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An in-depth report on the causes, diagnosis, treatment, and prevention of shingles and chickenpox.
Chicken pox; Herpes zoster; Postherpatic neuralgia
The time between exposure to the virus and eruption of symptoms is called the incubation period. For chickenpox, 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 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 (sprout), 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, the entire disease process lasting 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.
Shingles nearly always occurs in adults. It develops on one side of the body. Usually two, and sometimes three, identifiable symptom stages occur:
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).
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.

The active infection is typically marked by the following sequence:
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. PHN occurs in about 10 - 20% of patients who have shingles.
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