Shingles is a viral infection caused by the varicella-zoster virus, the same virus that causes chickenpox. After a person recovers from chickenpox, the virus can remain dormant in the nervous system and may reactivate later in life, leading to shingles. It typically presents as a painful rash that develops on one side of the body, often accompanied by itching, burning, or tingling sensations. The rash usually forms blisters that eventually crust over and heal within a few weeks. Shingles can occur in anyone who has had chickenpox, but it is more common in older adults and those with weakened immune systems. Vaccines are available to help reduce the risk of developing shingles.