Many children with chickenpox are sick with headache, fever, stomach ache, and also a loss of appetite, for a day or two before breaking out in the chickenpox rash, and these symptoms usually last for 2 to 4 days after breaking out.
The average child will develop 250 to 500 small, itchy, fluid-filled blisters over red spots on the skin. The blisters often appear first on the face, torso, or scalp and spread from there to the arms and legs. Blisters on the scalp are found in approximately 80% of cases. This clinches the diagnosis.
The rash begins as small red dots on the face, scalp, torso, upper arms and legs; progressing over 10–12 hours to small bumps, blisters and pustules; followed by umbilication and the formation of scabs.
After a day or two, the blisters become cloudy and then become sores which develop a scab. At the same time, new crops of blisters continue to develop.
Chickenpox often appears in the mouth, in the vagina, and on the eyelids.
Because watery nasal discharge containing live virus usually precedes both exanthem (external rash) and enanthem (oral ulcers) by 1 to 2 days, the infected person actually becomes contagious one to two days before recognition of the disease. Contagiousness persists until all vesicular lesions have become dry crusts (scabs), which usually entails four or five days, by which time nasal shedding of live virus ceases.
Children suffering from other skin problems, such as eczema, may get more than 1,500 chickenpox blisters.
In most cases, chickenpox will not leave scars unless they become contaminated with bacteria from scratching.