The rash caused by chickenpox causes red spots on the skin and an itchy rash, notes the Centers for Disease Control and Prevention. The rash eventually develops fluid-filled blisters that itch and scab over. The rash appears initially on the face, back and chest before spreading to the rest of the body, including the genitals, eyelids and mouth.
One to two days before the chickenpox rash appears, symptoms of chickenpox occur, notes the CDC. These include high fever, headache, tiredness and loss of appetite. The illness caused by chickenpox usually lasts from five to 10 days. Anyone who has never had chickenpox before or who never received the chickenpox vaccine is susceptible to the condition. Even in those people vaccinated against chickenpox, as many as 30 percent still develop the condition.
The symptoms of chickenpox usually commence around 14 to 16 days after exposure to another person with the illness, notes WebMD. Once the red spots characterizing the condition occur, it takes one to two days for them to blister, burst, dry and crust over. New spots appear on the skin every day for up to a week.
After all of the blisters crust over, the affected person can return to work or school, reports WebMD. From the onset of symptoms to the crusting over of all blisters generally runs a course of 10 days.