What Is Shingles (Herpes Zoster Virus)?

Why It Happens and How to Prevent It

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Herpes zoster, also known as shingles, is a viral disease characterized by the outbreak of painful, blistering rash that occurs when a latent chickenpox infection suddenly reactivates.

Chickenpox is caused by the varicella virus (VZV) that belongs to the same family of viruses that causes genital and oral herpes. After a chickenpox infection, the virus will go into a period of latency where it lies dormant in certain nerves of the body. In later life, the virus can spontaneously reactivate and cause the painful, blistering disease we recognize as shingles.

There are over one million cases of shingles in the United States every year.

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Shingles (herpes zoster) on man's chest (https://commons.wikimedia.org/wiki/File:Herpes_zoster_chest.png)

Fisle / Wikimedia Commons

Types

When a person gets chickenpox, the immune system will eliminate VZV from most locations of the body, but it will remain dormant within a cluster of nerve cells called a spinal ganglion. Some people refer to this as the spinal nerve root. When reactivation occurs, the outbreak will develop on an area of skin, called a dermatome, serviced by that specific spinal nerve.

There are a total of 30 spinal nerve roots with a corresponding dermatome on either side of the body. These are broadly categorized as:

  • Cervical nerves, serving the head, neck, shoulders, collarbone, upper back, arms, hands, and fingers
  • Thoracic nerves, serving the upper chest, back, upper forearm, upper abdomen, and lower abdomen
  • Lumbar nerves, servicing the lower back, buttocks, hips, inner thighs, knees, lower legs, and tops of the feet
  • Sacral nerves, servicing the lower back, back of the legs, buttocks, genitals, heels, and outer toes
  • Coccygeal nerves, servicing the area around the coccyx (tailbone)

In addition to the cutaneous (skin) herpes zoster, shingles can also cause:

Symptoms

Herpes zoster causes the formation of a painful blistering rash. The rash usually appears on one area of the skin on one side of the body (i.e., unilaterally).

Symptoms of shingles tend to progress as follows:

  • The initial onset pain, burning, numbness, tingling, or sensitivity on a specific part of the body
  • The appearance of red rash a few days after the pain
  • The development of fluid-filled blisters that rupture and crust over

The appearance of a shingles rash is frequently accompanied by itchiness, fever, headache, fatigue, and sensitivity to light. Less commonly, shingles pain can develop without any rash.

Most cases of shingles last for 3 to 5 five weeks.

Complications

For some people, shingles pain can persist for many months and even years. This type of pain is known as postherpetic neuralgia. It is a chronic condition that can significantly affect a person's quality of life.

People who develop herpes zoster ophthalmicus commonly experience eye redness, eye pain, and light sensitivity, and, in severe cases, vision loss.

Those with herpes zoster oticus may experience facial palsy, tinnitus (ringing in the ears), vertigo, and hearing loss.

People who are severely immunocompromised, such as those with advanced HIV, may experience disseminated shingles that extends beyond the affected dermatome to adjacent skin and organs (like the brain and liver). When this occurs, shingles can be potentially lethal.

Causes

Although scientists know that shingles is caused by the reactivation of VZV, they are less clear as to why the virus reactivates and what factors bring the virus out of a prolonged period of latency.

Diminished immunity is largely believed to be the cause. People with an intact (normally functioning) immune system can usually keep the virus in check. If the immune system is suppressed, the virus is more likely to reactivate and cause an outbreak.

This may largely explain why people over 50, who often have less robust immune systems than younger people, account for half of all shingles cases in the United States.

The risk of herpes zoster increases with age. By age 85, roughly 50% of people will have had at least one shingles outbreak in their lifetime.

Even so, younger adults and even children are known to experience shingles. While the cause is often related to immunosuppression or immunosuppressive therapies, some outbreaks appear entirely idiopathic (without any known cause).

Diagnosis

Shingles can often be diagnosed by symptoms alone given the characteristic pattern and appearance of the blistering rash.

With that said, certain forms of herpes simplex (known as zosteriform herpes simplex) can mimic shingles and be differentiated with a blood test called an IgM antibody test or a skin test called a Tzanck smear. If needed, a scraping of tissue can be sent to the lab for identification using polymerase chain reaction (PCR) which amplifies viral DNA.

If in doubt, the doctor may explore other possible causes in their differential diagnosis, including:

Treatment

There is no cure for shingles, but the early use of antiviral drugs—ideally within the first 72 hours of the appearance of symptoms—may be able to reduce the severity and duration of symptoms. There is even evidence, albeit weak, that it may help reduce the risk of postherpetic neuralgia.

The antivirals commonly use to treat shingles include:

  • Famvir (famciclovir)
  • Valtrex (valacyclovir)
  • Zovirax (acyclovir)

After 72 hours, the benefits of antiviral therapy tend to drop significantly.

Pain can be controlled with over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs), topical numbing agents (like lidocaine or capsaicin), or prescription medications like Elavil (amitriptyline) and Neurontin (gabapentin).

Prevention

Shingles can be prevented with a vaccine called Shingrix. Approved for use in 2017, the shingles vaccine is delivered by injection into the upper arm in two doses separated by 2 to 6 months.

Shingrix is recommended for all adults 50 and older even if they have received the previous shingles vaccine (called Zostavax) or had shingles in the past.

Side effects include injection site pain, redness, and swelling as well as fatigue, headache, body aches, and nausea. Most side effects are relatively mild and tend to resolve within a day or two.

According to the Centers for Disease Control and Prevention (CDC), two doses of Shingrix are 90% effective in preventing shingles.

Coping

Some people find it difficult to cope with the pain of a shingle outbreak. Even the rubbing of clothes against the blistering rash can cause extreme pain, making it difficult to concentrate, sleep, or carry on with daily activities.

Here are some tips that can help you deal with the aggravation and discomfort of shingles:

  • Apply a cool washcloth to blister to ease the pain.
  • Ice application can also help, limiting treatment to 15 to 20 minutes several times a day.
  • Wear loose, breathable fabrics.
  • Take a cooling oatmeal bath to help reduce inflammation.
  • Gently apply calamine lotion to affected tissues.
  • Take your mind off the discomfort by listening to music, watching TV, reading, taking a walk, or practicing mind-body therapies.

A Word From Verywell

If you or a loved one get shingles, it is important to respond quickly so that antiviral therapy can be prescribed. If your doctor is not available, do not hesitate to access telehealth services. Most telehealth providers can authorize and prescribe treatment based on the appearance of the outbreak and a quick review of your medical history.

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