The incubation period—meaning the time between exposure and the appearance of chickenpox symptoms—is between 10 to 21 days, with an average of 14 days.

While children under 10 are most commonly affected by chickenpox (varicella-zoster virus, or VZV), older children and adults can get it if not previously exposed.

This article describes the frequent and rare symptoms of chickenpox, including potentially serious complications affecting the brain, nerves, skin, or lungs.

Frequent Symptoms of Chickenpox

Healthy people who become sick after being exposed to the varicella-zoster virus will develop a cluster of symptoms typical of any viral infection in addition to the telltale chickenpox rash.

Non-Rash Symptoms

Most non-rash symptoms last for a day or two, then disappear as the rash develops. These are often non-specific and easily mistaken for things like flu.

Common non-rash symptoms include:

Fever (usually mild, around 102 degrees, although it can go as high as 105) Malaise (a general feeling of unwellness) Headache Loss of appetite  Mild abdominal pain  Swollen lymph nodes

A person infected with VZV can be contagious during the first couple of days preceding the outbreak of the chickenpox rash.

Chickenpox Rash

The chickenpox rash usually appears first on the torso, scalp, and face, and then spreads to the arms and legs.

The rash is extremely itchy, but it’s important not to scratch. Scratching can lead to infection and leave behind an unsightly scar.

The number of spots a person with chickenpox gets can vary. The typical range is between 100 and 300. Adults and older kids usually develop more than younger children.

Each one starts as a 2- to 4-millimeter red bump (papule) with an irregular border. Within a short period of time, the papule fills with highly-contagious fluid and develops a characteristic “dewdrop” appearance. 

After eight to 12 hours, the fluid becomes cloudy and the tiny blister-like bumps (vesicles) erupt, leaving behind a crusty deposit that usually falls off after seven days.

Less Common Symptoms of Chickenpox

Less commonly, the chickenpox rash can cause lesions on mucous membranes in the eyes, mouth, and vagina.

On rare occasions, children who have been partially vaccinated or even fully vaccinated can come down with chickenpox anyway. This is referred to as breakthrough chickenpox.

The symptoms of breakthrough chickenpox tend to be milder and can easily be mistaken for bug bites or other common rashes.

The symptoms of breakthrough chickenpox include:

Fewer than 50 rashesFew or no vesicles (meaning there is less chance of infecting others)Low or no feverQuick recovery (often within three to five days)

Complications of Chickenpox

For people who are in good health, chickenpox is unlikely to lead to any serious issues. However, around 14,000 people are hospitalized in the United States each year as a result of chickenpox complications. For around 100 of them, chickenpox can be fatal.

Chickenpox complications can include bacterial infections that enter the skin due to scratching, neurological disorders, pneumonia, and shingles.

As many as a third of adults who get chickenpox are at risk of serious complications, especially people 65 and over and those with compromised immune systems.

Bacterial Infection

The most common complication of chickenpox is a secondary bacterial infection caused by Staphylococcus aureus or Streptococcus pyogenes. Secondary infections occur when bacteria enter the body through broken skin caused by a primary infection.

With chickenpox, this can lead to secondary infections such as:

Cellulitis Erysipelas (St. Elmo’s Fire) Furunculosis Impetigo Lymphadenitis

These infections are mostly superficial and easily treated with antibiotics. However, there is a risk that the bacteria can spread into the bloodstream, leading to a severe condition called bacteremia.

People with bacteremia are at risk of bacterial pneumonia, as well as other potentially serious infections like meningitis and sepsis.

Neurologic Complications

The second most common set of complications of chickenpox involves the nervous system. One of the more serious neurological disorders is a childhood condition called acute cerebellar ataxia.

Symptoms include fever, irritability, difficulty walking, and speech impairment, which can persist for days or even weeks. Fortunately, they usually resolve on their own without treatment.

Varicella meningoencephalitis is another potential neurological complication. This is the inflammation of the membranes that surround the brain and spinal cord.

Symptoms can include a headache, sensitivity to light, neck stiffness and pain, delirium, and seizures. People with compromised immune systems are most at risk, including those with advanced HIV. 

Pneumonia

Varicella pneumonia is the leading cause of VZV-related illness and death in adults. It develops when the virus travels to the lungs via the bloodstream, where it causes infection.

Risk factors include: 

Getting chickenpox at an older age A severe rash outbreak A compromised immune system Pregnancy (especially during the third trimester) Smoking and or having chronic obstructive pulmonary disease (COPD)

Shingles

After a person is infected with chickenpox, VZV is not completely eliminated from the body. Instead, it embeds itself in clusters of nerve cells called ganglia, where it remains dormant (inactive).

Certain triggers can cause VZV to suddenly reactivate, often decades after the initial infection. The consequence is a painful, blister-like eruption known as shingles (herpes zoster).

Shingles most commonly affect adults over 50. Vaccination against shingles can help prevent this complication.

When to See a Healthcare Provider

Chickenpox is an easily identifiable illness that a healthcare provider can often diagnose over the phone or a virtual visit. And, like most viral infections, it usually gets better on its own.

However, if you have signs of a secondary infection or other complications, call a healthcare provider immediately.

Symptoms of concern include:

Lesions that become increasingly larger and more painfulLesions that turn into ulcers or have a pus-like dischargeHigh fever with chillsLymph nodes in the neck that are tender to the touchRash that spreads to one or both eyesTrouble breathing and wheezingDifficulty swallowingSevere headache with neck pain and vision changesConstant, inconsolable crying in small children

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