Postherpetic neuralgia: pain after shingles

Shingles happens when the chickenpox virus, which has lain quietly in nerve cells since childhood, becomes active again. It produces a painful one-sided rash in the area served by a single nerve. For most people the pain eases as the blisters heal.

In some, the nerve itself has been injured by the infection and keeps sending pain signals. That lasting pain is postherpetic neuralgia. The NHS explains that it is caused by damage to your nerves from shingles, and that it is not known why some people carry on having pain for a long time after the rash has gone.

The word neuralgia simply means pain along a nerve. Pain of this kind is called neuropathic, which helps explain why it responds differently to treatment than the pain of a sprain or a headache.

Symptoms are found in the same patch of skin where the rash was, often a band around one side of the chest or tummy, but sometimes the face or head. The NHS says they usually begin during the rash or soon after it clears. In rare cases they start a few weeks or months later.

• Aching, burning or sharp pain that may be constant or may come and go.

• Skin that is extremely sensitive, so that light touch, pressure or a change in temperature hurts.

• Itchy skin.

• Loss of feeling in the area.

The NHS notes the pain is often mild, but some people have severe pain. Where it is severe, the effects can spread well beyond the skin. Sleep is often disturbed because even the weight of a duvet can hurt. Eating, concentration and mood can all suffer when pain persists.

People sometimes avoid dressing, bathing or going out because of the fear of being touched. Tell the GP if pain is affecting daily activities. The NHS says that when pain is severe, interferes with daily life, or has not responded to GP-prescribed medicines, referral for further help can be considered.

The NHS says post-herpetic neuralgia is more likely when shingles symptoms were severe and when the rash covered a large area of the body. It is also more common in older people and in people with other health conditions such as diabetes or a weakened immune system.

Shingles that affects the eye or face needs particular attention. The NHS lists a rash on the eye or nose, changes to vision, pregnancy and a severely weakened immune system among the reasons to ask for an urgent GP appointment or help from NHS 111 rather than waiting.

Having had shingles once does not rule out a second episode, and each episode carries its own chance of lasting pain.

The NHS says that getting treatment for shingles as soon as possible can help recovery and reduce the risk of post-herpetic neuralgia. Antiviral tablets may be offered if you have a weakened immune system, if pain or rash is moderate or severe, or if the rash affects areas other than the chest, tummy and back. The NHS says treatment usually needs to start within 3 days of the rash first appearing, and a pharmacist can supply the same antivirals as a GP for adults.

The shingles vaccine reduces the risk of shingles and of post-herpetic neuralgia. NHS eligibility is based on age and immune status and changes over time, so the NHS page on the vaccine, or the GP surgery, is the place to check current rules. Even someone who has had shingles can be vaccinated, because it can happen more than once.

There is no blood test or scan that confirms the condition. Doctors recognise it from the story: shingles in the past and pain that has not settled in the area of the rash. The NHS advises seeing a GP if you have had shingles and the pain does not get better where you had the rash.

A GP will usually examine the skin and check how touch, temperature and pinprick are felt. Other causes of pain, such as muscle strain, gallbladder disease or heart problems for chest-wall pain, are considered if the picture is unclear.

The NHS says the condition can be difficult to treat. A GP will usually start with paracetamol, or paracetamol with codeine, for mild to moderate pain, though this is unlikely to relieve pain completely. If it is not enough, medicines made for nerve pain such as amitriptyline, duloxetine, gabapentin or pregabalin may be prescribed. They do not work straight away: you usually begin on a low dose that is increased gradually over several weeks, with check-ups for benefit and side effects.

Lidocaine plasters can be used for mild pain, or when other medicines are unsuitable. Tramadol may be prescribed for severe pain, usually only for a short time. Anyone taking these should follow the prescriber's directions and ask a pharmacist about side effects such as drowsiness.

When medicines fail, the GP may refer to a specialist pain clinic or a neurologist. Options there can include stronger skin patches, injections or talking therapies, including cognitive behavioural therapy to help with coping.

• Wear loose cotton or silk clothes to avoid irritating the skin.

• Protect very sensitive skin with a layer of bandage, cling film or a plastic wound dressing under clothing.

• Hold an ice pack wrapped in a tea towel on the painful area for up to 20 minutes every 2 to 3 hours.

• Take cool baths or showers.

• Keep a daily pain diary to see whether treatment is working.

The pain usually improves with time, even though recovery can range from a few months to more than a year. For many people it eventually fades to the point where medicine can be reduced under medical supervision. Never stop nerve-pain tablets suddenly without advice.

On the NHS the path begins with the GP, who can try medicines and, if needed, refer on to a pain clinic. People who choose to see a private pain specialist can ask about the same range of options and should share the results with their GP. Specialist services differ in what they offer, so it is sensible to ask what treatments are available and how success is measured.

Seek urgent help for a shingles rash near the eye, new weakness in the face, or a high temperature with severe headache.