Herpes Zoster, commonly called Shingles, is characterized by a painful rash with blisters. It results from reactivation of the dormant varicella-zoster virus, also known as chickenpox, that reactivates within sensory ganglia.

The painful rash is associated with an involved nerve root and its associated cranial or spinal nerve dermatome that occurs 3-5 days after transmission of the virus. It will usually only be present on one side of the body because it typically will not cross the midline. However, it can affect both sides of the body at different dermatome levels. Patients will typically experience 1-2 days of pain, itching, and hyperesthesia before the skin lesions are noticed.