Post-herpetic neuralgia

Also called PHN, Nerve pain after shingles

Pain that outlasts the shingles rash, sometimes for years. The vaccine prevents it, and early antiviral treatment reduces it.

What it is

Nerve pain persisting for more than three months after a shingles rash has healed.

It is the commonest complication of shingles and its likelihood rises sharply with age: uncommon under 50, and affecting a substantial minority of people over 70. It can last months or years, and in some people it is permanent.

The pain is neuropathic, meaning it comes from damaged nerves rather than damaged tissue, and it therefore does not respond well to ordinary painkillers. That is the single most important practical point: paracetamol and anti-inflammatories rarely help, and the treatments that do are drugs usually thought of as antidepressants or anti-epileptics, which needs explaining or people assume they are being fobbed off.

Two things reduce the risk. Antiviral treatment started within 72 hours of the rash appearing reduces the chance of persistent pain. And the shingles vaccine, offered on the NHS to older adults and to some immunosuppressed people, prevents both shingles and post-herpetic neuralgia. Uptake is well below where it could be.

Shingles affecting the eye can cause both sight loss and severe persistent pain, and needs same-day assessment.

Signs you might notice

Burning, stabbing or aching pain in the area where the rash was, usually a band on one side of the body or face.

Extreme sensitivity, so that clothing, bedding, water or a breeze causes severe pain.

Itching, numbness, or a crawling sensation in the same area.

Pain that disturbs sleep and does not respond to ordinary painkillers.

Depression, weight loss and social withdrawal, which are common and frequently unrecognised consequences.

Urgent, during shingles: rash near the eye, eye pain or redness, or any change in vision; rash affecting the ear with facial weakness; and shingles in anyone immunosuppressed.

At any time: pain that is unmanageable, or new weakness.

How it can affect day-to-day life

It is a genuinely disabling condition in older people and it is consistently under-treated, partly because pain in old age gets normalised.

The sensitivity is what people find hardest to convey. Not being able to bear a shirt or a bedsheet on one side of the body affects sleep, dressing and personal care.

For someone with dementia or limited communication, this pain shows up as distress, agitation or resistance to care, and is treated as behaviour. A history of shingles months earlier is the clue.

Neuropathic pain drugs are started low and increased slowly, and take weeks to work. People stop them in the first fortnight concluding they do nothing, which is the commonest reason treatment appears to fail.

Depression and pain reinforce each other here more than most conditions, and treating both works better than treating either.

Supporting someone well

Get the shingles vaccine when offered. It is the only true prevention.

During shingles, start antiviral treatment within 72 hours. Go to a GP or pharmacist on day one, not day four.

Expect neuropathic pain medication rather than ordinary painkillers, and explain why so it is taken properly.

Start low, go slow, and give it several weeks before judging it.

Ask about topical treatments: lidocaine plasters and capsaicin can help, particularly where touch is the trigger.

Protect the area: loose, soft clothing, and a bed cradle to keep sheets off the skin.

Ask for a pain clinic referral if it is not controlled after a few months.

In someone who cannot report pain, consider it when distress follows a shingles episode months earlier.

Treat the mood and the sleep as part of the pain.

Where to get help

A GP practice for treatment and for referral to a pain service.

A pharmacist on day one of a shingles rash; antivirals are time-critical.

Same-day eye assessment for shingles near the eye.

British Pain Society list specialist pain services, and the pain charities publish neuropathic self-management material.