Shingles and postherpetic neuralgia: pain treatment

Shingles (herpes zoster) is the reactivation of the chickenpox virus, which stayed dormant in the nerves: it causes a painful rash on a band of skin on one side of the body. In most cases the pain goes away as the skin heals; when it persists for more than three months we call it postherpetic neuralgia, a neuropathic pain that does not respond to common painkillers. The first days are a key window: antivirals within 72 hours and good control of the acute pain. Once established, the neuralgia is difficult to treat, but there are specific medications and procedures that can reduce the pain and restore quality of life.

What shingles is — and what postherpetic neuralgia is

Shingles is the common name for herpes zoster. Anyone who has had chickenpox keeps the virus dormant in the nerve ganglia, and years or decades later — usually when the immune defenses drop, with age or for other reasons — the virus reactivates and travels along a nerve to the skin. The result is the typical picture: pain, burning or tingling in a band of skin on one side of the body (the chest is the most frequent site, but it can be the face, the neck or a limb), followed a few days later by a blistering rash in that same band.

In most patients, the pain accompanies the rash and fades along with it, within two to four weeks. The problem is when it doesn't fade. We speak of postherpetic neuralgia when the pain persists for more than three months after the rash. At that point it is no longer the infection that hurts: it is the nerve, damaged by the passage of the virus, transmitting pain signals it should not be transmitting.

I'm an anesthesiologist with postgraduate training in Pain Medicine and interventional pain management, and postherpetic neuralgia is one of the conditions where I see the cost of arriving late most clearly. The typical patient is an older person who had shingles months ago, whose skin has healed, and who has lived ever since with a constant burning in that same band of skin, or with an area that can't bear the brush of a shirt. Often they were told it would "go away on its own." Sometimes it does. But when it doesn't, every month without specific treatment is a month lost.

Why the pain can stay

Postherpetic neuralgia is a neuropathic pain: it doesn't come from tissue inflammation but from the nerve itself, which was injured and now fires abnormal signals. That is why it feels different from ordinary pain, with that characteristic texture:

• Persistent burning in the area where the rash was
• Electric shock–like jolts, spontaneous or triggered by movement
• Stabbing or pins-and-needles sensations
• Allodynia: pain from stimuli that shouldn't hurt — the brush of clothing, a caress, the wind

And that is why common anti-inflammatories (ibuprofen, diclofenac) help little or not at all: they act on tissue inflammation, and the problem here is something else. Pushing ever-higher doses only adds side effects — gastritis, kidney problems, high blood pressure — without touching the mechanism of the pain. If you want to understand this type of pain better, I devote a full article to it: Neuropathic pain: why common painkillers aren't enough →

Who is more at risk of persistent pain

Not everyone who gets shingles develops postherpetic neuralgia. Studies analyzing thousands of cases have identified factors that increase the risk of the pain becoming chronic:

• Age: the most consistent factor. The risk rises sharply from age 50 and keeps climbing with each decade.
• Severe pain in the acute phase: the more the shingles hurts, the higher the likelihood the pain will stay.
• An extensive or severe rash.
• Pain before the rash appears (the painful prodrome — those days of burning before the blisters show up).

This risk profile has a practical consequence: if you are over 50 and your shingles hurts badly, this is not an illness to ride out with paracetamol and patience. It is one to treat properly from day one.

The first days matter: early treatment

The acute phase of shingles has a concrete treatment window:

Antivirals within 72 hours

Herpes zoster management guidelines recommend starting an antiviral (acyclovir, valacyclovir or famciclovir) ideally within the first 72 hours after the rash appears, especially in people over 50. The antiviral reduces the intensity and duration of the acute episode. Let me be honest about a nuance: it has not been shown that the antiviral, on its own, prevents postherpetic neuralgia — for acyclovir, good-quality evidence indicates it does not, and for the other antivirals the evidence is insufficient. But it shortens and eases the acute illness, and that alone is reason not to delay it.

Serious control of the acute pain

Severe pain in the acute phase is one of the risk factors for the pain becoming chronic. That is why pain management during shingles is not a side note: analgesics are used on scheduled regimens and, when the pain has neuropathic features from the start, specific neuropathic pain medications are started early. In selected cases with severe pain that won't settle, an image-guided nerve block can add relief in the first weeks; the evidence shows that benefit is short-term and that a block in the acute phase has not been shown to prevent the neuralgia in the long run, so I offer it as a tool for relief, not as insurance against the pain becoming chronic.

Prevention: the vaccine

There is a herpes zoster vaccine with high demonstrated efficacy in adults over 50. Preventing shingles is the most direct way to prevent postherpetic neuralgia. If you are over 50, discuss that option with your primary care doctor.

Treating established postherpetic neuralgia

Here is the part I owe it to you to say plainly: established postherpetic neuralgia is one of the most difficult neuropathic pains to treat. Even with first-line medications, only a portion of patients achieve substantial relief, and often the realistic goal is to bring the pain down to a level compatible with sleeping, moving and living a normal life, rather than eliminating it completely. That said, the difference between well-conducted specific treatment and simply "putting up with it" is usually enormous.

Specific drug treatment

International recommendations for neuropathic pain place three groups of medications in the first line — and there is a fourth resource with a special place in localized postherpetic neuralgia:

• Gabapentinoids (gabapentin, pregabalin): they act on calcium channels, modulating the signal from the sensitized nerve.
• SNRI antidepressants (duloxetine, venlafaxine): they reinforce the descending pathways that modulate pain — at doses and schedules designed for pain, not for an "antidepressant" effect.
• Low-dose tricyclic antidepressants (amitriptyline, nortriptyline): effective, though in older adults they call for extra caution because of their side effects.
• 5% lidocaine patch: applied over the painful area. Guidelines place it as second line, but in localized postherpetic neuralgia it has a special place because of its excellent safety profile: almost none of it is absorbed.

The rule I follow: start low, increase gradually as tolerated, allow at least four weeks at a stable dose before judging effectiveness, and combine two drugs with different mechanisms rather than pushing a single one to high doses. These medications ask for patience: the full effect takes 2 to 6 weeks to build, and stopping them too early is one of the most frequent mistakes.

When to add procedures

When well-conducted drug treatment isn't enough, image-guided procedures can be added:

• Selective nerve blocks over the affected territory — intercostal blocks when the neuralgia is thoracic, or others depending on the area — which can provide a window of relief.
• Pulsed radiofrequency: unlike conventional radiofrequency ablation — which is contraindicated on a damaged sensory nerve because it can make the pain worse — the pulsed mode produces no thermal lesion: it modulates the nerve's activity. It is used in selected neuropathic conditions, as a complement to drug treatment.

One clear limit, so as not to oversell: these procedures treat the pain — they do not repair the nerve. They are one tool within a comprehensive plan, not a replacement for medical management. And I don't offer unproven therapies for this condition: serious treatment of postherpetic neuralgia is what I have just described.

My approach to postherpetic neuralgia is stepwise and honest. First, a specific medication plan carried patiently up to effective doses — that is where most of the result is decided. The lidocaine patch almost always comes in early when the pain is localized, because it adds benefit without risk. Nerve blocks and pulsed radiofrequency I reserve for cases where a well-conducted medical plan has fallen short, and when I offer them I explain exactly what they can and cannot deliver. What defines a good outcome is not always zero pain: it is sleeping through the night again, tolerating clothing, going out for a walk without thinking about the pain all day.

When to seek help

A specific pain evaluation makes sense if: the rash has healed and the pain continues — you don't need to wait out the formal three months before consulting; the acute-phase pain is severe and doesn't settle with what you were prescribed; or you are over 50 and want the acute illness treated as well as possible from the start. In the acute phase, the 72-hour antiviral window makes time count; and if the skin has healed and the pain continues, there is no reason to keep living with that pain without specific treatment.

Where I see patients — locations in Buenos Aires

I see patients at two locations: Hepta, in San Isidro (Av. Fondo de la Legua 577, northern suburbs of Buenos Aires) and CIAREC, in Villa Urquiza (Av. Monroe 4770, Buenos Aires City). I receive patients from across the northern area of Greater Buenos Aires and from the city itself, and I also offer first consultations by telemedicine to orient you and organize next steps. Phone: +54 9 11 5895-3260.

Dr. Mauricio Casarsa

Anesthesiologist with postgraduate training in Pain Medicine and interventional pain management (UBA — Fundación Dolor; UNLP — CAIDBA). Staff physician at Hospital Alemán de Buenos Aires.

MN 137.756 (Argentine medical license) · San Isidro · Villa Urquiza