Herpes zoster (shingles) is a reactivation of latent infection of varicella-zoster virus (VZV). Disseminated zoster most commonly affects immunocompromised patients and only rarely the immunocompetent population. Dissemination typically occurs 4-11 days after the onset of localized cutaneous disease. Dissemination may be confined to the skin or it may affect the viscera as well. It is estimated that cutaneous dissemination occurs in 10%-40% of immunocompromised patients affected by zoster.

Disseminated cutaneous herpes zoster is defined as more than 20 vesicles outside the primary and adjacent dermatomes. Cutaneous disease itself is not life-threatening; however, it is a sign of viremia. In severely immunocompromised patients, this viremia can lead to visceral involvement, which can be life-threatening. Visceral dissemination can precede cutaneous disease and has rarely been reported to occur without evidence of cutaneous disease. Visceral involvement can include the lungs, the liver, and the brain. Death is most commonly due to pneumonia.

Patients at highest risk for dissemination include those with lymphoproliferative malignancies, organ transplant recipients, patients with AIDS, and patients receiving systemic corticosteroids. Disseminated zoster may be an early clinical sign of underlying human immunodeficiency virus (HIV) infection in high-risk populations.

Postherpetic neuralgia (PHN), as in localized cutaneous zoster, is a known complication of disseminated zoster.