Overview of Shingles (Herpes Zoster Virus)

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

Chickenpox is caused by the varicella virus (VZV), which 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. Later in life, the virus can spontaneously reactivate and cause the painful, blistering condition recognized as shingles.

This article discusses the symptoms, causes, and treatment of shingles, as well as how to prevent getting shingles.

Types of Shingles

There are over one million cases of shingles in the United States every year. About one in three people in the U.S. will have shingles during their lifetime.

When a person gets chickenpox, their immune system will eliminate VZV from most locations of the body. The virus will, however, remain dormant within a cluster of nerve cells called a spinal ganglion (also called a spinal nerve root).

When reactivation occurs, the outbreak will develop on a dermatome—an area of skin 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, serving the lower back, buttocks, hips, inner thighs, knees, lower legs, and tops of the feet
• Sacral nerves, serving the lower back, back of the legs, buttocks, genitals, heels, and outer toes
• Coccygeal nerves, serving the area around the coccyx (tailbone)

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

• Herpes zoster ophthalmicus, which moves from the trigeminal nerve to the ophthalmic nerve serving the forehand, eyelid, and eye
• Herpes zoster oticus, also called Ramsey Hunt syndrome, which moves from the facial nerve to the vestibulocochlear nerve of the ear

Shingles Symptoms

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

Symptoms of shingles tend to progress as follows:

• Initial onset of pain, burning, numbness, tingling, or sensitivity in a specific part of the body
• Appearance of a red rash a few days after the pain
• Development of fluid-filled blisters that rupture and crust over

The appearance of a shingles rash is frequently accompanied by:

• Itchiness
• Fever or chills
• Headache
• Fatigue
• Sensitivity to light
• Upset stomach

For some people, the symptoms of shingles are mild while others experience intense pain from a gentle touch or breeze.

Complications

Shingles usually clears in two to three weeks and rarely return, but sometimes complications can occur.

Postherpetic neuralgia (PHN): For some people, shingles pain can persist for many months and even years. It occurs when the nerves have been damaged after an outbreak of shingles. Pain ranges from mild to very severe and can significantly affect a person's quality of life. About 10% to 18% of people with shingles experience PHN, and the risk increases with age.

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

Herpes zoster oticus: People with this condition may experience facial palsy (weakness of facial muscles), ringing in the ears (tinnitus), vertigo, and hearing loss.

People who are severely immunocompromised, such as those with advanced HIV, and the elderly sometimes experience severe complications from shingles, such as:

• Pneumonia
• Hepatitis
• Encephalitis
• Meningitis 

Occasionally shingles can be fatal, but fortunately, these complications and death are rare.

Causes of Shingles

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 a 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.

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).

Is Shingles Contagious?

Someone with shingles cannot spread shingles to another person, but they can spread chickenpox to someone who hasn't had chickenpox or the chickenpox vaccine.

The virus is spread through skin-to-skin contact with the fluid from the blisters or breathing in virus particles coming from the blisters. If the person gets infected, they will develop chickenpox, not shingles. They could then develop shingles later in life.

If your shingles rash is in the blister phase, stay away from people who haven’t had chickenpox or the chickenpox vaccine and keep your rash covered. If you have shingles, you’re contagious until the rash is dried and crusted over.

Shingles Diagnosis

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

With that said, zosteriform herpes simplex (a form of herpes simplex) can mimic shingles. It can 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 (makes multiple copies) viral DNA.

Treatment for Shingles

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 some evidence, albeit weak, that it may help reduce the risk of postherpetic neuralgia as well.

The antivirals commonly used to treat shingles include:

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

Pain can be controlled with medications such as:

• Over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs)
• Topical numbing agents (like lidocaine or capsaicin)
• Prescription medications like Elavil (amitriptyline) and Neurontin (gabapentin)

How to Prevent Shingles

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 two to six months.

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.

When to See a Healthcare Provider

It is important to contact your healthcare provider right away if you notice symptoms so that antiviral therapy can be prescribed. After 72 hours, the benefits of antiviral therapy drop significantly.

If your healthcare provider is not available, access an urgent care facility or telehealth services. Most providers can authorize and prescribe treatment based on the appearance of the outbreak and a quick review of your medical history.

It is particularly important to contact your healthcare provider if:

• The pain and rash occur near an eye.
• You're age 50 or older.
• You or someone in your family has a weakened immune system.
• The rash is widespread and painful.
  

Coping With Shingles

Some people find it difficult to cope with the pain of a shingles 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.

These tips can help you deal with the discomfort of shingles:

• Apply a cool washcloth to blisters to ease the pain.
• Apply an ice pack to the rash. Limit treatment to 15 to 20 minutes several times a day, and always make sure there is a barrier (like a towel) between the ice and your skin.
• 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.

Summary

Shingles is caused by the same virus that causes chickenpox. It usually affects people later in life and causes a painful, blistering rash. Treatment includes antiviral drugs and pain-relieving medications. Shingles can be prevented about 90% of the time with two doses of the Shingrix vaccine. Contact your healthcare provider or an urgent care facility right away if you suspect you have shingles.