Shingles is a result of the same virus that causes chickenpox.
Shingles or herpes zoster (HZ), which is also known as the “snake” in local vernacular, is an infection of a nerve and the surrounding skin by the varicella-zoster virus (VZV), which also causes chickenpox.
After a chickenpox infection, VZV does not disappear but remains inactive in the body. The virus is reactivated when the body’s immunity is weakened, e.g. increasing age, stress, chemotherapy for cancer, HIV/AIDS, recent organ or bone marrow transplant.
HZ cannot be transmitted to adults who have had chickenpox before. However, it is possible for someone who has not had chickenpox previously to get infected from direct contact with fluid from the blisters of a person who has shingles, as they contain live viral particles.
When the blisters have dried and formed scabs, the sufferer is no longer infectious. This usually takes 10 to 14 days.
A shingles attack usually lasts from two to four weeks, with the main symptoms being pain followed by a rash. It can affect any part of the body, with the chest and abdomen the most common areas.
Some may experience early symptoms, which occur a few days before the painful rash. They include a headache; burning, tingling, numbness or itchiness of the skin in the affected area; feeling unwell; and fever.
Eventually, most have a localised band of pain. The affected skin is usually tender to the touch. The pain usually occurs a few days before the rash appears, and can remain for days or weeks after the rash disappears.
The pain is more severe and lasts longer in the elderly.
The rash usually appears on one side of the body on the skin area supplied by an affected nerve. It appears as red blotches initially, and then develops into itchy blisters similar to those in chickenpox.
The blisters then flatten, dry out and turn yellowish. Scabs are formed where the blisters used to be, with slight scarring. Complete healing of the rash takes two to four weeks.
Sometimes, complications occur, especially if the one affected is older or immunity is weakened. The complications involve the nerves, skin, eyes and other organs.
Post-herpetic neuralgia (PHN) is the most common complication. It has been estimated that one in five HZ sufferers above the age of 50 years develop PHN. The pain may be constant or intermittent, burning, aching, throbbing, stabbing or shooting.
PHN sometimes take about three to six months to resolve, and may last for years and become permanent. It is more common and severe in senior citizens.
If the eyes are affected, the complications include ulcers and permanent scarring of its surface (cornea); increased pressure inside the eye (glaucoma); and inflammation of the eye and optic nerve, which connects the eye to the brain.
Ramsay Hunt syndrome, which is due to HZ infection of certain nerves in the head, is rare. It causes earache, hearing loss, dizziness, a feeling that the body or environment is moving (vertigo), hearing sounds from inside the body (tinnitus), loss of taste and facial paralysis.
Other rare complications include infections of the lung (pneumonia), liver (hepatitis), brain (encephalitis), spinal cord (myelitis) or the membranes surrounding the brain and spinal cord (meningitis).
Although HZ is rarely life threatening, it has been estimated that it is fatal in about one in every 1,000 cases in adults above 70 years.
There is no cure for HZ. However, early treatment may reduce its severity and the risk of complications.
Medicines to relieve the pain are usually prescribed.
Antiviral medicines are also prescribed to some patients for seven to 10 days. Although these medicines cannot kill HZ, they stop it from multiplying. This reduces the severity and duration of the attack and prevent complications like PHN.
The medicines are most effective when taken within 72 hours of the rash appearing. They may be taken within a week of the rash appearing in those who are at risk of severe HZ or its complications, i.e. those above 50 years, HZ affecting the eyes, moderate to severe pain or rash, and weakened immunity.
A vaccine against HZ recently become available. Studies have shown that the vaccine reduces the incidence of HZ and PHN; the severity of acute pain; and HZ’s interference with activities of daily living in adults above 50.
The vaccine has been reported to be efficacious for up to 10 years. The incidence of serious side effects is less than 0.1%.
The vaccine has been recommended for adults above 60 years, and may also be prescribed for adults above 50 years.
If you have a HZ rash, avoid swimming, contact sports or sharing towels. This will prevent spread to anyone who has not had chickenpox, which is especially dangerous for the pregnant, infants less than a year, and those with weakened immune system.
If the rash is oozing fluid, it is advisable to avoid work or school.
When the blisters have dried and formed scabs, the sufferer is no longer infectious and does not need to avoid anyone.
Dr Milton Lum is a member of the board of Medical Defence Malaysia. This article is not intended to replace, dictate or define evaluation by a qualified doctor. The views expressed do not represent that of any organisation that the writer is associated with.