Shingles (Herpes Zoster): Symptoms, Causes, Risks, Complications, Diagnosis, Treatment and Prevention

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Shingles (Herpes zoster)

 

1Overview

Shingles is a painful rash that is often accompanied by blisters. It is also called herpes zoster. A shingles rash usually manifests on just one side of the face, or one side of the body, and lasts for 2-4 weeks. The main symptom of shingles is a pain, which is often severe. Other symptoms may include chills, fever, headache, and an upset stomach. Rarely, however, an infection of shingles can lead to brain inflammation, hearing problems, pneumonia, blindness, or even death.

In 1 out of 5 people with shingles, severe pain can continue even when the rashes have already disappeared. This is termed as post-herpetic neuralgia. Shingles is an infection caused by the varicella zoster virus, which is the same virus that causes chicken pox.

Only people who have had chickenpox, or been injected with the vaccine against chickenpox, can get shingles. The virus from the vaccine can stay in the body for years and eventually cause shingles.

Shingles is not a contagious disease even if it is viral. Thus, an infected person cannot transmit the infection to someone else. However, a person who has never had chickenpox or who have never been vaccinated with chickenpox vaccine can get chickenpox from someone with shingles. This is due to the fact that the same virus causes the two conditions. However, this is not very common.

Shingles is more common in people who are older than 50 years compared to young people. It is also more common among people with a weakened immune system because of diseases such as AIDS, cancer, or drugs such as those needed to treat cancer. It may also be due to steroids or chemotherapy. At least 1 million people from the United States get shingles every year.

2Symptoms

The first sign that a person has shingles is when they feel a sharp, burning pain on one side of the face or body. They may also feel tingling or numbness in place of pain. The most common location for rashes is the upper abdomen or the back. Alternatively, severe itching may be felt instead of pain. Fever, chills, an upset stomach, and headache may also be felt.

After several days, groups small, clear lumps filled with fluid emerge on reddened skin. They look similar to the rashes that people get from chickenpox since both diseases share the same causative agent. These blisters generally last from 2-3 weeks. During this time, they become yellow and encrusted. Then, they finally begin to disappear.

Usually, there is no scarring associated with having shingles. However, they may leave small, pitted scars on occasion. Once the blisters have healed, some people may experience pain for a prolonged period of time, such as a month or longer.

The degree of discomfort and pain caused by the varicella zoster virus varies. Usually, in younger people, the sores become itchy. A burning sensation may be felt as they heal. In older people, shingles can mean that they will be in pain for a few weeks or even longer as the blisters start to heal. In this instance, the slightest contact, such as a touch, or with clothing, or with the wind, can be unbearable.

3Causes

The causative agent for shingles and chickenpox is the varicella zoster virus. Primary infection with the virus leads to varicella. The virus becomes latent, or it stays inactive in the body, in the dorsal root ganglia of the central nervous system after the first infection. At a later time, it reactivates, causing shingles. It is unclear how or why the virus reactivates in some people and remains dormant in others.

4Risk Factors 

There are a number of well-known risk factors for acquiring shingles or reactivating the varicella zoster virus. One is increasing age. Shingles is more common in older people compared to those who are younger. This may also be due to a weakened immune system, which is another risk factor.

Immunosuppression, or a weakened immune system, is one of the most prominent risk factors for shingles. People who have solid organ and bone marrow transplantation are at risk, especially after surgery. They may be prescribed steroids that weaken the immune system. Patients with malignancies or tumors may also be at an increased risk, especially if they are undergoing chemotherapy. Chemotherapy weakens the immune system as well. HIV/AIDS patients are vulnerable to the virus because HIV is an autoimmune disease that attacks the person’s own immune system. Likewise, drugs that suppress the immune system also place people at risk for shingles.

Females are also at an increased risk for shingles, although the reason remains unknown. Shingles is more prevalent in older females.

The race is another risk factor. Studies have shown that shingles is less common in African Americans compared to whites. Their risk is less than half that of whites.

Shingles affect one area where the nerve supply is distributed, and this is called a dermatome. The rash spreads along this area when the virus is activated. Trauma or surgery on the affected dermatome places a person at risk for activating the virus and thus getting shingles.

Having early varicella illness places the person at an increased risk for pediatric zoster.

5Complications

Shingles have several complications. One of these is post-herpetic neuralgia, which is a pain in the affected dermatome that lasts for greater than 30 days. It occurs in 18-30% of cases. There is also mild to excruciating pain after the rash disappears. The pain may be intermittent or constant, and it seems to be triggered by trivial stimuli. This can disrupt the person’s sleep, work, and mood, reducing his quality of life. It may restrict the person’s activities of daily living, leading to depression and social withdrawal.

Herpes zoster ophthalmic is another complication that occurs in 15% of shingles cases. It can occur when the ophthalmic tract of the trigeminal nerve is affected by the virus. Left untreated, about 50-70% of cases develop sudden ocular complications. This can lead to chronic eye complications, reduced visual acuity, and even blindness in some cases.

Neurologic complications may also be present, such as encephalitis, or brain infections, cranial nerve palsies, and ischemic stroke syndrome.

Dermatologic complications are minor and they are rare. However, when they occur, they manifest as infections of the blisters themselves. This can lead to persistent scarring and changes in the color of the skin.

6Diagnosis

The diagnosis of shingles can be done by an infectious disease doctor. Often, the doctor will conduct a physical exam on the patient, checking the affected dermatome. If the symptoms that the patient is experiencing are atypical, additional testing may be necessary. Laboratory testing for the varicella zoster virus is done in these cases. This will confirm a clinical diagnosis of shingles and lead to a definitive diagnosis. It can also help the doctor differentiate between the varicella zoster virus from the chickenpox vaccine and from the wild-type strains of the virus.

It is usually diagnosed clinically when a dermatomal rash appears and when prodromal pain is present. The distribution is usually characteristic. However, rashes in other areas, such as the mouth or genitals, should alert the physician to a differential diagnosis. The differential diagnoses for shingles include dermatitis herpetiformis, candidiasis, herpes simplex virus, an autoimmune blistering disease.

Polymerase chain reaction (PCR) may be conducted. Using this test, the viral DNA can be detected. It is the most useful test for the virus because it is both specific and sensitive.

Other tests include direct fluorescent antibody staining, histopathology, and the Tzanck smear. Herpes zoster contains high levels of the varicella zoster virus. The risk of transmitting the virus to unvaccinated individuals can be reduced if the blisters are covered. 

7Treatment 

Antivirals are a group of drugs that can be used to treat viral illnesses like shingles. These include acyclovir and valacyclovir. These are nucleoside analogs that prevent the virus from increasing in number. These drugs are taken orally and they reduce the duration that the virus is shed. They also make the healing process faster and reduce the pain felt by the patient. These drugs are safe and well-tolerated by the majority of patients. Therefore, they should be considered as first-line treatments for shingles. Antivirals are especially recommended for patients above the age of 50, and who have moderate to severe pain due to the blistering and the rash. Antivirals are also recommended for those with facial rashes. These drugs are started within 3 days after a diagnosis is made or after the rashes appear.

Corticosteroids are another treatment option for those with shingles. They are usually given in combination with antivirals. They have a modest effect on the duration and severity of symptoms. However, they are associated with serious side effects, so their utility for treating shingles is often limited. They can only be used in people where no major contraindications to their use are present. Analgesics, or pain killers such as paracetamol, are often given to reduce the pain felt by the patient with shingles.

8Prevention

Vaccines can help prevent shingles. All children should be given two doses of the chickenpox vaccine. Adults who have never had chickenpox should also be vaccinated. The immunization does not mean that a person will never get chickenpox, but it is effective in preventing chickenpox in 9 out of 10 people.