III.

Herpes Zoster

Known as shingles, herpes zoster is a recurrence of the symptoms of chickenpox, usually during adulthood. It is caused by the chickenpox virus attacking a sensory nerve. The skin over the nerve generally breaks out in blisters a few days after the onset of the disorder, which is accompanied by pain and frequent numbness or hypersensitivity along the course of the nerve, usually the trunk. The blisters are at first clear, but become cloudy within a few days and form crusts that dry up after five or ten days.

The skin manifestation of herpes zoster is not serious, but the pain caused by the inflammation of the underlying nerve can be severe, lasting for weeks; recovery may be followed by persistence of neuralgia in the area of the involved nerve. High doses of acyclovir can significantly reduce the symptoms of herpes zoster. Normally, medication relieves pain, and the disease subsides spontaneously. More severe cases may be treated with such steroids as cortisone. In cases of persistent pain, the involved nerve may be either blocked by drugs or cut.

In people with cancer being treated with drugs, herpes zoster infections can be fatal. Japanese scientists have developed a vaccine with which they have inoculated children being treated for leukaemia. Their results indicate that the vaccine is safe and that it prevents severe herpes zoster infection in these patients.

Herpetic infections of the eye, called dendritic keratitis, can cause scarring of the cornea. They are treatable with idoxuridine and vidarabine.