5 Potentially Serious Complications of Chickenpox Infection

Childhood disease can often lead to more serious illness

Girl with Chickenpox in Isolation Room
Colleen Butler / Getty Images

Chickenpox (varicella) is typically a benign, self-limiting disease. However, in some cases, it can lead to serious complications immediately following or even years after an outbreak. In fact, around 14,000 people are hospitalized in the U.S. each year as a result of the disease, of which around of hundred will die.

Other long-term complications can affect as many as third of all adults, with the highest risk seen in seniors and people with compromised immune systems.


After a person is infected with chickenpox, the virus is not completely eliminated from the body. Instead, it travels up the nerves to nerve branching points called ganglia, where it stays in an inactive, latent form for many years.

Certain triggers can force the dormant virus to suddenly reactive, often decades after the initial infection. When this happens, the virus will travel back down the nerve to the skin, causing painful, burning skin blisters along the nerve branch. The condition is known as shingles (varicella zoster) and is most commonly seen in adults over the age of 50.

According to the Centers for Disease Control and Prevention (CDC), one out of three Americans will experience at least one episode of shingles over the course of a lifetime.

Bacterial Infection

The most common complication of varicella is a secondary bacterial infection of the chickenpox lesions. The bacteria most likely to cause these infections are Staphylococcus aureus and Streptococcus pyogenes, resulting in such complications as impetigo, furunculosis, cellulitis, erysipelas, and lymphadenitis.

While these infections are mostly superficial (and readily treated with antibiotics), there is a risk that the bacteria can spread (disseminate) into the bloodstream, leading to a condition called bacteremia. People with bacteremia are at risk of not only bacterial pneumonia but other potentially serious infections including meningitis, arthritis, osteomyelitis, sepsis, shock, or even death.

Neurologic Complications

The second most common complication of chickenpox involves the neurological system. One of the more serious disorders is a childhood condition called acute cerebellar ataxia, which can cause fever, progressive irritability, difficulty walking, and speech impairment. Symptoms can persist for days or even weeks but usually resolve on their own.

Another notable complication is varicella meningoencephalitis, which causes sudden delirium, seizures, headache, sensitivity to light, and neck pain. It tends to affect immune-compromised individuals, including those with later stage HIV infection and may require intravenous treatment with antiviral drugs.

Respiratory Complications

Varicella pneumonia is the leading cause of varicella-related illness and death in adults. The disease is the result of the dissemination of the virus through the bloodstream, causing infection within the lung. Approximately one in every 400 adults who develop chickenpox will be hospitalized as a result of this illness. 

Risk factors include:

  • contracting chickenpox at an older age
  • a rash outbreak with a larger number of lesions
  • a compromised immune system
  • pregnancy (especially in the third trimester)
  • smoking
  • chronic obstructive pulmonary disease (COPD)

Liver Complications

A common complication of chickenpox is transient hepatitis (temporary inflammation of the liver). This does not usually cause symptoms and tends to get better on its own.

However, in some cases, it can lead to Reye's syndrome, a potentially life-threatening condition primarily caused by the administration of aspirin during a viral infection. The incidence of Reye's syndrome has dropped dramatically in recent years as parents have been increasingly advised against treating childhood fevers with aspirin.