Postherpetic Neuralgia (Pain After Shingles)

Key facts

What postherpetic neuralgia is

Shingles (herpes zoster) is a reactivation of the chickenpox virus, which lies dormant in nerve roots for decades. About 1 in 3 people will have shingles in their lifetime. When it reactivates, the virus travels down one sensory nerve to the skin, causing a painful blistering rash in a band on one side of the body, most often the chest or trunk (about half of cases), the face (10 to 20 percent, usually the forehead and eye region), or the neck and low back.

The rash heals in 2 to 4 weeks. In most people the pain fades with it. In some, the virus has damaged the nerve badly enough that pain continues long after the skin has healed. When pain lasts 90 days or more from the start of the rash, it is called postherpetic neuralgia. Roughly 10 to 18 percent of people with shingles develop PHN. Under age 50 it is uncommon; over 60 the risk climbs steeply, and among people over 70 with shingles more than a quarter develop it. Gulf Coast Pain & Spine treats PHN in Houston, Webster and Pearland (opening November 2026).

Why it happens and who is at risk

The virus inflames and destroys part of the sensory nerve and its cell bodies in the dorsal root ganglion next to the spine. The damaged nerve fires spontaneously and the spinal cord becomes sensitized to its input, so the skin in that band feels pain from nothing, or from light touch. Risk factors for developing PHN after shingles:

• Age over 60 (the strongest factor)
• Severe pain during the outbreak, or pain that began before the rash appeared
• A large or severe rash
• Shingles affecting the face (ophthalmic division of the trigeminal nerve)
• Antiviral treatment started late or not at all
• Weakened immunity, diabetes

Prevention: the recombinant shingles vaccine (two doses, recommended for adults 50 and older and for younger adults with weakened immunity) is about 90 percent effective at preventing shingles and PHN. If you have had shingles, you can still receive the vaccine once the rash has resolved to prevent a recurrence. Ask your primary care physician or pharmacist.

Symptoms, and how PHN differs from look-alikes

PHN stays inside the band of skin the rash occupied, on one side, and does not cross the midline. Typical features:

• Constant burning, aching or deep pain
• Sharp, stabbing or electric jolts on top of the constant pain
• Pain from light touch, clothing or a breeze (allodynia); many patients cannot wear a shirt or bra over the area
• Itching, numbness or altered sensation in the same band
• Faint scars or changed skin color where the blisters were

Chest-wall PHN can be mistaken for heart, lung or rib pain; the giveaway is the one-sided band that follows a rib and the history of a rash. PHN on the low back and buttock is sometimes labeled sciatica, but it lacks the leg-length radiation and the back-movement triggers. Rarely, shingles causes pain without a visible rash (zoster sine herpete), which is diagnosed by the pattern and, if needed, blood tests for the virus.

How we diagnose it

PHN is diagnosed from the history of shingles and an exam showing pain or altered sensation confined to the affected dermatome. We map the painful area, test for allodynia with a cotton swab and for numbness with pinprick, and photograph the area to track change. No imaging or nerve test is needed for a typical case. Tests are ordered only when something does not fit: pain crossing the midline, no history of rash, weakness in the limb, or a picture that could be a compressed nerve root or a chest or abdominal problem. If shingles involved the face, we confirm that an ophthalmologist has examined the eye.

Bring the date the rash started, whether and when you took an antiviral, and a list of every medication tried for the pain and at what dose. Most "failures" turn out to be doses that were never raised high enough.

Treatment options, in order

Timing changes the outcome. During the outbreak, antivirals (valacyclovir, famciclovir or acyclovir) started within 72 hours of the rash shorten the illness and reduce acute pain, and early aggressive pain control in the first weeks appears to lower the risk of long-term PHN. If you are still in the rash phase, your primary care physician or urgent care should start these today, and we can see you early for pain control and, in severe cases, a nerve block. Once PHN is established, the plan below applies. Several of the medications are FDA-approved specifically for PHN.

1. Topical first-line

   Lidocaine 5 percent patches (up to three patches, 12 hours on and 12 off) over the painful skin are FDA-approved for PHN, work within days, and have almost no systemic side effects. Capsaicin cream, or the prescription 8 percent capsaicin patch applied once in the office for 60 minutes with relief lasting up to 3 months, is the other approved topical.

2. Oral first-line medication

   Gabapentin (FDA-approved for PHN; titrated to 1,800 to 3,600 mg per day in divided doses) or pregabalin (FDA-approved; 150 to 600 mg per day). Low-dose tricyclics (nortriptyline or amitriptyline at bedtime) are effective and help sleep but are used cautiously over age 65 or with heart disease. Duloxetine is an alternative. Each needs 4 to 8 weeks at a working dose. Learn more →

3. Nerve blocks

   For chest or abdominal wall PHN, an intercostal nerve block (local anesthetic with or without steroid injected under the rib next to the affected nerve) can break the pain cycle and is repeated if it helps. Paravertebral or epidural steroid injections at the affected level are used for trunk PHN, especially early. For facial PHN, a stellate ganglion block or trigeminal branch block is considered. These are treatments; response varies, and relief typically lasts weeks to a few months. Learn more →

4. Combination and second-line

   Combining a topical with a gabapentinoid or tricyclic gives more relief than either alone. Tramadol or short opioid courses have some evidence in PHN but carry real risks in older adults; they are not first-line and any controlled-substance decision is made by the physician after evaluation and records review.

5. Peripheral nerve stimulation

   For PHN that remains disabling after medications and blocks, a temporary peripheral nerve stimulation lead placed near the affected intercostal or other nerve, or spinal cord stimulation, is considered. Evidence for PHN is from smaller studies rather than large trials, and insurers review coverage individually. A trial period comes first. Learn more →

What you can do now

• If the rash is new, get antivirals today. The 72-hour window matters.
• Protect the skin from touch. Loose cotton clothing, a dressing over the area, or a lidocaine patch under clothing reduces allodynia flares.
• Cool, not hot. Cool packs wrapped in a towel ease burning for many patients; heat often makes it worse.
• Take medications on a schedule, not as needed; nerve pain drugs work by keeping a steady level.
• Keep moving and keep sleeping. Isolation and poor sleep make PHN louder; ask us early for a sleep plan.
• Get vaccinated once recovered to prevent a second episode.

New patients can start at new patient information; physicians can use the referral page.

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