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Updated 13 February 2013

Shingles (herpes zoster)

Shingles is a painful rash caused by the reactivation of the chickenpox virus.

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Summary

  • Shingles is a painful rash caused by the reactivation of the chickenpox virus.
  • Shingles appears as a strip of small blisters on a reddened skin, usually on one side of the trunk or face.
  • One of the most common complications is post-herpetic neuralgia: a deep pain that can last for months, even years, after the rash has cleared.
  • There is no known cure – shingles usually passes within a few weeks – but certain types of treatment can minimise the duration, discomfort and complications.
  • To be effective, treatment must be sought within the first three days of the appearance of the shingles rash.
  • If shingles appears on the face, particularly close to the inner corner of the eye, care must be taken against eye damage. Examination by an ophthalmologist is advised.
  • Shingles is most prevalent in people over 70, and almost exclusive to people over the age of 50.

Description

Shingles is sometimes called herpes "zoster", a Greek word meaning "girdle" or "belt", which describes the appearance of the rash. The Afrikaans name, "gordelroos", is also descriptive of the appearance.

The first sign is a sensation varying from a tingling feeling to a severe pain or a burning sensation on the skin, limited to the body area where the rash will appear. This can be anywhere, but it mostly occurs somewhere on the trunk (chest, abdomen, back).

Then, as the rash develops, the skin reddens in a horizontal strip resembling a "girdle"; however, unlike a girdle, the band does not encircle the body, but ends at the midsection. This means shingles usually appears on the one side of the body only. Very rarely does it appear on more than one place.

Small blisters, resembling chickenpox, appear on the "girdle". Eventually they fill with clear fluid, break and crust, before finally disappearing.

Pain and skin sensitivity accompanying the rash can be severe, and it can last for months – and sometimes years – after the rash has cleared. This is known as post-herpetic neuralgia.

On occasion no rash appears, and the patient only experiences the pain.

Cause

The culprit is a germ called the varicella zoster virus (VZV), the chickenpox virus. When it first enters the body, as it does in the case of 90% of all children, it leads to chickenpox. But the body is never totally rid of VZV, which belongs to a family of viruses known as the “herpes viruses” that become latent in their host after causing the first infection. Herpes viruses manage to hide in certain types of nerve cells near the spine and brain. There they lie dormant, literally for decades, because chickenpox is a childhood disease and shingles occurs mostly among people over 50. When the virus is reactivated it will cause shingles, not chickenpox.

Why the virus reawakens after so many years is very often not known exactly. In clearer-cut cases the virus reappears in people with leukaemia, Aids and chemotherapy patients because of the weakening of their immune systems. But generally shingles is ascribed to the weakening of the immune system that accompanies old age and poor diet. It has also been linked to stress, emotional trauma, and injuries to the spinal cord, or it may follow a serious illness.

The human skin is "wired" with nerves that run like branches from the spinal cord. Each of these branches serve a horizontal strip of skin on one side of the body. The virus reawakens in one of these branches, which explains the limited extent and strip-like pattern of the eventual rash: the rash will appear only on the patch of skin served by the nerve in which the virus has become reactivated.

The virus very seldom becomes reactivated in more than one nerve at a time. Only in severe cases of weakened immune systems will the rash spread to other areas of the skin, sometimes across the midline like a real girdle or even to internal organs like the liver and lungs.

It is the activity of the virus in the nerve that causes the pain associated with shingles. Not only has the virus used the nerve cells as its home for years, but as soon as it reawakens, it starts using the nerve as a highway to travel towards the skin. This causes the pain and irritation felt even before the rash appears. When it reaches the skin, the blisters form, and the virus life cycle runs its course with new infectious virus being shed from the blisters to susceptible individuals coming into contact with the shingles rash. But often it has a very unpleasant after-effect, known as post-herpetic neuralgia.

The deep pain associated with post-herpetic neuralgia is caused by damage to the nerve during the shingles attack. In these cases, the nerve can no longer send the correct signals to the brain. Signals are amplified and confused, causing the sensation of pain, even though there is no longer injury to the skin.

Symptoms

  • Shingles often starts with a general feeling of discomfort, itchiness and a slight fever.
  • The patient usually experiences pain, which can be very intense, on one side of the body. It is sometimes felt in the chest, so that the patient, and even the health professional, could mistake it for a heart attack.
  • A patch of skin on one side of the body becomes increasingly painful, sensitive and tender. Itching, numbness, tingly sensations and severe pain can be experienced.
  • Within two to three days after the first pains a rash appears in a horizontal "belt" of reddened, inflamed skin. Small blisters appear, resembling chickenpox.
  • The rash lasts for 10 to 14 days before the blisters, which have filled with clear fluid, crack and start to heal. The forming of blisters has been known to continue for up to a month and shedding of varicella virus occurs in the blister fluid.
  • Pain that continues after the rash has cleared is symptomatic of post-herpetic neuralgia. It varies in intensity and type. Sometimes it is experienced as a deep continuous burning or aching, sometimes as intermittent stabbing pains. In some extreme cases, the pain is so intense that it can lead to depression and suicidal thoughts.
  • In rare cases of post-herpetic neuralgia, damage to the nerves during shingles can also lead to loss of muscle control in the affected area.
  • Although post-herpetic neuralgia in most cases only lasts for up to four months, in two to three percent of cases it lasts for more than a year. In rare cases, sufferers live with the pain for the rest of their lives. The older the patient, the worse and the longer lasting the pain tends to be.

Prevalence

Shingles occurs most commonly in people above the age of 50, and then mostly in people over 70. According to American statistics, one in ten to one in five people over the age of 50 will suffer an outbreak of shingles once during their lifetime. Very rarely does an individual get shingles twice.

About half of all shingles patients experience post-herpetic neuralgia. The likelihood of this condition increases with age. Post-herpetic neuralgia occurs in at least half of shingles patients over 60 and three-quarters of those over the age of 70.

Risk factors

  • People over the age of 50 who have had chickenpox are at risk of getting shingles.
  • A weakening of the immune system can precipitate an outbreak of shingles. This can be through serious illness, stress, or trauma.

When to see a doctor

There is no known cure for shingles, but treatment soon after the outbreak can shorten the duration and minimise the complications. A health care professional should be called when any of the following symptoms are experienced:

  • Severe pain on one side of the body.
  • A sensitive, tender patch of skin on one side of the body.
  • Small blisters on the skin, resembling chickenpox.
  • An outbreak of shingles that involves your forehead and nose – make sure you are examined by an ophthalmologist to prevent eye damage.
  • Inflammation of the rash and the appearance of red streaks – it could mean that you have contracted a secondary bacterial infection, which requires treatment with antibiotics.

Diagnosis

The doctor will look for the signs of shingles as listed under "symptoms". Usually the diagnosis is made on the grounds of the tell-tale band-like rash.

Sometimes, however, the infection can manifest in a way that causes some initial confusion. The pains that go along with shingles can be intense and can even be mistaken for a heart attack or backache.

Sometimes the rash never appears, and the patient only suffers pain. In such uncertain cases tests can be done to establish the presence of the chickenpox virus.

The following tests are available to help confirm a diagnosis of shingles:

  • A Tzanck smear of the fluids in the blisters.
  • A skin biopsy.
  • A blood test.

Treatment

There is no known cure for shingles. The virus runs its course and usually disappears after two to three weeks. However, evidence suggests that certain treatments in the first three days after appearance of the virus can significantly reduce the duration and complications involved.

Home treatment
The following can be tried while the rash is active:

  • Wear light clothing over the infected skin or keep it open.
  • The area can be washed with soap and water.
  • The rash can be bandaged at night to avoid touch irritation.
  • The application of ice often helps to relieve symptoms.
  • Pain can be relieved by applying a mixture of crushed aspirin and rubbing alcohol to the rash.
  • The blisters should not be broken or scratched.
  • For post-herpetic neuralgia, the pain that lingers after the rash has cleared, try the following:
  • Capsaicin, an over-the-counter cream containing certain extracts from chilli peppers: when applied to the skin surface, it temporarily removes certain chemicals from the nerve endings and prevents nerves from sending pain messages to the brain. The cream has to be applied regularly. At first it might produce a burning sensation. Unfortunately, this treatment is not yet available in South Africa.
  • Desensitisation of the affected skin patch: if the skin tends to be very sensitive to cold, for example, the application of ice may desensitise the area. Or if touching causes pain, a hard rubbing can lessen the sensitivity.
  • Transcutaneous electrical nerve stimulation (TENS): this device sends small electrical impulses through electrodes into the affected area. The TENS unit can be switched on or off depending on the level of pain experienced.

Medication
Although there is no cure, there is evidence to suggest that treatment with antiviral and anti-inflammatory drugs can shorten the duration of the rash and reduce the severity of post-herpetic neuralgia. Early treatment with antiviral medication such as Famvir or Zelitrex may shorten the course of the disease and diminish the severity and risk of post-herpetic neuralgia. Treatment must however be started within three days of the outbreak.

Medication in the treatment of shingles is mostly for the relief of pain for the duration of the rash and the subsequent post-herpetic neuralgia. These include:

  • Antidepressants: tricyclic antidepressants, like amitriptyline, are often given to sufferers of post-herpetic neuralgia, but in smaller dosages than for sufferers of depression. The success of these drugs for pain relief differ from patient to patient. It is often very successful.
  • Anticonvulsive drugs: drugs developed against conditions like epilepsy have been found to be effective pain relievers. These drugs include phenytoin, carbamazepine and valproate.

Surgery
As a last resort, surgery is performed to relieve continuous and unbearable pain. The procedure involves cutting the damaged nerve from the spinal cord so that pain messages can no longer be transmitted to the brain. The procedure is risky and should be considered only as a very last resort.

Reviewed by Dr Eftyhia Vardas BSc (Hons), MBBCh, DTM&H, DPH, FC Path (Virol), MMed (Virol), Clinical Virologist, Director HIV/AIDS Vaccine Division, Perinatal HIV Research Unit, Chris Hani Baragwanath Hospital, University of the Witwatersrand and senior lecturer, Department of Infectious Diseases, Faculty of Health Sciences, University of the Witwatersrand.

 
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