Chickenpox used to be a very common infection in the US. In the early 1990s, about four million Amercians were getting chickenpox and over 10,000 required hospitalization. That dramatically decreased after the vaccine became available in 1995. Routine childhood immunization includes the vaccine against chickenpox, and adults have access to a vaccine for shingles.
Chickenpox causes and risk factors
Chickenpox is caused by the varicella-zoster virus (VZV), and mostly affects children under the age of 10. Chickenpox can be transmitted through direct contact with the rash, but more often is transmitted through inhaling air droplets from an infected person who may cough or sneeze.
The risk of catching chickenpox is higher in children, because chickenpox is mostly a childhood disease. It is also very contagious, and spreads quickly though schools. If one person has chickenpox, up to 90% of the people close to the infected person, and who are not immune will likely become infected.
Adults who didn’t have chickenpox during childhood, those who didn’t receive the vaccine or individuals working in childcare or schools are also more likely to get the infection. Most people develop long-life immunity after an infection, and getting chickenpox more than once happens rarely. The same varicella-zoster virus is also responsible for a painful skin rash called shingles in adults.
The most common chicken pox symptoms and signs in children are a rash, low fever and malaise (tiredness). The rash is extremely itchy, starts on the back, chest and face then spreads over the entire body.
The rash goes through three phases. First, there are small raised pink-reddish bumps which turn into small blisters filled with fluid, and later become crusts and scabs. A person with the infection may have all three phases at the same time.
Teenagers and adults may experience nausea, muscle pain, lack of appetite and headaches before the rash develops.
Chickenpox illness typically lasts four to seven days. The incubation period is 10 to 21 days. A person is considered infectious for one to two days before the rash and another four to five days after the rash develops.
Severe cases of chickenpox can cause extensive rash over the entire body, and even form in the eyes, throat or vagina.
Possible complications of chickenpox include bacterial skin infections, dehydration, pneumonia, and inflammation of the brain. In very rare cases, chickenpox can be fatal.
If women get infected during early pregnancy, there is a risk their baby may have low birth weight and changes affecting the lungs. If the mother catches chicken pox right before birth, the baby may develop a severe infection.
Shingles are a late complication of chickenpox, usually affecting older adults. The virus remains dormant in the nerve cells and can reactivate later on in life.
Shingles also cause a characteristic rash with blisters, usually as a single strip around one side of the torso. The affected area is painful and sensitive to touch, and may be associated with numbness, tingling or a burning sensation. Some people develop pain that persists for a long time after recovering from shingles.
Adults with shingles can transmit the virus to individuals who never had chickenpox or have never been vaccinated against chickenpox. Shingles is transmitted similarly to chickenpox: through breathing in respiratory droplets loaded with the virus, or from direct contact with blisters.
Chickenpox is usually a clinical diagnosis, based on the characteristic rash, with skin lesions found in all three phases: bumps, blisters and crusts. A history of being exposed to another person who has the rash is another clue.
There are specific lab tests available such as the Tzanck smear, fluid culture and serologic testing, but these tests are rarely needed to confirm the diagnosis.
Most cases of chickenpox are mild in children, and the infection can be treated with home remedies to manage skin itchiness, including calamine lotion, a cold bath with oatmeal or baking soda, or over-the-counter antihistamine drugs (such as Benadryl).
Parents should not give children and teenagers Aspirin during chickenpox infections, because it can lead to Reye syndrome, a rare but serious condition that causes swelling in the liver and brain. Advil (ibuprofen) should be avoided as well during this infection due to potential risk of serious bacterial skin infections or tissue damage. Tylenol (acetaminophen) can be used to manage fever.
Parents should call their healthcare provider if their child has a temperature higher than 102 F/38.9 C or lasts longer than four days.
Seek medical treatment if the rash becomes very red, painful and is leaking pus (a sign of bacterial infection) or if other symptoms like confusion, stiff neck, severe vomiting or shortness of breath develop.
Doctors may recommend antiviral drugs to those who are at risk to develop chickenpox complications. Zovirax is an antiviral drug that may help reduce severity of the symptoms if it is taken within one day after the rash develops. Varicella-zoster immune globulin may be recommended in individuals with weak or compromised immune systems.
Chickenpox complications are treated as needed, and in some cases, the infected individuals may require hospitalization. Antibiotics are recommended for bacterial skin infections and pneumonia. Antiviral drugs are used for encephalitis.
Chickenpox prevention is widely available in the US.
The chickenpox vaccine (Varivax) is recommended in the US for children at age 12 to 15 months and a second dose at age four to five, as part of the childhood vaccination. Older children and adults who never had chickenpox or did not receive the vaccine but are at risk to catch the infections are also good candidates for the vaccine.
Chickenpox vaccine is not FDA-approved for pregnant women, individuals who take immunosuppressant drugs or who have HIV or for individuals who have allergies to certain ingredients in the vaccine.
Shingrix is the shingles vaccine, currently recommended for adults who have had chickenpox and are aged 50 or older.
According to the Centers of Disease Control and Prevention (CDC), breakthrough chickenpox can happen, but the person usually experiences milder symptoms, fewer or even no blisters at all, very little fever or no fever at all, and the duration of illness tends to be shorter.