Shingles and chickenpox (Varicella-zoster virus)
Description
An in-depth report on the causes, diagnosis, treatment, and prevention of shingles and chicken pox.
Alternative Names
Chicken pox; Herpes zoster; Postherpatic neuralgia
Symptoms
The time between exposure to the virus and eruption of symptoms is called the incubation period. For chicken pox, this period is 10 - 20 days. The patient often develops fever, headache, swollen glands, and other flu-like symptoms before the typical rash appears. While fevers are low grade in most children, some can reach up to 105° F.
These symptoms subside once the rash breaks out. One or more tiny raised red bumps appear first, most often on the face, chest, or abdomen. They become larger within a few hours and spread quickly, eventually forming small blisters on a red base. The numbers of blisters vary widely. Some patients have only a few spots, others can develop hundreds. Each blister is filled with clear fluid that becomes cloudy in several days. It takes about 4 days for each blister to dry out and form a scab. During its course, the rash itches, sometimes severely. Usually separate crops of blisters occur over 4 - 7 days, and the entire disease process lasts 7 - 10 days.
Chickenpox itself usually occurs only once, although mild second infections, marked by the telltale rash, have been reported in older children years after their first infection.
Symptoms of a Typical Shingles (Herpes Zoster) Attack
Shingles nearly always occurs in adults. It develops on one side of the body. Usually two, and sometimes three, identifiable symptom stages occur:
-
The first is known as the
prodrome
, a cluster of warning symptoms that appear before the outbreak of the infection.
-
The second stage comprises the symptoms of the
active infection
itself.
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In many patients, a third syndrome known as
postherpetic neuralgi
a develops.
One form of shingles is known as zoster sine herpes, in which pain occurs first without a rash. Pain is so common to all stages of herpes zoster that doctors often refer to all syndromes with a single term: Zoster-Associated Pain (ZAP).
Prodrome (Pain)
.
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Pain is the primary early symptom for shingles, and it occurs in all patients. The pain most often occurs in the skin at the site of the re-activated virus. The pain may be experienced as sharp, aching, piercing, tearing, or similar to an electric shock.
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The affected skin may itch, feel numb, and be unbearably sensitive to touch. Often the patient experiences a combination of these sensations along with pain.
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In addition, some patients may have flu-like symptoms such as muscle aches. (Some people have fever, but it is uncommon.)
The prodrome stage lasts 1 - 5 days before the infection becomes active and the skin rash erupts. Occasionally, the pain can last weeks or even months before the rash erupts.
Active Shingles.
The rash that marks the active infection follows the same track of inflamed nerves as the prodrome pain. Between 50 - 60% of cases occur on the trunk. The second most common site is the head, particularly on one side of the face. It may also erupt on the neck or lower back. If the face is affected, there is a danger that the infection can spread to the eye or mouth. A rash that follows the side of the nose is a warning that the cornea of the eye is in danger.
This is a picture of herpes zoster (shingles) on the neck and cheek. The same virus that causes chickenpox is responsible for outbreaks of shingles. Outbreaks of shingles often follow the distribution of nerves in the skin. This distribution pattern is called a dermatome (see the "dermatomes" picture).
The active infection is typically marked by the following sequence:
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A rash appears, starting as well-defined, small, red, clear spots.
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Within 12 - 24 hours, these pimples develop into small fluid-filled blisters.
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The blisters grow, merge, and become pus-filled.
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Pain is common during the active infection.
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Within about 7 - 10 days (as with chickenpox), the blisters form crusts and heal. In some cases it may take as long as a month before the skin clears completely. Healing takes even longer in patients who have impaired immune systems, and, in such cases, the blisters may persist for months.
Zoster Sine Herpete.
Sometimes pain develops without a rash, a condition known as
zoster sine herpete
. This usually occurs in elderly patients. Symptoms include burning or shooting pain, numbness, tingling, itching, headache, fever, chills, and nausea. An accurate early diagnosis of shingles in such cases is often difficult. Some evidence suggests that some cases of Bell's palsy (in which part of the face becomes paralyzed) might actually be an indication of zoster sine herpete.
Postherpetic Neuralgia.
Postherpetic neuralgia (PHN) is pain that persists for longer than a month after the onset of herpes zoster. (Some experts define persistent pain as subacute herpetic neuralgia if it lasts between 1 - 3 months, and as PHN if it lasts beyond 3 months.) PHN occurs in approximately 10 - 20% of patients who have shingles.
Risk for Recurrence of Shingles.
Shingles can recur, but the risk is low (1 - 5%). Some evidence suggests that a first zoster episode boosts the immune system to ward off another attack. To support this theory, some elderly people with zoster who are exposed to children with chickenpox appear to have extra protection against a second zoster attack. In people with impaired immune systems, such as those with AIDS, a booster effect does not occur. These patients are at particular risk for multiple recurrences of shingles.
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Review Date: 3/15/2007
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Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital.
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