Post-herpetic neuralgia (PHN) is a chronic pain syndrome associated with the reactivation of a primary infection with varicella zoster virus (chicken pox), which leads to a chronic infection of the dorsal root ganglia. Under various clinical circumstances, including immunosuppressive diseases or treatments and certain cancers, reactivation of the infection can occur in adults as shingles. Other factors such as psychological distress and stressful life events also appear to play a role in the onset of shingles and the development of PHN. The most common risk factor for shingles and its potential sequela, PHN, is advanced age. For a significant number of patients, the pain following healing of shingles can persist for months to years; this pain is classified as PHN if it persists longer than 3 months. PHN often leads to depression, disrupted sleep, decreased functioning and increased healthcare utilization. Prompt use of antiviral therapy appears to reduce the period of pain following an episode of shingles by about half and may possibly reduce the overall incidence of PHN. Damage to a variety of neurologic pathways as a result of herpes zoster reactivation suggests that intervention with multiple agents having divergent mechanisms of action is an appropriate treatment approach. Current treatment options aimed at relieving the symptoms of PHN include antidepressants, opioids, anticonvulsants and topical analgesics. It is important for the clinician to establish a baseline pain intensity and character as well as quality of life measures against which to judge the effectiveness of any treatment. This review article features a case study of a patient with PHN to illustrate current diagnostic and treatment approaches.
