Varicella (chickenpox) is caused by the varicella-zoster virus (VZV), which also causes shingles. The virus spreads through the body into the skin causing rashes to appear.
Varicella may begin with cold-like symptoms, followed by a high temperature and a very itchy, blister-like rash. Clusters of spots appear over 3–5 days, mostly on the trunk of the body with some on the limbs. Symptoms vary in severity from person to person. It is possible to have chickenpox and have no symptoms.
You can only get shingles if you have previously had varicella and the virus is reactivated in your body. Shingles symptoms in older people usually start with a pain in the area of the nerve which is affected — often the chest. A rash of blisters then appears in the affected area, usually only on one side of the body. The rash usually lasts around seven days but the pain can last for longer. Someone with shingles can give the virus to someone who hasn’t had chickenpox and is not immune, but not the other way around: a child with varicella cannot give shingles to another person.