Shingles (Herpes Zoster)

– An acute, central nervous system infection involving the dorsal root ganglia that is characterized by vesicular eruption and neuralgic pain in various areas of the skin.

Causes and Incidence

Shingles is caused by the varicella-zoster virus, the same virus that causes chicken pox. It is theorized that the virus lies dormant in the dorsal root ganglia after a chicken pox outbreak and is reactivated by local trauma, acute illness, emotional stress, systemic disease (particularly Hodgkin’s disease), immune system compromise, or immunosuppressive therapy. About 3% of the U.S. population has shingles. Individuals over 50 years of age and people who are HIV positive are more likely to develop the disease.

Disease Process

The reactivated virus travels from the dorsal root ganglia down the sensory nerve and inflames and infects the skin of the affected ganglion.

Symptoms

Prodrome
Chills, fever, malaise, gastrointestinal upset 3 to 4 days before eruption

Eruptive phase
Crops of vesicles on an erythematous base appear on the skin above the affected dermatome with hyperesthesia, severe pain, burning, and itching; after day 5 the lesions dry out and crust over and may scar as they heal

Postherpetic phase
Neuralgia that may persist for months or years

Potential Complications

Herpes zoster ophthalmicus may result in vision loss. A generalized outbreak of shingles may lead to acute urinary retention and unilateral paralysis of the diaphragm. In rare cases shingles may be complicated by central nervous system infection, muscle atrophy, transient paralysis, and ascending myelitis.

Diagnostic Tests

Physical examination
Characteristic lesions

Cytologic smear
Direct identification of multinucleated cells

Culture
Varicella virus in vesicular fluid

Treatments

Surgery
None.

Drugs
Analgesics for pain; antipruritics for itching; antiviral agents for immunocompromised individuals and the elderly during eruptive phase to accelerate healing and reduce neuralgia; tranquilizers for severe neuralgia.

General
Wet compresses on lesions; avoidance of scratching and spread to other body regions; cryotherapy or transcutaneous electrical nerve stimulation for neuralgia.