Shingles (Herpes Zoster)
Herpes zoster, also known as shingles, is caused by the return of a chickenpox infection from latently infected nerve cells in the spinal cord or brain. It begins as a painful sensation which is often mistaken for a musculoskeletal injury. It is soon followed within one or two days by a red, blistering unilateral (one-sided) rash distributed to the skin supplied by a sensory nerve (a dermatome). Zoster tends to occur most often in the elderly and can be prevented with a vaccination. Treatment with antiviral drugs within 48 hours of the onset of the eruption limits the development of a persistent, severe pain (neuralgia) at the site of the eruption.