The virus which causes chicken pox and SHINGLES. Shingles receives its name from the Greek word for a ‘circingle’ or girdle, because it spreads in a zone-like manner along the intercostal nerves around half the chest. Herpes of the face also occurs, particularly on the brow and around the eye.
Shingles is due to the same virus that causes chickenpox. This invades the ganglia of the nerves, particularly the spinal nerves of the chest and the fifth cranial nerve which supplies the face. Despite being due to the same virus as chickenpox, it is rare for herpes zoster to occur as a result of contact with a case of chickenpox. On the other hand, it is not unusual for a patient with herpes zoster to infect a child with chickenpox. It is a disease of adults rather than children, and the older the person, the more likely he or she is to develop the disease. Thus in adults under 50, the incidence is around 2.5 per 1,000 people a year; between 50 and 60 it is around 5 per 1,000; whilst in octogenarians it is 10 per 1,000. Occasionally it may be associated with some serious underlying disease such as LEUKAEMIA, LYMPHADENOMA, or multiple MYELOMA.
The first symptoms are much like those of any feverish attack. The person feels unwell for some days, has a slight rise of temperature, and feels vague pain in the affected site. Often this site feels hypersensitive (hyperaesthesia), as though something were rubbing on it. The pain finally localises and, two or three days after the first symptoms, the rash appears. Minute yellow blebs (vesicles) are seen on the affected area; these increase in number for some days, and spread until there is often a complete half-girdle around one side of the chest. The pain in this stage is severe, but it appears to vary a good deal with age, being slight in children and very severe in old people, in whom herpes may form a serious illness. After one or two weeks, most of the vesicles have dried and formed scabs. The pain may not pass off when the eruption disappears, and may remain for weeks or even months – a condition known as post-herpetic NEURALGIA.
ACICLOVIR or famciclovir can be given orally, and are effective if started in large doses early in the attack. Later, topical antibiotics may be required. Analgesics may be necessary if neuralgia is severe. In the UK, immunisation against the virus is offered to those over 65.