PONOS CLINIC · PAIN MEDICINE · TURIN
Trigeminal post-herpetic neuralgia
Facial pain after shingles: indications, timing and limitations of Gasserian and sphenopalatine ganglion PRF.
When to consider pulsed radiofrequencyConceptual illustration; not a diagnostic or anatomical image.
Acute shingles and post-herpetic neuralgia
Shingles results from reactivation of the varicella-zoster virus. Antiviral treatment should be assessed promptly, preferably within 72 hours of rash onset; later assessment remains important, especially with eye involvement. ICHD-3 defines trigeminal post-herpetic neuralgia as persistent or recurrent pain for at least three months in the affected territory. You do not need to wait three months to seek help.
Which areas of the face may be affected?
V1, the ophthalmic division, supplies the forehead and periocular region; possible eye involvement requires particular attention. V2 and V3 involve the cheek, upper jaw, lower jaw and related territories. The current pain distribution is compared with the original shingles episode.
Persistent symptoms and assessment
Burning, shooting pain, itching, reduced sensation and allodynia — pain from light touch — may continue after the skin heals. This condition must be distinguished from classical trigeminal neuralgia. Bring the onset date, photographs of the rash if available, eye reports, antiviral treatment details and medicines tried. Assessment considers sensory changes, sleep and daily activities.
Medicines and topical treatments
Options may include gabapentin, pregabalin or selected antidepressants, according to health conditions and tolerability. Topical products require particular caution on the face: do not apply patches or creams to eyes, mucous membranes or damaged skin. Site and preparation must be agreed with the treating clinician.
When is pulsed radiofrequency considered?
Interventional assessment may be appropriate when significant pain persists despite suitable, tolerated treatment, or adverse effects prevent its continuation. Allodynia, insomnia and restricted activities also matter. The diagnosis of shingles alone does not establish an indication: the painful territory, sensory examination, alternatives and individual risks must be reviewed.
Pulsed radiofrequency (PRF) aims at neuromodulation and differs from continuous thermal radiofrequency. Indications for destructive procedures used in classical trigeminal neuralgia cannot simply be transferred to post-herpetic pain, where the nerve is already injured.
Gasserian ganglion PRF
The Gasserian ganglion is the sensory ganglion of the trigeminal nerve. It is one of the targets studied for shingles-related trigeminal pain, alongside peripheral branches. Target selection depends on distribution and clinical findings; not every patient needs a ganglion procedure.
A 2019 randomised controlled trial in 96 patients with acute or subacute trigeminal shingles pain found benefits of Gasserian PRF compared with a sham procedure. Pain and quality-of-life outcomes improved, but this single-centre study does not guarantee individual benefit or prevention of chronic neuralgia.
For established trigeminal post-herpetic neuralgia, a 2022 trial compared PRF alone with PRF plus dexamethasone. It does not demonstrate superiority over all drug treatments.
Sphenopalatine ganglion PRF
The sphenopalatine ganglion (SPG) participates in craniofacial autonomic pathways. PRF at this target has been explored for ophthalmic shingles pain, but evidence is more limited than for Gasserian PRF.
A 2024 series of three cases described improvement in refractory ophthalmic shingles pain. Without a control group, it cannot establish a standard indication. A 2025 retrospective comparison involving 72 patients reported favourable results for combined SPG and trigeminal ganglion PRF compared with trigeminal PRF alone. Its non-randomised design prevents definitive conclusions about superiority.
SPG PRF may therefore be discussed in selected cases with clear explanation of the preliminary evidence. It is not automatically equivalent to Gasserian PRF, and V1 involvement alone is not an indication. Read about SPG pulsed radiofrequency.
Timing: when to seek assessment
- Acute shingles: prompt antiviral assessment and management of possible eye complications take priority. Severe or poorly controlled pain warrants early pain assessment.
- The following weeks: reassess treatment response. PRF studies include acute and subacute phases, but do not define one ideal day for everyone. The 72-hour window mainly concerns antivirals, not a deadline for RF.
- After at least three months: established trigeminal post-herpetic neuralgia can still be assessed for PRF if refractory. It is not automatically too late, but benefit and duration vary.
- Limits: there is no universal PRF window that guarantees prevention of chronic pain. Evidence does not establish specific SPG timing.
Safety and target selection
Facial and corneal sensation, existing deficits, anticoagulants, bleeding risk and infection are assessed before treatment. Do not stop medicines independently. Access-related risks, bleeding, infection and sensory changes are discussed; protection of the eye is especially important for V1. PRF does not replace antivirals or ophthalmic treatment.
How benefit is assessed
Pain intensity, tolerance of touch, sleep and daily activities guide follow-up. Relief may be partial and its duration variable; the plan is adjusted to the individual response.
Related trigeminal information
Trigeminal neuralgia · Diagnostic pathway · Trigeminal radiofrequency