diagnosis

A doctor will know chickenpox by its symptoms and particularly by the rash. If needed, fluid from the blisters can be tested for the varicella-zoster virus for confirmation. All adults, newborns, people with weakened immune systems, or pregnant women with possible chickenpox should see their doctor.

Doctors will not want people with chickenpox sitting in their waiting room as it is very contagious and others in the room who have never had chickenpox and have not received the vaccination will be at high risk of catching it. If you or your children need medical attention, call ahead before visiting the doctor's office.

Treatment and Prevention

In most cases, treatment is directed at relieving symptoms until the illness goes away on its own. Non-medical therapy includes:

  • keeping the body cool, as heat and sweat aggravate itchiness
  • applying cool-water compresses to the affected skin areas to reduce itchiness
  • keeping nails cut short and hands clean, as bacteria found under fingernails can infect open skin lesions
  • taking daily baths with soap and water, which can prevent bacterial infections

Your doctor may advise a variety of medical treatments:

  • Over-the-counter medicated creams and ointments can be applied to the affected skin to reduce itchiness. These may contain local anesthetics. If the medication is being used for a child, be sure to read the package carefully to make sure that it is safe for children, and to find the appropriate dose. Talk to your pharmacist for advice on choosing the best medication.
  • Antihistamine liquids and pills can also ease severe itching.
  • Antiviral medications, such as acyclovir*, may help if taken early in the course of the illness. They are appropriate for high-risk people, including those with weakened immune systems, adults, and pregnant women but are seldom necessary for otherwise healthy children.
  • Acetaminophen may be used for fever. Anyone under the 18 years of age should not take acetylsalicylic acid (ASA) or ASA-containing products because these contain ingredients (salicylates) that may cause Reye's syndrome. This is a rare and often fatal inflammation of the brain and liver seen in children taking ASA, particularly during an episode of chickenpox or influenza.

If you've never had chickenpox, try to stay away from anyone who's infected until all the blisters have dried and scabs have formed. People at high risk who've been exposed to the chickenpox virus should see their doctor immediately as they may need immune globulin (antibodies against varicella zoster). This will provide temporary protection for about 3 weeks against the development of chickenpox or its complications. People most prone to the illness include those with low resistance to diseases, such as newborns, people who have AIDS, or people taking corticosteroids, transplant medications, or cancer medications.

A vaccine against chickenpox is available. In Canada, the chickenpox vaccine is part of the recommended immunization schedule. It's recommended that anyone over 12 months of age who has never had chickenpox should receive a single dose of the chickenpox vaccine. For older children, 2 doses should be given at least 3 months apart.  For people 13 years of age and over, the 2 doses are given 4 to 8 weeks apart. The chickenpox vaccine contains a live but weakened form of the varicella-zoster virus. The vaccine causes the immune system to make antibodies that defend you from future infection by the virus. It is 85% to 95% effective.

The vaccine sometimes causes a slight fever. In up to 6% of cases, a mild chickenpox-like rash may appear around the injection site. This is most likely to occur in people with weakened immune systems. Because this rash may be contagious, you should avoid contact with high-risk people such as pregnant women.

The vaccine isn't recommended for pregnant women, people with active untreated tuberculosis, those with blood disorders or a suppressed immune system, or those with severe allergic reactions to neomycin (an antibiotic) and gelatin.


*All medications have both common (generic) and brand names. The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For information on a given medication, check our Drug Information database. For more information on brand names, speak with your doctor or pharmacist.

All material copyright MediResource Inc. 1996 – 2017. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Source:

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