When pain persists after the lesions disappear

Herpes zoster is a reactivation of latent varicella-zoster virus in sensory ganglia, causing a painful vesicular eruption along a dermatome. In most patients, the vesicles heal in 2–4 weeks. However, in a significant share — especially over age 60 — pain persists for months or years after the resolution of skin lesions. This condition is postherpetic neuralgia (PHN), one of the most debilitating forms of chronic neuropathic pain.

PHN manifests as continuous burning, hypersensitivity to light touch (allodynia), and stabbing lancinating pain in the region of the previously affected dermatome. The impact on quality of life is devastating: it interferes with sleep, daily activities, and mood. Electroacupuncture, particularly the technique of "surrounding needling" around the affected dermatome, has demonstrated efficacy in modulating peripheral and central sensitization that maintains neuropathic pain.

Mechanism of neuropathic pain and action of acupuncture

  1. Sensory nerve injury by the virus

    Varicella-zoster virus causes necrosis and inflammation of nerve fibers in the dorsal ganglion and along the peripheral nerve. C fibers (slow pain/burning) and A-delta fibers (sharp pain/stabbing) are damaged, generating spontaneous ectopic signals — aberrant electrical discharges that the brain interprets as continuous pain.

  2. Peripheral sensitization

    The surviving nociceptors in the skin of the affected dermatome become hyperexcitable (peripheral sensitization). Normally painless stimuli — such as the touch of clothing on the skin — begin to be perceived as intense pain (mechanical allodynia). This alteration can persist for months after vesicle healing.

  3. Central sensitization in the spinal cord and brain

    Prolonged ectopic activity of peripheral nerve fibers induces central sensitization: neurons of the dorsal horn of the spinal cord and thalamus amplify pain signals, even when peripheral stimulus is minimal. This central sensitization is the main mechanism of PHN chronicity.

  4. Surrounding needling and electroacupuncture 2 Hz

    The "surrounding needling" technique (围刺, wéi cì) consists of inserting needles around the área of maximum pain. Combined with electroacupuncture at 2 Hz, it promotes release of enkephalins and beta-endorphins, modulates central sensitization via the descending inhibitory pain system, and improves local microcirculation in the affected dermatome.

  5. Modulation of the local immune system

    Acupuncture in the affected dermatome promotes release of adenosine and local anti-inflammatory peptides, reducing residual neuroinflammation that contributes to maintenance of peripheral sensitization. This action complements the central neuromodulatory effect.

Epidemiology of postherpetic neuralgia

Significant minority
OF PATIENTS WITH HERPES ZOSTER
develop PHN — with risk increasing substantially with age, being particularly elevated in patients over 60–70 years
Marked reduction
WITH VACCINATION (SHINGRIX)
the recombinant vaccine against herpes zoster substantially reduces the incidence of the disease and of PHN in adults over 50 years in phase III clinical trials — reinforcing the importance of prevention
3–6
MONTHS AVERAGE DURATION
is the typical duration described for PHN in treated patients, with a relevant minority persisting with pain for more than a year — justifying an early and multimodal approach
Improvement described
IN SYSTEMATIC REVIEWS
reviews of acupuncture for PHN describe reduction of pain scores (VAS) and improvement in quality of life in some patients — methodologic quality and heterogeneity between studies still limit definitive conclusions

Recognizing postherpetic neuralgia

Critérios clínicos
07 itens

Postherpetic neuralgia \u2014 clinical pattern

  1. 01

    Continuous burning in the área of the dermatome previously affected by herpes zoster

  2. 02

    Allodynia — intense pain with light touch of clothing or sheet on the skin

  3. 03

    Spontaneous electrical or lancinating stabbing pain in the region

  4. 04

    Neuropathic pruritus (deep, intense itching without dermatologic cause)

  5. 05

    Scars or pigmentation alteration in the dermatome (marks of prior herpes)

  6. 06

    Nighttime worsening of pain with severe impact on sleep quality

  7. 07

    Hypersensitivity to cold or heat in the affected region

Myths and facts about post-herpes zoster pain

Myth vs. Fact

MYTH

If the skin lesions have healed, the disease is over

FACT

Vesicles are only the cutaneous manifestation of viral reactivation. The underlying neurologic damage — necrosis of nerve fibers, peripheral and central sensitization — can persist for months or years after complete skin healing. PHN is a disease of the nervous system, not the skin. Neuromodulatory treatment with electroacupuncture addresses this neurologic dimension.

MYTH

Common analgesics control PHN pain

FACT

PHN is neuropathic pain — it responds poorly to common analgesics and anti-inflammatories. First-line pharmacologic treatment per guidelines includes gabapentinoids (gabapentin, pregabalin) and dual antidepressants (duloxetine, amitriptyline), prescribed by the attending physician. Medical acupuncture is investigated as complementary treatment — it can contribute to pain relief and, in some patients, allow medication dose adjustment always under medical supervision.

MYTH

There is no possible prevention for PHN

FACT

The recombinant vaccine against herpes zoster (Shingrix) reduces the incidence of herpes zoster by more than 90% and of PHN by about 89% in adults over 50 years. Early initiation of antiviral (within the first 72 hours of herpes zoster) also significantly reduces the risk of PHN. Prevention is more effective than treatment of established PHN.

The therapeutic window of opportunity

Treatment protocol

Assessment and stratification
1st visit

Confirmation of PHN diagnosis. Measurement of pain intensity (VAS), mapping of the área of allodynia and hyperalgesia. Verification of antiviral use in the acute phase and current medications. Screening of risk factors for prolonged PHN: advanced age, intense acute pain, extensive rash.

Surrounding needling with electroacupuncture
Sessions 1–4

Surrounding needling technique: 6–8 needles inserted around the área of maximum pain, directed toward the center of the lesion. Electroacupuncture at 2 Hz between needle pairs for 30 minutes. Distal points LI-4, LR-3, and ST-36 to activate the descending inhibitory pain system. Sessions twice a week.

Consolidation and reduction of allodynia
Sessions 5–8

Addition of needling in the adjacent dermatome when there is radiation. Treatment of secondary myofascial trigger points in the paravertebral muscles of the corresponding level. Assessment of response: clinically significant reduction of VAS is sought in this phase — magnitude varies according to duration and intensity of the condition.

Maintenance and spacing
Sessions 9–12

Progressive spacing of sessions (weekly → biweekly → monthly). Guidance on herpes zoster vaccination for prevention of recurrence. Management of expectations: chronic PHN may require continuous intermittent treatment for satisfactory control.

Clinical pearl: age and early initiation

Scientific evidence

Frequently asked questions

FREQUENTLY ASKED QUESTIONS · 04

Frequently Asked Questions

Yes, provided the vesicles are completely healed and there is no active skin lesion. The surrounding needling technique is inserted around the área of maximum pain, not necessarily over the scars. The medical acupuncturist evaluates skin integrity before each session and adapts the technique as needed.

Yes, and this combination is frequently the most effective approach. Medical acupuncture acts through complementary mechanisms to gabapentinoids and antidepressants, potentially enhancing pain relief and allowing gradual reduction of medication doses — always under supervision of the attending physician. There are no contraindications between acupuncture and first-line drugs for PHN.

Yes. The Shingrix vaccine is recommended even for those who have already had herpes zoster, as it reduces the risk of recurrence. Vaccination should be done after complete resolution of the acute episode. Adults over 50 years, especially the immunosuppressed, should discuss vaccination with their physician.

In cases of recent-onset PHN (less than 6 months), substantial symptomatic resolution — in some cases complete — is described with early multimodal treatment. In long-duration PHN, the realistic objective is significant pain reduction and functional improvement, more than complete elimination of the condition. The medical acupuncturist discusses realistic expectations with each patient, based on duration and intensity.