What is the primary cause of shingles?

The primary cause of shingles is the varicella-zoster virus, which is the same virus that causes chickenpox. After a person recovers from chickenpox, the virus does not completely leave the body; instead, it remains dormant in the nerve cells. Years later, the virus can reactivate, leading to shingles, which is characterized by a painful rash typically confined to one side of the body.

Understanding the nature of this virus is crucial for recognizing the distinct manifestations of shingles compared to the diseases caused by other viruses. For instance, while the herpes simplex virus is responsible for cold sores and genital herpes, it is not related to shingles. The influenza virus is responsible for the flu, and the human immunodeficiency virus (HIV) leads to AIDS, neither of which are linked to the reactivation that causes shingles. This highlights the importance of varicella-zoster as the specific pathogen associated with this condition.