Symptoms

The incubation period—the time from exposure to the chickenpox virus until you develop symptoms—is usually 14 to 16 days but can be from 10 to 21 days. The first symptoms of chickenpox infection include:

• A fever of 100.4°F (38°C) to 103°F (39.4°C).
• Feeling sick, tired, and sluggish.
• Little or no appetite.
• Headache and sore throat.

The first symptoms are usually mild in children, but they can be severe in teens and adults. These symptoms may continue throughout the illness.

About 1 or 2 days after the first symptoms of chickenpox appear, an itchy rash develops. During a typical course of chickenpox:

• Red or swollen spots or bumps appear and turn into pimplelike blisters filled with clear or cloudy fluid.
• The blisters break open, often leaking fluid.
• A dry crust forms over the broken blisters as they heal.

Chickenpox is most contagious from 2 to 3 days before the rash develops until all the blisters have crusted over.

Other conditions may cause a similar rash.