Postherpetic neuralgia is a condition involving chronic pain that occurs after shingles and persists for more than three months after the rash has healed. Shingles is caused by the varicella zoster virus, which also causes chickenpox in childhood. After recovery, the virus remains dormant in the nerve roots and can later become reactivated, causing a painful rash with blisters in a band-shaped area on the skin, typically on the arms, legs, or face.

The symptoms of postherpetic neuralgia primarily consist of burning, stabbing, and shooting pain, and the skin in the affected area can be extremely sensitive. Even light touch, such as clothing brushing against the skin, can trigger pain. The intensity of the pain can vary greatly and may last for several months or years for some people, while for others, it gradually diminishes.

The cause of the persistent pain is permanent nerve damage caused by shingles. This nerve injury results in incorrect and overactive pain signals being sent to the brain, which are perceived as pain in the area where the rash previously appeared. The damaged nerves may also become hypersensitive, making normal touch feel painful.

Postherpetic neuralgia primarily affects older adults, and the risk increases with age. Studies show that up to 10% of people who have had shingles experience pain after six months. For those over 80 years old, the risk can be as high as 35%. The risk is also higher if the initial rash was very painful.

The diagnosis is based on persistent pain in a skin area where shingles previously occurred. The pain is not contagious and is not a sign of active viral infection. Vaccination against shingles can reduce the risk of developing both shingles and the subsequent nerve pain.