Shingles or herpes zoster is due to the same virus which causes chickenpox, or varicella.
It is believed that the virus does not disappear after an attack of chickenpox but remains in the body, lying dormant in the nerve cells of the posterior horn of the spinal cord or in the posterior ganglia, collections of nerve tissue at the side of the spinal cord.
These cells, in the back part of the cord, are concerned with sensation. The anterior horn cells, at the front of the cord, are related to motor function. Some years later the virus multiplies, becomes active, and produces the condition of shingles.
The closely related virus of herpes simplex, which causes the common cold sore, behaves in the same way. It is difficult to eradicate from the body and may flare up from time to time.
Shingles develops only in those who have previously had chickenpox. When somebody has shingles, then susceptible people like his or her grandchildren may develop chickenpox if they are in contact.
The reverse does not appear to happen, but herpes zoster may be more common when chickenpox is prevalent in the community. Although we are not certain what activates the dormant virus, it could be a re-infection overcoming the body’s immunity.
Shingles may occur at any age, even in children. However, the younger the person the less likely are complications. The frail and the elderly may suffer greatly from this condition and then it is more likely to be followed by persistent inflammation of the nerves and severe pain or neuralgia.
The attack may be accompanied by a fever that lasts for two to four days, and there may be typical virus infection symptoms such as aches and pains and tiredness. The lymph glands in the area may be enlarged and tender. Pain may be felt in the area supplied by the sensory nerve and mistaken for a muscular pain or a strain.
Some four to eight days later, the typical rash appears. It starts as a reddening of the skin, then small blisters filled with a clear fluid develop. They dry up and scab, and finally disappear to leave scars which may persist for months or occasionally for years.
If the infection is severe or if the person’s immunity is low, the condition may spread, resulting in a few vesicles like those in chickenpox on other parts of the body. Sometimes the infection can extend along the spinal cord. Occasionally the motor cells of the front of the spinal cord are involved, and this can cause weakness or paralysis of muscles.
The most common area affected is the trunk, when the thoracic part of the spinal cord is involved. But it may affect other areas and the lesions extend down the arm or leg.
Should the ophthalmic branch of the fifth cranial or trigeminal nerve be involved, this can affect the eye. Blisters may form on the cornea, the clear window over the eye, and lead to ulcers and scarring. The inflammation may lead to loss of sensation on the cornea, predisposing it to injury. To protect the cornea it is sometimes necessary to sew the eyelids partially together.
At other times another portion of the nervous system, the geniculate ganglion, is involved and the blisters appear on the ear. This can be associated with vertigo or giddiness and may cause damage to the facial nerve and paralysis of the facial muscles.
In young people the pain is usually not severe and disappears quickly as the rash fades. In older people it may be severe and remain for years afterward.
The pain is usually superficial and burning in character. The skin in the region of the rash is often so sensitive that even the pressure of the clothes may be painful.
There are several false ideas in the community about shingles. It is often thought to be due to “nerves” in the sense of nervous tension.
The infection does involve the actual nerve that conveys sensation, but it has no relation to emotional disorders such as anxiety. It may because of the persistent pain or residual damage to the eye, lead to anxiety and depression after the attack.
Herpes zoster affects only one side of the body. There is an erroneous belief that it can be fatal if it involves both sides and they meet.
The treatment of shingles has never been satisfactory. Many different treatments have been tried, but few have stood the test of time. Various vitamins have been used with little success.
For some years the enzyme protamide was used, and injections were claimed to reduce the inflammation and relieve the symptoms.
They were supposed to be given early in the course of the illness, but few patients go to their doctor when the only symptom is pain. At this stage it is hard to make the diagnosis, as the pain could be due to many things. Once the rash has developed the diagnosis is obvious, but by this time this injection produces little benefit.
For some time it was claimed that X-ray therapy on the spinal cord could reduce the pain after an acute attack, but this has not proved so. Various types of surgical procedures have produced little benefit.
In the initial stages, and later, the pain must be relieved. This can be done with the normally available pain-relieving drugs. Care must be exercised with the narcotic drugs such as morphia, as dependence may develop. Local applications are of little use. Zinc oxide powder dusted on the lesions may relieve the local irritation, keep it dry, and help prevent infection.
Cortisone is now regarded as the most effective means of relieving the inflammation.
Herpes zoster is a common disorder in our community. It appears of little consequence to the young but maybe a distressing problem for the elderly.