Does herpes zoster injure sensory nerves and contribute to persistent post-herpetic neuralgia?

Herpes zoster is not solely a skin eruption: varicella-zoster virus reactivation affects sensory ganglia, roots, and peripheral nerves. Persistent postherpetic neuralgia (PHN) is pain continuing after the eruption has healed and is best understood as a mixed neuropathic pain syndrome.

Neural injury and inflammation

• Human pathology strongly supports sensory-neural involvement during zoster, including dorsal-root or cranial-ganglion inflammation (ganglionitis), mononuclear inflammatory infiltration, hemorrhage, necrosis, and focal loss of ganglion neurons and nerve fibers.
• Sensory roots and peripheral nerves may show neuritis, demyelination, and axonal degeneration; fibrosis/scarring can follow. These changes provide a structural basis for sensory loss and neuropathic pain.
• In PHN, skin biopsies commonly show reduced intraepidermal nerve-fiber density on the affected side, consistent with loss of C-fiber and Aδ-fiber endings.

Persistent pain mechanisms

• Central sensitization is supported, particularly for brush-evoked/dynamic mechanical allodynia. Dorsal-horn sensitization or disinhibition can allow normally innocuous Aβ touch signals to be experienced as pain.
• Clinical sensory testing and imaging show altered central pain processing. Weaker conditioned pain modulation—an index of descending inhibitory control—correlates with greater clinical pain in PHN.
• Ongoing peripheral nociceptor hyperexcitability and ectopic discharges from injured axons, demyelinated segments, or dorsal-root-ganglion neurons are biologically credible contributors and may help drive central changes. However, spontaneous peripheral activity has not been directly recorded in people with persistent PHN, and this mechanism is unlikely to apply uniformly.

Bottom line

• The claim is substantially supported: herpes zoster injures and inflames sensory neural structures, and PHN persists after rash resolution with well-supported central sensitization plus a plausible, variable contribution from ongoing abnormal peripheral nerve activity.