Shingles, also known as zoster, herpes zoster, or zona, is a viral disease characterized by a painful skin rash with blisters involving a limited area. Typically the rash occurs on either the left or right of the body or face in a single stripe. Two to four days before the rash occurs there may be pain or tingling in the area. Otherwise there are typically few symptoms. The rash usually heals within two to four weeks; however, some people develop ongoing nerve pain which may last for months or years, a condition called postherpetic neuralgia. In those with poor immune function the rash may occur widely. If the rash involves the eye, vision loss may occur.Shingles is due to a reactivation of varicella zoster virus (VZV) within a person's body. Chickenpox is due to an initial infection with VZV. Once chickenpox has resolved, the virus may remain inactive in nerve cells. Risk factors for reactivation include older age, poor immune function, and having had chickenpox before 18 months of age. How the virus remains in the body or subsequently re-activates, is not well understood. Exposure to the virus in the blisters can cause chickenpox in someone who has not had it before but will not trigger shingles. Diagnosis is typically based on a person's signs and symptoms. Varicella zoster virus is not the same as herpes simplex virus; however, they belong to the same family of viruses.The shingles vaccine decreases the chance of shingles by about half in those between the ages of 50 and 80. It also decreases rates of postherpetic neuralgia, and if an outbreak occurs, its severity. After 80 the vaccine is still effective, just less so. It contains the same material as the varicella vaccine just at a higher dose. If shingles develops, antiviral medications such as aciclovir can reduce the severity and duration of disease if started within 72 hours of the appearance of the rash. Evidence does not show a significant effect of antivirals or steroids on rates of postherpetic neuralgia. Paracetamol, NSAIDs, or opioids may be used to help with the acute pain.It is estimated that about a third of people develop shingles at some point in their life. While more common among older people, children may also get the disease. The number of new cases per year ranges from 1.2–3.4 per 1,000 among healthy individuals to 3.9–11.8 per 1,000 among those older than 65 years of age. About half of those living to age 85 will have at least one attack, and less than 5% will have more than one attack. The disease has been recognized since ancient times. In Arabic its name means ""belt of fire"", while in Spanish it means ""small snake"", and in Hindi it means ""big rash"".