Chickenpox, also known as varicella is a viral infection caused by the varicella-zoster virus (VZV) which brings about itchy rashes with small, fluid-filled blisters.
Chickenpox is a disease that is highly contagious to people who haven't had the disease or been vaccinated against it. It causes a blister-like rash, itching, tiredness, and fever. The rash appears first on the stomach, back and face and can spread over the entire body causing between 250 and 500 itchy blisters. Chickenpox can be serious, especially in babies, adults, and people with weakened immune systems. The best way to prevent chickenpox is to get the chickenpox vaccine.
Anyone who hasn’t had chickenpox or gotten the chickenpox vaccine can get the disease. Chickenpox illness usually lasts about five to seven days. Children usually miss five to six days of school or childcare due to chickenpox.
Chickenpox is a very contagious disease spread by closeness and contact with someone with chickenpox. The causal organism, varicella-zoster virus also causes shingles. Chickenpox is easily passed between members of families and school classmates through airborne particles, droplets in exhaled air, and fluid from the blisters or sores. The virus spreads easily from people with chickenpox to others who have never had the disease or been vaccinated. The virus spreads mainly by touching or breathing in the virus particles that come from chickenpox blisters, and possibly through tiny droplets from infected people that get into the air after they breathe or talk, for example. It also can be transmitted indirectly by contact with articles of clothing and other items exposed to fresh fluid from open sores.
Chickenpox can be spread from people with shingles to others who have never had chickenpox or received the chickenpox vaccine. In these cases, a person might develop chickenpox, not shingles. Varicella virus remains dormant after the acute chickenpox syndrome. It may sometimes be recurrent as a limited area of blisters that look like chickenpox; this syndrome is called shingles or herpes zoster. Shingles is much less contagious than chickenpox. It is not transmitted by airborne virus but rather by contact with blisters.
For most people, getting chickenpox once provides immunity for life. However, for a few people, they can get chickenpox more than once, although this is not common.
What is the Contagious Period for Chickenpox?
A person with chickenpox can spread the disease from one to two days (often times up to 5 days) before and five days after the rash appears. When all of the sores have crusted over and are dry, the person is considered no longer contagious.
It takes about two weeks (from 10 to 21 days) after exposure to a person with chickenpox or shingles for someone to develop chickenpox.
What does chickenpox look like?
The rash of chickenpox develops in groups with raised red spots arriving first, progressing to blisters filled with clear fluid, like a drop of water on the skin. The blisters may be dimpled in the centre. They may break, and reform, then finally form sores before drying up as scabs or crusts. They have been described best as grouped blisters on a red base in different stages at the same time; some areas may just be forming blisters, while another area may already be crusting over. The crusts will come off on their own.
Doctors generally diagnose chickenpox based on the telltale rash.
If there's any doubt about the diagnosis, chickenpox can be confirmed with laboratory tests, including blood tests or a culture of lesion samples.
Chickenpox infection appears 10 to 21 days after exposure to the virus and usually lasts about five to 10 days. The rash is the telltale indication of chickenpox. Other signs and symptoms, which may appear one to two days before the rash, include:
Loss of appetite
Tiredness and a general feeling of being unwell (malaise)
Once the chickenpox rash appears, it goes through three phases:
Raised pink or red bumps (papules), which break out over several days
Small fluid-filled blisters (vesicles), forming from the raised bumps over about one day before breaking and leaking
Crusts and scabs, which cover the broken blisters and take several more days to heal
The best way to prevent chickenpox is to get the chickenpox vaccine. Children, adolescents, and adults should get two doses of chickenpox vaccine. Two doses of the vaccine are at the least 90% effective at preventing chickenpox. When you get vaccinated, you protect yourself and others in your community.
Chickenpox vaccine is very safe and effective at preventing the disease. Most people who get the vaccine will not get chickenpox. If a vaccinated person does get chickenpox, it is usually mild with fewer red spots or blisters and mild or no fever.
Before routine chickenpox vaccination, virtually all people had been infected by the time they reached adulthood, sometimes with serious complications. Today, the number of cases and hospitalizations is down dramatically.
The chickenpox vaccine isn't approved for:
People with weakened immunity, such as those with HIV or people taking immune-suppressing medications
People who are allergic to gelatin or the antibiotic neomycin
Talk to your doctor if you're unsure about your need for the vaccine. If you're planning on becoming pregnant, consult with your doctor to make sure you're up to date on your vaccinations before conceiving a child.
Treatment Options for Chickenpox
In otherwise healthy children, chickenpox typically requires no medical treatment. Your doctor may prescribe an antihistamine to relieve itching. But for the most part, the disease is allowed to run its course.
Most of the treatments for chickenpox are aimed at decreasing the symptoms, such as severe itching. A non-aspirin analgesic like acetaminophen (Tylenol) can be used to decrease the fevers and aches. Children should never be given acetylsalicylic acid (aspirin) or aspirin-containing cold medications because of the risks for developing Reye's syndrome (a severe brain disease associated with liver and brain dysfunction and death).
In addition, soothing lotions and moisturizers such as calamine lotion or any other similar over-the-counter preparation can be applied to the rash. Diphenhydramine (Benadryl) or other antihistamines can be helpful in controlling the itching. Always discuss these treatment options with your health-care practitioner.
In addition to medications, there are also preventive measures that are needed. For young children, it is important to keep nails trimmed in order to minimize injury due to scratching and to control the risks for secondary bacterial infections like impetigo or Staphylococcus (staph infection).
Lastly, in severe cases or people at high risk for severe disease, acyclovir (Zovirax) can be prescribed. Acyclovir is an antiviral drug that has been used to shorten the duration of the infection. This medication has only been shown to be effective if started within one to two days of onset of the chickenpox rash. Most commonly, this treatment is reserved for patients with other diagnoses that put them at risk for severe disease (adults, pregnant women, severe skin diseases, immunodeficiency).
Dealing With Discomfort
To help relieve the itchiness, fever, and discomfort of chickenpox:
Use cool wet compresses or give baths in cool or lukewarm water every 3 to 4 hours for the first few days. Oatmeal bath products, available at supermarkets and drugstores, can help to relieve itching. (Baths do not spread the rash.)
Pat (don't rub) the body dry.
Put calamine lotion on itchy areas (but don't use it on the face, especially near the eyes).
Serve foods that are cold, soft, and bland because chickenpox in the mouth can make drinking or eating difficult. Avoid feeding your child anything highly acidic or especially salty, like orange juice or pretzels.
Ask your doctor or pharmacist about pain-relieving creams to apply to sores in the genital area.
Give your child acetaminophen regularly to help relieve pain if your child has mouth blisters.
Ask the doctor about using over-the-counter medicine for itching.
Trim your child's fingernails or cover their hands with socks or mittens to keep them from scratching, which could lead to infection as well as to possible scarring.
Leave your baby's nappy off as much as possible to allow the vesicles to dry out and scab.
Dissolve 1/2 teaspoon of salt in a glass of warm water and use as a gargle to ease mouth sores. In older children, use lozenges or sprays containing a mild anaesthetic.
Give age-appropriate paracetamol for fever and chickenpox symptoms. Paracetamol is more appropriate rather than ibuprofen or other non-steroidal anti-inflammatory drugs because these drugs may cause adverse skin reactions during chickenpox infection. Never give aspirin to children under 16.
Avoiding dehydration. Drink plenty of fluids, preferably water, to prevent dehydration. Some doctors recommend sugar-free popsicles or Pedialyte for children who are not drinking enough.
Make sure to wear only loose clothing.
Possible Complications of Chickenpox
Complications can and do occur from chickenpox. Infection of the open pox sore by bacteria can injure the skin, sometimes causing scarring, especially if the patient scratches the inflamed area. Bacterial skin infection with group A Streptococcus ("strep" or "impetigo") is, in fact, the most common complication of chickenpox in children. Other complications are much less common. In children, the central nervous system may be affected. A disorder of the cerebellar portion of the brain ("cerebellitis" or "cerebellar ataxia") may occur with wobbliness, dizziness, tremor, and altered speech. Encephalitis (inflammation of the brain with headaches, seizures, and decreased consciousness) may occur as well as damaged nerves (nerve palsies). Reye's syndrome, a potentially fatal combination of liver and brain disease, may occur in children that take aspirin or salicylate products. (Children with fever should not take aspirin.) Other complications include bloodstream infection (sepsis or "blood poisoning" from skin infection) and dehydration.
Pneumonia is the more common complication in teens through adults. Death from varicella may occur even in healthy children.
People with certain conditions are at risk of severe complications and death:
Human immunodeficiency virus (HIV or AIDS)
Lupus and other connective tissue or autoimmune diseases
Leukemia and other cancers
People taking immune-suppressing drugs, such as cortisone-related medications, tumor necrosis factor inhibitors, and chemotherapy
People who have had transplants
Infants, teens, and adults
A pregnant woman who has never had chickenpox or the vaccine should avoid touching or being in the same room as a person with suspected chickenpox. Not only is she at risk for pneumonia caused by the chickenpox virus, the foetus is at risk for infection in the womb (congenital varicella syndrome) up until 20 weeks gestation. Congenital varicella causes multiple birth defects, such as skin scarring and malformed limbs. It is fortunately very rare. Newborn infants whose mothers develop chickenpox five days before or two days after birth are at highest risk of severe chickenpox. These babies may develop symptoms within two weeks of birth. This is because there is not enough time for the mother to develop varicella antibody to pass on to the baby. The fatality rate for these babies is up to 30%. If the baby develops symptoms at 10-28 days of age, it is likely to be mild.
When to Call the Health Care Provider
Some people are more likely to have a serious case of chickenpox. Call a health care provider if
the person at risk of serious complications:
is less than 1 year-old
is older than 12 years of age
has a weakened immune system
is pregnant, or
develops any of the following symptoms:
fever that lasts longer than 4 days
fever that rises above 102°F (38.9°C)
any areas of the rash or any part of the body becomes very red, warm, or tender, or begins leaking pus (thick, discoloured fluid), since these symptoms may indicate a bacterial infection
difficult waking up or confused demeanour
severe abdominal pain
rash with bleeding or bruising (hemorrhagic rash)
Also, be sure to let your doctor know if any of these complications occur:
The rash spreads to one or both eyes.
The rash gets very red, warm or tender, indicating a possible secondary bacterial skin infection.
Anyone in the household is immune deficient or younger than 6 months old.
Chickenpox and Shingles
If you've had chickenpox, you're at risk of another disease caused by the varicella-zoster virus called shingles. After a chickenpox infection, some of the varicella-zoster virus may remain in your nerve cells. Many years later, the virus can reactivate and resurface as shingles (a painful band of short-lived blisters). The virus is more likely to reappear in older adults and people with weakened immune systems.
Shingles can lead to its own complication, a condition in which the pain of shingles persists long after the blisters disappear. This complication, called postherpetic neuralgia, can be severe.
A shingles vaccine (Zostavax) is available and is recommended for adults age 60 and older who have had chickenpox.