Shingles is an infection caused by the varicella-zoster virus, which is the same herpes virus that causes chickenpox. Shingles occurs in people who have had chickenpox and is a reactivation of the dormant varicella-zoster virus. The disease generally affects the elderly, although it occasionally occurs in younger and/or immunodeficient individuals. CLL patients fall into the latter category, and for this reason, they are more prone to reactivation of the varicella-zoster virus. It is not possible to catch shingles from somebody who has it. A person can only get shingles by having chicken pox earlier in life. However, an adult with shingles can cause a person who has not had chicken pox to get chicken pox.

The first sign of shingles is usually a tingling feeling, itchiness, or stabbing pain on the skin. This progresses to a rash that appears as a band or patch of raised dots on the side of the trunk or on the face. The rash develops into small, fluid-filled blisters, which begin to dry out and crust over within several days. Shingles can be very painful and itchy but is not generally dangerous to healthy individuals. However, people with shingles on the upper half of the face should seek medical attention immediately as the virus may cause serious damage to the eyes. The rash and pain associated with shingles usually disappear within 3 to 5 weeks, although, the pain can persist much longer and be quite intense. The pain that continues after the rash from shingles has healed is called, postherpetic neuralgia (PHN).

Most people who have shingles have only one occurrence of the disease in their lifetimes; however, individuals with impaired immune systems may suffer repeated episodes. Treatment for shingles includes antiviral drugs such as acyclovir (Zovirax). The severity and duration of an attack can be significantly reduced by immediate treatment.