Chickenpox (Varicella): Causes, Risk Factors, Symptoms, Treatment

Chickenpox (Varicella)

Chickenpox is also known as varicella infection. Chickenpox is an infection that causes an itchy skin rash. Most individuals are affected with varicella virus at a young age if they haven't received varicella vaccine. A single child with chickenpox can easily spread the infection to others. Chickenpox is much less common in today's world due to increased vaccination at a younger age. Generally, if an individual is affected with chickenpox, then the human body would develop immunity against the virus and the chances of getting re-infected are very low. However, if an individual is not vaccinated then they could get varicella infection/chickenpox at any age. Individuals who get affected by varicella infection in their adulthood become very sick. Hence, preventing it by getting vaccinated is the key.

If you develop a sudden onset of itchy skin rash with fluid-filled blisters and have not been vaccinated or exposed to Chickenpox, seek prompt evaluation from an Infectious Disease specialist or a General Practitioner in the Internal Medicine department.


Varicella infection/Chickenpox is caused by a member of the Herpes-virus family called Varicella-zoster virus(VZV). This same virus also causes shingles in adults. Varicella infection/Chickenpox is caused most commonly in the late winter and spring seasons.

Risk Factors

Understanding the risk factors associated with Chickenpox is crucial in identifying individuals who may be more susceptible to this infection. By recognizing these risk factors, individuals can take proactive measures to prevent the spread of disease and Immune-compromised individuals e.g. individuals with asthma, lupus, hematopoietic stem cell transplant individuals(within 2 years of transplantation or on immune-suppressive therapy). The risk of infection is higher in HIV or AIDS with low CD4 counts, however, individuals on anti-retroviral therapy and high CD4 counts had a lesser risk of developing varicella infection. People receiving immunosuppressive therapy (individuals receiving high-dose steroids, chemotherapeutic agents, and biologic agents) are at significant risk of getting varicella infection/chickenpox upon exposure. Pregnant women who are affected with varicella and at increased risk for complications like pneumonia. Few studies have shown that when pregnant women are affected with varicella infection in the first or early second trimester, the baby has a minute risk of developing congenital varicella syndrome, in which the baby may have abnormalities of eyes, limbs, brain; scarring of the skin, low birth weight. Premature infants born to susceptible mothers are at risk for varicella infection.


The classic symptom of varicella infection is a skin rash. Once infected, it may take 10-21 days to develop. Individuals affected with varicella infection may have fever, and weakness, prior to rash. Initially, it develops like a rash (a flat mark) different than the skin tone usually upon the chest area, back, and face, and then spreads over to the entire body later the rash develops into an elevated pimple-like bump filled with fluid and increase in size and form a vesicle (like dew drops on a rose petal). Vesicles will be formed all over the body like the trunk, face, scalp region, under the armpits, upper arms and lower legs, and inside of the mouth. More number of lesions are present in the back and chest area. Later these vesicles will break and form a crust and then form a scab in about 5-7 days. Symptoms also include stomach pain for 1-2 days, irritability, headache, decreased appetite, muscle or joint pain, cough, and runny nose.


Diagnosis is made by complete medical history and physical and skin examination. Signs of Varicella zoster infection are easily identified by the health care provider. However, in children, the rash is the initial sign for the onset of infection whereas, in adults, it presents with fever and generalized weakness for about 1-2 days before the onset of the rash. In a few cases, your health care provider may advise a few blood tests to check for Varicella zoster IgM levels.


Treatment of Varicella infection is determined by age of the individual, medical history, and extent of the condition. Generally, treatment involves: Ø Acetaminophen for fever and pain Ø Calamine lotion to relieve the itching Ø Antiviral medications like Acyclovir Ø Antibacterials in case of any skin infection (scratching would lead to secondary bacterial infections) Ø Increased fluid intake to prevent dehydration Ø Cool baths with added baking soda or uncooked oatmeal bath. Ø Varicella-zoster immune globulin is used as a prophylactic therapy in high-risk individuals after exposure to varicella and for the treatment of varicella.

Preventive Measures

Individuals who were affected with Varicella infection will be immune to it for the rest of their lives. However, the virus remains dormant (temporarily inactive) in the nerve tissue and may reactivate later in life resulting in herpes zoster infection called shingles which can be avoided by vaccination with Shingrix after 60 years of age. Varicella vaccine is given as a shot to children between 12 and 15 months old and a booster shot between 4-6 years of age. Children older than 6 years and younger than 13 years of age should get 2 doses of Varicella vaccine which is given 3 months apart. Shingrix (recombinant zoster vaccine) vaccine should be administered to immunocompetent adults ages 50 years or older and adults aged >19years who are immunodeficient or are going to be immune-suppressed due to a disease or therapy as a 2-dose series of 0.5ml each of about 2-6months apart (i.e. 0, 2-6months) Prevention: Varicella-zoster immune globulin is given to people who cannot receive varicella vaccine. Immune globulin can help prevent from developing or decreases the severity of the disease. Individuals for whom Varicella-zoster immune globulin is recommended: Ø Evidence of immunity of Varicella is unknown Ø Individuals who are exposed and are likely to develop an infection Ø Individuals who are at high risk of developing varicella/chickenpox infection. The varicella vaccine is contraindicated in pregnant women. Varicella infection is highly contagious, the virus spreads quickly from one person to another either by direct contact or inhalation of aerosols from vesicular fluid of the skin lesions. A person infected with Varicella virus is considered to be contagious 1-2 days prior to the onset of rash to until the lesions have crusted completely.

Do's & Don’t's

Knowing the do's and do n'ts can make a significant difference in the recovery process. By following simple methods, patients can help reduce symptoms, promote healing, and also prevent further complications. 

Do's Don't 
Seek medical guidance.  Do not scratch over the rashes; keep fingernails trimmed to minimize scratching and prevent the spread of infection. 
Apply calamine lotion over the rash area to cool the itching.  Do not break or poke the blisters; if a blister breaks accidentally, wash hands immediately with soap and water. 
Stay at home until all blisters have scabbed over to prevent spreading the infection. Do not peel off the scabs on your skin.
Take a cool bath with baking soda or uncooked oatmeal to relieve itching.  Avoid spicy and acidic foods if blisters form inside the mouth, as they can cause inflammation and discomfort.

If you develop a sudden onset of itchy skin rash with fluid-filled blisters and have not been vaccinated or exposed to Chickenpox, seek prompt evaluation from an Infectious Disease specialist or a General Practitioner in the Internal Medicine department.

Frequently Asked Questions
Chickenpox, also known as varicella, is a highly contagious viral infection caused by the varicella-zoster virus (VZV). It primarily affects children but can also occur in adults who haven't been previously infected or vaccinated against it.
Chickenpox is highly contagious and spreads through direct contact with the rash or respiratory droplets from an infected person. It can also spread through touching contaminated objects.
The typical symptoms of chickenpox include an itchy rash that starts as red spots and progresses into fluid-filled blisters before crusting over, fever, headache, fatigue, and loss of appetite.
The incubation period, i.e., the time from exposure to the virus to the appearance of symptoms, is usually around 10 to 21 days.
Yes, there is a vaccine available for chickenpox. The varicella vaccine is highly effective in preventing the infection or reducing its severity if a vaccinated person does get infected.
It's rare but possible to get chickenpox more than once. However, having chickenpox once typically provides lifelong immunity in most people.
Complications can include bacterial infections of the skin, pneumonia, encephalitis, and in certain cases, it can lead to more severe issues, especially in individuals with weakened immune systems.
Treatment usually involves managing symptoms. This includes taking antihistamines to relieve itching, using calamine lotion to soothe the skin, and possibly taking antiviral medications in certain cases. It's important to avoid scratching to prevent secondary infections.
A person with chickenpox is contagious from about 1 to 2 days before the rash appears until all the blisters have crusted over, usually around 5 to 7 days after the rash begins.
If you've had chickenpox before or have been vaccinated, you're unlikely to catch it again. In most cases, being around someone with chickenpox shouldn't pose a risk, but it's advisable to consult with a healthcare professional for guidance.
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