The disease most often affects children, and most of those children will have mild symptoms. But some groups of people — including teenagers, adults, and children with certain health conditions — are at greater risk for severe symptoms and complications from a chickenpox infection. Complications from chickenpox can take many forms. They range from mild secondary skin infections to life-threatening brain inflammation. Chickenpox in a woman who is pregnant can also cause serious complications in the baby, especially if the woman has the infection early in her pregnancy or shortly before giving birth.

Who Is at Risk for Chickenpox Complications?

Anyone who has had chickenpox or has been vaccinated against it has a very low risk of developing chickenpox or its potential complications. In addition, most children who get chickenpox won’t experience any severe symptoms or complications. But people outside the typical childhood age range, as well as children and adults with certain health conditions, are more likely to experience worse symptoms and possibly complications. Groups with a higher risk for chickenpox complications include:

InfantsTeenagersAdultsPregnant womenPeople with an impaired immune system (due to a health condition or medical treatment)People who take steroid medication, including children with asthma (1,2)

While these groups are significantly more likely to develop chickenpox complications, children who don’t fall into any of these categories can develop them too. So any child with chickenpox should be monitored closely by a parent or caregiver to watch for signs of the disease worsening.

Possible Complications of Chickenpox

Complications of chickenpox may include the following conditions:

Bacterial infection (usually affects skin and soft tissues)Pneumonia (lung infection)Brain infection or inflammation (encephalitis)Liver inflammationDehydrationBleeding problemsSepsis (blood infection)Reye syndrome, in people who take aspirin (a potentially dangerous drug for chickenpox) (1,2,3)

Some people develop complications that are severe enough to require hospitalization. In especially severe cases, these complications can be deadly. In fact, despite a large reduction in chickenpox-related hospitalizations and deaths since vaccination was widely adopted, deaths in healthy children and adults who weren’t vaccinated continue to occur in the United States, according to the Centers for Disease Control and Prevention (CDC). (4) Pneumonia occurs in about 1 in 400 adults who develop chickenpox. (3) It rarely occurs in children with a normal immune system. Typical symptoms of pneumonia include coughing, fever, and difficulty breathing. Brain infection or inflammation occurs in only about 1 to 2 out of 1,000 cases of chickenpox. (3) It can cause unsteadiness while walking, a headache, dizziness, confusion, and even seizures. In adults, this complication can be life-threatening. Reye syndrome is a rare but very serious chickenpox complication involving brain and liver inflammation. It usually occurs after a child with the infection is given aspirin. Because of this risk, aspirin is never recommended for chickenpox. (3)

Health Conditions That Raise the Risk of Chickenpox Complications

Certain patterns of chickenpox complications are often seen in people with the following health conditions:

Weakened Immune System

A person with a weakened immune system — because of a health condition or medical treatment — is at risk for a serious condition called visceral dissemination, in which internal organs are infected by the chickenpox virus. (5) An infection affecting internal organs can lead to pneumonia, hepatitis (liver inflammation), brain swelling, and a condition called disseminated intravascular coagulation, which affects the blood’s ability to clot. (6) People in this group may also have more chickenpox sores, and they may be sick for longer than is typical. New sores may develop for over a week, and they may appear on the palms of your hands or soles of your feet.

HIV or AIDS

When children with HIV get chickenpox, new sores can develop for weeks or even months. Their chickenpox sores may be normal, or they may turn into ulcers that don’t heal and cause severe discomfort. Chickenpox complications are more likely in people with HIV if they have low CD4 counts (a measure of immune system function). Another possible complication in children or teenagers with HIV is retinitis, in which the back wall of your eye (retina) becomes inflamed. Some studies have suggested that complications involving internal organs are less common in children with HIV than in other people with a weakened immune system. (5)

Pregnancy

Chickenpox infection in the first or early second trimester of pregnancy can cause a number of problems in newborns, including low birth weight and limb abnormalities. Chickenpox that develops in a pregnant woman in the week before giving birth, on the other hand, can cause a life-threatening infection in her newborn. While chickenpox in newborns used to carry a mortality rate of about 30 percent, advances in treatment have reduced this rate to about 7 percent, according to the CDC. Pregnant women are also at greater risk for complications, such as pneumonia, that may be severe or life-threatening. Some studies suggest that pneumonia is more likely when a pregnant woman gets chickenpox during the third trimester. (1,3,5)

How to Spot the Signs of Chickenpox Complications Early

While it’s a good idea to see your doctor whenever symptoms of chickenpox occur, it’s especially important to follow up if you notice any of the following signs of potential complications:

A fever lasting more than four days, or that rises above 102 degrees F (38.8 degrees C)Severe cough or trouble breathingA chickenpox sore that leaks pus (a thick, yellowish fluid) or becomes very red or tenderA rash that spreads to one or both eyesDizziness or confusionRapid heartbeatLoss of muscle coordination, including difficulty walkingVomitingTremors (severe shaking)Stiff neckSevere headacheUnusual drowsiness or trouble waking upDifficulty looking at bright lights (1,7)

Shingles: Reactivation of the Varicella Virus

Years after a case of chickenpox is resolved, the virus can return and cause symptoms again — a condition known as shingles. While shingles isn’t typically viewed as a complication of chickenpox due to its extremely delayed onset, it’s important to be aware of the condition so that if it develops, you can seek proper treatment. (1,3) The CDC recommends that healthy adults age 50 and older get two doses of the newer vaccine against shingles, called Shingrix, two to six months apart, to prevent shingles. (8)