Herpes Zoster Infection
- What is herpes zoster infection?
- Other names for herpes zoster infection
What is herpes zoster infection?
Herpes zoster infection, often known as shingles, is a common viral infection. Around one in three people in the United States will develop shingles in their lives, with 1 million cases in the country each year.
Herpes zoster infection is more likely to affect older people and people with a weak immune system. It causes a burning pain, followed by a blistering rash, which tends to only affect one area of the body. If you think that you might have shingles, you can try using the Ada app to find out more about your symptoms.
Shingles is treated with antiviral medications. The rash will usually begin to get better within two weeks, and although most people recover well, some may be left with persistent pain in the affected area. Effective pain management from the early stages is therefore very important.
People with shingles should avoid contact with people who have not been vaccinated against chickenpox and people who have a weakened immune system.
Symptoms of herpes zoster infection
The most commonly known symptom of shingles is the rash. Where the rash appears will depend on what part of the body the herpes zoster virus has been dormant in. The rash appears on the dermatome associated with the affected nerve. The rash is most common on the chest, back, shoulders or face. Pain and the accompanying rash can occur anywhere on the body, depending on which nerve is affected by the infection.
- The rash is vesicular; vesicles are small, blister-like sacs that appear on the surface of the skin
- The skin around the vesicular rash becomes red
- The rash is generally confined to one area of the body in a stripe-like pattern; usually one side of the body or, in some cases, the face. In immunosuppressed people the rash may be more widespread
- The rash blisters burst and scab over, usually seven to 10 days after first appearing
- The rash generally goes away after two to four weeks
Most people will only experience shingles once, though less than 4 percent will have another episode. If you are concerned that you might have shingles, you can try using the Ada app for a free assessment.
Causes of herpes zoster infection
People at risk of developing shingles are those who have had chickenpox in the past. Herpes zoster infection occurs years, often decades, after a person has been infected with the varicella zoster virus that causes chickenpox.
The virus remains dormant in the body in the ganglia[^7] of the sensory cranial nerves and spinal dorsal root. If a person’s immunity to varicella zoster weakens over time, either due to age or if a person is immunosuppressed, the virus can reactivate. This reactivation is called herpes zoster infection, or shingles.
Conditions and situations that can suppress the immune system and make someone more at risk of developing shingles include:
- Receiving chemotherapy
- Having the spleen removed
- Hypogammaglobulinemia, a condition where the body does not make enough antibodies
Diagnosis of herpes zoster infection
A diagnosis can usually be made based on the symptoms and the appearance of the rash. If there is uncertainty, the diagnosis can be confirmed with blood tests or by taking a sample of fluid from a blister and testing for the virus.
Complications of herpes zoster infection
Shingles can cause complications if it affects the eye and the ear. It can also cause long-lasting pain even after the rash has gone.
Herpes zoster ophthalmicus
Herpes zoster ophthalmicus, or ophthalmic shingles, is a variant of shingles where the virus affects the ophthalmic nerve and eye. If not treated quickly, it has the potential to cause permanent vision problems.
Herpes zoster oticus
Herpes zoster oticus, or Ramsay Hunt syndrome, occurs when the herpes zoster virus affects facial nerves. It is a rare form of shingles that causes pain deep within the ear and facial palsy as well as the rash. With treatment, most people will recover full use of facial nerves.
Some people infected with herpes zoster will continue to feel pain in the affected areas of the body. Pain that persists for three months or longer is called postherpetic neuralgia (PHN).
Postherpetic neuralgia pain is caused by damage to nerves during the shingles infection. It is more common in older people, rising to 20 percent of people 80 years and older experiencing PHN after shingles.
Symptoms and effects of postherpetic neuralgia include:
- Sharp pain
- Intermittent or constant pain
- Allodynia, which is pain caused by light touches or the feel of clothing on skin
- Difficulty sleeping
The experience of living with PHN may bring on clinical depression.
Treatment of herpes zoster infection
Herpes zoster infection is usually treated with antiviral medication in people who are immunocompetent. These drugs helps shorten the duration and lessen the severity of shingles by easing the associated pain and promoting healing of the blisters. Medication should be taken as soon as possible after the rash appears.
- Acyclovir: taken orally, acyclovir has been the traditional antiviral for use in shingles treatment. However, other drugs have been developed which can be taken less frequently and are better absorbed by the body
- Famciclovir: taken orally, famciclovir converts to the compound penciclovir which is effective against the varicella zoster virus
- Valacyclovir: taken orally, valacyclovir treats pain and itching and helps sores to heal while preventing new sores forming
- Upset stomach
- Painful menstruation
Some doctors may prescribe steroid tablets to reduce swelling and itching, but this is not recommended in most cases. Anti-inflammatory medications, such as ibuprofen, or other analgesics, may also help to reduce the pain and swelling.
People with shingles should try to avoid scratching at the rash. Calamine lotion and wet compresses can help soothe the itching.
Treatment of herpes zoster infection in the immunosuppressed
- The rash spreading across the body
- Infection of the lesions, usually due to Staphylococcus aureus
- Deafness caused by herpes zoster oticus
It is even more important to treat immunosuppressed people with antiviral drugs to limit complications, potentially requiring hospitalization to administer drugs intravenously. The antiviral drugs are the same as those given to immunocompetent people.
Treatment of postherpetic neuralgia
Early prescription of painkillers to people with herpes zoster infection is advised to try and prevent the development of postherpetic neuralgia. Types of painkiller prescribed may include:
- Paracetamol (acetaminophen)
If postherpetic neuralgia develops, it can be treated with:
- Topical creams, such as lidocaine and capsaicin, to ease pain and allodynia in particular
- Antidepressants, such as tricyclics or selective serotonin and norepinephrine reuptake inhibitors to relieve pain and counter effects of clinical depression
- Anticonvulsants, such as pregabalin or gabapentin, to relieve neuropathic pain
Prevention of herpes zoster infection
People who have shingles should keep away from people who have not been vaccinated against chickenpox, especially newborns, and people who have a weak immune system. Although shingles itself cannot be passed from person to person, the varicella zoster virus which causes chickenpox can be transmitted by contact with the fluid in the rash blisters.
Vaccination for herpes zoster infection
Vaccination against chickenpox (the varicella vaccination) and herpes zoster (a herpes zoster vaccination) can help to prevent and reduce the severity of some cases of shingles.
The Centers for Disease Control recommends that all healthy adults aged 50 and older should receive a shingles vaccine. Depending on the age of the person receiving the vaccine, it is between 89 and 97 percent effective at preventing shingles and postherpetic neuralgia.
FAQs for herpes zoster infection
Q: Is herpes zoster contagious?
A: Herpes zoster itself is not contagious. However, it is possible for someone with shingles to pass on the varicella virus that causes chickenpox through contact with fluid from the rash blisters.
Other names for herpes zoster infection
Dermatome: the area of skin supplied by a nerve. ↩
Sensory cranial nerves: the nerves in the head which are responsible for sensations such as sight and smell. ↩
Spinal dorsal root: there are 31 pairs of spinal nerves along the vertebrae. The dorsal roots contain sensory fibers. ↩
US National Library of Medicine. “Herpes Zoster (Shingles) and Postherpetic Neuralgia.” March 2009. Accessed May 15, 2018. [^7] Ganglia: a cluster of nerve cells. ↩ ↩ ↩
Immunocompetent: a person with a normal immune system. ↩
UpToDate. “Treatment of herpes zoster in the immunocompetent host.” April 2018. Accessed May 15, 2018. ↩