Postherpetic neuralgia (PHN)

Herpes zoster (shingles) is an infectious disease caused by the varicella-zoster virus. Following the active phase of chicken pox and the crusting of skin lesions the virus spreads to the spinal and cranial ganglia and the posterior horns of the spinal cord, where it can stay dormant for many years. In immunocompromised patients, especially cancer patients, the virus can undergo reactivation to produce herpes zoster. The average incidence of herpes zoster is 4 per 1000 cases and rapidly increases with age and the lifetime prevalence is estimated at 10–20%. The predominating symptom of the acute phase of the disease is burning pain accompanied by abnormal skin sensation. The skin lesions in the form of vesicles usually heal within 3–5 weeks, unless a secondary bacterial infection ensues. After the skin lesions have healed, the pain may persist in some patients (9–14%) in the form of a chronic pain syndrome of various severity, usually unilaterally within one or several spinal dermatomes or the trigeminal nerve area. The first part of the paper discusses the pathomechanism, epidemiology, location, clinical manifestations and management of the acute phase of the disease. The second part provides a detailed discussion of the pathomechanism, risk factors, prevention and management of persistent postherpetic neuralgia according to evidence-based medicine, presenting the current state of knowledge on herpes zoster and postherpetic neuralgia. Over the years, the effectiveness of treatment of persistent postherpetic neuralgia has been gradually improving, mainly as a result of the currently available medication (antidepressants + gabapentinoids + topical medication + opioids) and the increasing understanding of the pathomechanism of this condition.Herpes zoster (shingles) is an infectious disease caused by the varicella-zoster virus. Following the active phase of chicken pox and the crusting of skin lesions the virus spreads to the spinal and cranial ganglia and the posterior horns of the spinal cord, where it can stay dormant for many years. In immunocompromised patients, especially cancer patients, the virus can undergo reactivation to produce herpes zoster. The average incidence of herpes zoster is 4 per 1000 cases and rapidly increases with age and the lifetime prevalence is estimated at 10–20%. The predominating symptom of the acute phase of the disease is burning pain accompanied by abnormal skin sensation. The skin lesions in the form of vesicles usually heal within 3–5 weeks, unless a secondary bacterial infection ensues. After the skin lesions have healed, the pain may persist in some patients (9–14%) in the form of a chronic pain syndrome of various severity, usually unilaterally within one or several spinal dermatomes or the trigeminal nerve area. The first part of the paper discusses the pathomechanism, epidemiology, location, clinical manifestations and management of the acute phase of the disease. The second part provides a detailed discussion of the pathomechanism, risk factors, prevention and management of persistent postherpetic neuralgia according to evidence-based medicine, presenting the current state of knowledge on herpes zoster and postherpetic neuralgia. Over the years, the effectiveness of treatment of persistent postherpetic neuralgia has been gradually improving, mainly as a result of the currently available medication (antidepressants + gabapentinoids + topical medication + opioids) and the increasing understanding of the pathomechanism of this condition