What is shingles?
Shingles is an infection caused by the varicella zoster virus (VZV) that can cause nerve inflammation and intense pain, a reddened rash, and blisters (vesicles) that break open and crust over before slowly resolving. The rash and pain subside within a few weeks in most cases, but some of those affected may have severe pain that lingers for months or even years. VZV causes both shingles and chickenpox. When a person is first exposed to VZV, usually in childhood, they develop chickenpox, a common highly contagious primary systemic infection that causes multiple "crops" of vesicles in multiple locations and is passed from person to person through direct contact with fluid from blisters or coughing or sneezing. Once the chickenpox has resolved, the virus becomes dormant, persisting in a latent form at the base of sensory nerve cells near the spinal cord and brain. Normally, the body's immune system maintains this latency and produces sufficient VZV antibodies to protect against future exposures.
Later in life, typically decades later, and/or when a person's immune system becomes weakened, such as with an organ transplant, cancer Treatment, or HIV/AIDS, the virus can re-activate and cause shingles. VZV begins to reproduce again and moves outward along the length of one or more sensory nerves to the surface of the skin. Characteristic shingles Symptoms typically occur in a ribbon or band on one side of the trunk, face, or arm. This band of lesions corresponds to the section of skin (dermatome) that the affected nerve serves. Shingles is less contagious than chickenpox, but the virus may be passed to another person through contact with an open vesicle. The person exposed will only become infected if they have not been previously exposed to a VZV infection or have not been vaccinated – and they will develop chickenpox, not shingles.
Almost all adults in the U.S. have had chickenpox and about one million people a year get shingles. Also called herpes zoster, shingles is currently estimated to affect about 1 in 3 people during their lifetime, with the incidence rising with age. Shingles is most common in those over 60 years of age and in those with weakened immune systems. Although most people will only have shingles once, the virus can potentially re-activate and cause shingles again. Those with weakened immune systems may have difficulty regaining and maintaining virus latency. A baby that is born with chickenpox is at an increased risk for developing pediatric shingles. This is a rare event that sometimes occurs when a woman has chickenpox, or even more rarely develops shingles, during her pregnancy.