Postherpetic Neuralgia: Mechanisms, Risk Factors, and Stratified Management—A Narrative Review

BACKGROUND: In 2020, an estimated 14.9 million herpes zoster (HZ) cases occurred worldwide among adults aged ≥ 50 years; this number is projected to rise to 19.1 million by 2030. Postherpetic neuralgia (PHN), the most common complication of HZ, develops in 5% to > 30% of patients with HZ. Poorly managed PHN may cause persistent pain, functional impairment, psychological distress, and, in severe cases, suicide. This review summarizes the current evidence on PHN and proposes a tiered management framework. METHODS: PubMed and Web of Science were searched for PHN-related articles published from January 2011 to December 2025, with reference-list screening. Studies were selected by clinical relevance and design. Management strategies were tiered by guideline support, regulatory approval, and PHN-specific efficacy and safety evidence. RESULTS: Pathogenesis involves viral reactivation, peripheral and central sensitization, and genetic modulation. Major risk factors include older age, severe acute pain, extensive rash, craniofacial/thoracic involvement, immunocompromise, comorbidities, and treatment delay. Management of PHN is tiered: Tier 1 treatments include gabapentinoids, the 5% lidocaine patch, tricyclic antidepressants, duloxetine, and the 8% capsaicin patch; Tier 2 treatments include botulinum toxin type A injections, pulsed radiofrequency, and temporary spinal cord stimulation (tSCS); and Tier 3 options include opioids and neuromodulation. CONCLUSIONS: PHN remains the most common and therapeutically challenging complication of HZ. Although a stratified framework for PHN management has been proposed, it still requires validation in clinical practice and further refinement to support more effective individualized treatment.