Shingles Causes

Medical Author: Melissa Conrad Stöppler, MD
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

Shingles facts

• Shingles is caused by the same virus that causes chickenpox and can be spread to people who have not had chickenpox.
• Shingles, also known as herpes zoster, is not related to the herpes simplex viruses that cause sexually transmitted herpes or oral herpes.
• Shingles may cause pain that can continue after the rash disappears.
• Postherpetic neuralgia, or persistent pain after the rash has disappeared, is the most common complication of shingles.
• Steroids and antiviral drugs can help prevent long-term pain after shingles if they are started within the first two days of the appearance of the rash.
• The Zostavax vaccine is available for people over 60 years of age to reduce the incidence and severity of shingles.

What is shingles? What causes shingles?

Shingles, also known as zoster or herpes zoster, is a skin rash caused by a nerve and skin inflammation from the same virus that previously caused chickenpox. It is a very common condition, affecting about one out of every three people in the U.S. at some point in life. This virus is called the varicella zoster virus (VZV) and belongs to the herpes family of viruses. After an individual has chickenpox, this virus lives dormant in the nervous system and is never fully cleared from the body. Under certain circumstances, such as emotional stress, immune deficiency (from AIDS or chemotherapy), or with cancer, the virus reactivates and causes shingles. In most cases of shingles, however, a cause for the reactivation of the virus is never found. Anyone who has ever had chickenpox is at risk for the development of shingles, although it occurs most commonly in people over the age of 60. It has been estimated that up to 1,000,000 cases of shingles occur each year in the U.S.

The herpes virus that causes shingles and chickenpox is not the same as the herpes viruses that causes genital herpes (which can be sexually transmitted) or herpes mouth sores.

What are shingles symptoms and signs? How long does shingles last?

Even when there is no rash, the pain of shingles may be apparent. Before a rash is visible, the patient may notice several days to a week of burning pain and sensitive skin. When the characteristic rash is not yet apparent, it may be difficult to determine the cause of the often severe pain, particularly if the individual has never had an attack of shingles.

Shingles rash starts as small blisters on a red base, with new blisters continuing to form for three to five days. The blisters follow the path of individual nerves that come out of the spinal cord in a specific "ray-like" distribution (called a dermatomal pattern) and appear in a band-like pattern on an area of skin. The entire path of the affected nerve may be involved, or there may be areas in the distribution of the nerve with blisters and areas without blisters. Generally, only one nerve level is involved. In a rare case, more than one nerve will be involved. Eventually, the blisters pop, and the area starts to ooze. The affected areas will then crust over and heal. The duration of the outbreak may take three to four weeks from start to finish. On occasion, the pain will be present but the blisters may never appear. This can be a very confusing cause of local pain.

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