The Varicella-Zoster Virus & VZV Infections

The varicella-zoster virus (VZV) is the virus that causes chickenpox, shingles and post-herpetic neuralgia (PHN).

Chickenpox


Chickenpox The varicella-zoster virus (VZV) first strikes as chickenpox or varicella, a highly contagious disease affecting 95 percent of Americans by age 18, or four million individuals annually. Although it is commonly regarded as a mild childhood illness, chickenpox is a significant disease. It usually causes fever, discomfort, loss of appetite, headache and skin lesions, which can leave scars. But it can also lead to hospitalization and, in rare instances, death.

Chickenpox Bacterial skin infections are the most common chickenpox-related complications and they are increasing in number and severity. Other complications include inflammation of the brain (encephalitis) and pneumonia, although these are rare in otherwise healthy people.

According to the Centers for Disease Control and Prevention (CDC), each year in the U.S., chickenpox results in: the hospitalization of nearly 11,000 individuals, the majority of whom are otherwise healthy, and two-thirds of whom are children; and 105 deaths.

Chickenpox is now preventable. In March 1995, following more than a decade of development and testing, the U.S. Food and Drug Administration approved the country's first chickenpox vaccine for use in children and adults who have not had chickenpox. The FDA concluded that the vaccine is safe and effective.


Shingles & PHN

ChickenpoxFollowing an episode of chickenpox, the varicella-zoster virus lies dormant, or asleep, in nerve tissues. However, in an estimated one out of seven people over the course of an 85-year lifetime, the virus can reappear as shingles or herpes zoster. Shingles is an outbreak of a rash or blisters on the skin that can be very painful. The rash and pain usually occur in a band on one side of the body, or clustered on one side of the face.


Shingles In otherwise healthy individuals, shingles may disappear without major consequence in two to four weeks. But the risk of complications from shingles increases with age, weakened immunity (the body's ability to ward off disease) and delay or lack of treatment. Complications include post-herpetic neuralgia (PHN), which can cause debilitating pain that persists for months or even years after the shingles rash has healed. The pain of PHN may be sharp, piercing, throbbing or stabbing, and it may extend beyond the area of the original shingles eruption. The skin may be unusually sensitive to even the lightest touch (as from clothing), to the smallest breeze, and to changes in temperature (either hot or cold).

In addition to PHN, complications affecting vision and/or hearing are possible if shingles appears on the face. For instance, if shingles affects the eye (ophthalmic shingles), the cornea can become infected, resulting in temporary or permanent blindness. In patients with severely weakened immunity, the shingles virus can also spread to internal organs, affecting the lungs, central nervous system and brain.

The National Shingles Foundation estimates that nearly one million individuals are afflicted by shingles each year in the U.S. alone. It is most common among people over the age of 50, as well as among those who have conditions or are undergoing medical treatments that weaken their immune systems. These include: HIV infection; chemotherapy or radiation therapy; corticosteroids; transplant operations; and possibly stress.

Currently, shingles cannot be prevented. However, a major study is underway to determine whether vaccination can decrease the incidence and/or severity of shingles and its complications in adults 60 years of age and older who have had natural chickenpox.

Antiviral drugs can lessen the duration of shingles and lower the risk for PHN if taken within 72 hours after the appearance of the rash. PHN is treated by a variety of pain-relieving approaches: nonsteroidal anti-inflammatory drugs, narcotic analgesics and specific medications for nerve injury-related pain, including certain medications best known for treating depression. In 1999, the FDA approved a lidocaine skin patch for PHN pain.

The effectiveness of treatment for PHN varies widely among patients. If you develop PHN, you may wish to consult a physician who specializes in the treatment of pain; one option is the attending neurologist or anesthesiologist of a leading hospital in your area.

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