Shingles is a painful skin rash caused by reactivation of prior infection with the same virus that previously caused chickenpox, known as varicella zoster virus (VZV). VZV belongs to the herpes family of viruses, but it is not the same virus that causes genital herpes or cold sores on the mouth.
When a person is infected with VZV in childhood, they typically develop chickenpox, but after the illness resolves the VZV remains in a dormant state in the nervous system and is never fully cleared from the body.
Under certain circumstances, such as emotional stress, immune deficiency (from AIDS or chemotherapy), or with cancer, the virus reactivates and causes the skin and nerve inflammation known as shingles.
Shingles occurs most commonly in people over the age of 60, but anyone who has ever had chickenpox is at risk, including pregnant women. It has been estimated that up to 1,000,000 cases of shingles occur each year in the U.S.
Symptoms of shingles
Shingles is a skin rash characterised by pain and blistering. Tender, painful skin signals the beginning of an attack. The skin then turns red and breaks out in tiny fluid-filled blisters.
Shingles can affect any part of the body, including the face. Classically, the rash caused by shingles takes the shape of a belt or band around or across the body.
The rash forms its characteristic pattern because the virus works down the nerves that branch out from the spinal cord and encircle the body. The chest and stomach are most commonly affected.
The rash can last for a few days or weeks. During that time, a scaly crust might appear. Once the attack is over, the skin usually returns to normal, but there can be some scarring in severe cases.
How shingles is spread
Shingles can be spread when a person comes into contact with fluid contained in the blisters. The virus can be spread by direct contact with the lesions or by touching any dressings, sheets or clothes soiled with discharge from the spots.
Shingles, chickenpox and pregnancy
An attack of shingles during pregnancy will not harm the unborn baby. The mother is already carrying the varicella zoster virus before developing shingles and there is no increase in the risk of passing it on to the fetus if shingles develops.
However, an attack of chickenpox during pregnancy can be serious and requires urgent medical attention.
Sometimes, the pain doesn’t go away once the shingles rash has cleared. This complication is called post-herpetic neuralgia and is more common when the shingles rash appeared on the face rather than the body.
This type of shingles rash tends to affect the skin around the eye and occasionally, the eye itself.
Postherpetic neuralgia can last for months or years. Capsaicin creams can help. Pain-relieving medication or tablets specific for nerve pain may be needed.
Treatment for shingles
Anti-viral medications can help ease the pain and shorten an attack of shingles. The medication works best if administered within three days, and ideally within 24 hours, of the onset of a rash.
If you think you have shingles, seek urgent medical attention.
Analgesic medication may also ease post-herpetic neuralgia, but consult your doctor first.
Shingles and chickenpox vaccination
Chickenpox and shingles vaccines are both available in Australia.
The National Immunisation Program provides free chickenpox vaccine to children aged 18 months of age and as a catch-up dose for adolescents in year 7 of secondary school or age equivalent.
It can also be prescribed by a doctor for older people, but it is not free. People aged 14 years and older require two doses of the chickenpox vaccine, one to two months apart.
People aged 14 years and older must purchase the vaccine privately. The shingles vaccine is also available on prescription for people aged 50 years and over, but it must be paid for by the patient.
How is shingles diagnosed?
The characteristic rash of shingles typically suggests the diagnosis, and in most cases, no specific diagnostic tests are required.
In cases in which there is pain but no apparent rash, the diagnosis can be very difficult. Laboratory testing to detect the genetic material or surface proteins of the VZV can be used in atypical or difficult cases.
What are the complications of shingles in pregnancy?
Postherpetic neuralgia is the most common complication of shingles. This condition develops in about 20% of people who have shingles and is characterized by persistent pain at the affected site after the rash has disappeared.
It goes away by 4 months after the initial rash in most people.
This complication is less common in pregnant women since it rarely occurs in people under 40 years of age. Postherpetic neuralgia is more common in people over 60 who do not receive treatment for shingles.
Shingles that affects the eye is another uncommon condition. It is essential to see a doctor if you develop shingles around the eye area.
In very rare cases, the virus can spread to the brain and membranes around the central nervous system. Other potential complications include hearing or balance problems and weakness of the muscles on one side of the face, known as Ramsay Hunt syndrome.
All of these complications, like postherpetic neuralgia, are more common in older adults and affect pregnant women less commonly.
Sometimes, secondary bacterial infections develop at the site of the rash. These can be treated with antibiotics, and antibiotics can be chosen that are safe for use in pregnancy.
What is the outlook (prognosis) for shingles in pregnancy?
Most cases of shingles heal without a risk of serious complications or long-term problems.
Can shingles in pregnancy be prevented?
If you have had chickenpox in the past, you have been infected with the VZV and there is no absolute way to prevent shingles.
However, you cannot catch shingles from someone else who has shingles or chickenpox if you have had chickenpox or have immunity to the chickenpox virus.
However, pregnant women who have not had chickenpox may catch chickenpox from someone with shingles or chickenpox.
Chickenpox infection during pregnancy can be dangerous to the unborn baby, so it is important to avoid contact with people with shingles or chickenpox if you have not had the condition or the vaccine.
Children in the US today are typically vaccinated against the VZV (chickenpox vaccine). A vaccine to prevent shingles (Zostavax) is also available that reduces the incidence of shingles by about 50%, but the vaccine cannot be taken by pregnant women.
Women who receive the Zostavax vaccine should wait at least 3 months before attempting pregnancy.