Chickenpox is caused by the varicella-zoster virus. This is the same virus that causes shingles. You can't get shingles unless you have had the chickenpox. Herpes zoster or shingles is a local manifestation of recurrent infection with the chickenpox virus. With shingles, vesicles erupt on the skin along a nerve, often along the chest wall.
Shingles is extremely painful along the nerve it effects.
The condition occurs primarily in older adults. Chickenpox is a highly contagious, itchy, uncomfortable infection that is spread through droplets from the nose and throat of the infected person. It shows up about 10 to 20 days after exposure to the virus and ususally lasts about 4 days to a week. The rash is superficial and appears first on the chest, abdomen and back, gradually extending to other parts of the body. The rash goes through a series of stages, beginning as a red bump, making a blister then erupting with fluid and then making a scab.