Clinical Definition

Shingles is an infectious disease caused by the varicella-zoster virus (VZV). The condition causes inflammation of the ganglia and is characterized by a skin rash and postherpetic pain. Shingles usually develops after a reactivation of the varicella-zoster virus, due to a primary chickenpox infection.

In Our Own Words

Shingles is a viral infection that affects the nerves and causes a painful rash. The rash usually follows a pattern the patient’s doctor can recognize, along “dermatomes,” or segments of the body that correspond to certain nerves. The varicella-zoster virus causes both chickenpox and shingles. In people who have had chicken pox, the virus remains in the body in certain nerve cells even after they have recovered. It is inactive for years and does not cause illness. Shingles develops when the virus becomes active again.

Although it is not completely understood why the virus sometimes activates, it is more likely to occur in adults over the age of 60 and in people who have a weakened immune system. A shingles vaccine is available.