Herpes zoster (shingles) is an acute unilateral and segmental inflammation of the dorsal root ganglia. It produces localized vesicular skin lesions confined to a dermatome. The patient with shingles may have severe neuralgic pain in the areas bordering the inflamed nerve root ganglia.
The infection is found primarily in adults between ages 50 and 70. The prognosis is good, and most patients recover completely unless the infection spreads to the brain. Herpes zoster is more severe in the immunocompromised patient but seldom is fatal. Patients who have received a bone marrow transplant are especially at risk for the infection.
After the chickenpox virus has been contracted, it travels from the skin along the nerve paths to the roots of the nerves where it becomes inactive. The chickenpox virus then 'hibernates'. When the virus is reactivated, it travels via the nerve paths to the skin. It is not known what factors trigger a reactivation of the virus. Shingles generally affects the elderly, but occasionally occurs in children who have had chickenpox within the first year of their lives and in people with an immune deficiency.
Symptoms and Signs
Symptoms that may be associated with this disease:
Vesicular fluid and infected tissue analyses typically show eosinophilic intranuclear inclusions and varicella virus. Differentiation of herpes zoster from localized herpes simplex requires staining antibodies from vesicular fluid and identification under fluorescent light. Usually, though, the locations of herpes simplex and herpes zoster lesions are distinctly different.
With CNS involvement, results of a lumbar puncture indicate increased pressure, and cerebrospinal fluid analysis demonstrates increased protein levels and, possibly, pleocytosis.
Oral acyclovir therapy accelerates healing of lesions and resolution of zoster-associated pain. Famiciclovir is also very effective, as is valacyclovir. In the immunocompromised patient, herpes zoster should be treated with I. V. acyclovir. Therapeutic goals include relief of itching with antipruritics (such as calamine lotion) and relief of neuralgic pain with analgesics (such as aspirin, acetaminophen or, possibly, codeine). Tricyclic antidepressants help relieve neuritic pain. A similar goal involves preventing secondary infection by applying a demulcent and skin protectant (such as collodion or tincture of benzoin) to unbroken lesions.
If bacteria infect ruptured vesicles, treatment includes an appropriate systemic antibiotic. Herpes zoster affecting trigeminal and corneal structures calls for instillation of idoxuridine ointment or another antiviral agent.
To help a patient cope with the intractable pain of postherpetic neuralgia, a systemic corticosteroid, such as cortisone or corticotropin, may be ordered to reduce inflammation. The doctor also may order tranquilizers, sedatives, or tricyclic antidepressants with phenothiazines.
As a last resort for pain relief, transcutaneous peripheral nerve stimulation, patient-controlled analgesia, or a small dose of radiotherapy may be considered.
People who have never had chickenpox can reduce the risk of getting the virus by avoiding contact with people with chickenpox and shingles. Shingles itself is not preventable.
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