At a glance
- Herpes zoster, or “shingles,” is caused by a reactivation of varicella-zoster virus lying dormant in the sensory ganglia.
- Herpes zoster has a characteristic prodrome stage marked by pain,
tingling, itching, and burning.
- Zostavax, a new live attenuated zoster vaccine, is recommended prophylactically for adults aged 60 years and older.
- Zostavax has been shown to be effective in preventing herpes zoster but is not indicated for treatment of herpes zoster or postherpetic neuralgia.
With the aging of the U.S. population, the number of herpes zoster (HZ), or shingles, cases is increasing dramatically. Lifetime incidence of HZ, a reactivation of varicella-zoster virus (VZV) lying dormant in the sensory ganglia, is estimated at 10%-20%; the incidence in people aged 85 and older is as high as 50%.1
The pain of postherpetic neuralgia (PHN), often described as burning, throbbing, or aching, is frequently the most debilitating aspect of HZ. Pain syndromes may result in chronic fatigue, sleep disorder, and psychiatric disorders, such as depression or anorexia. In the elderly, pain from PHN disrupts basic activities of living, such as dressing, bathing, and walking.1 A substantial subset of elderly patients with HZ is refractory to treatment and has a poor prognosis for PHN relief. In these patients, pain often worsens over time. The incidence and severity of HZ are also higher among immunocompromised individuals. Those with HIV/AIDS have a 12- to 17-fold greater risk of developing HZ; the incidence in patients with hematologic malignancies ranges from 5% to 25%.
Clinical presentation and treatment
HZ has a characteristic prodrome stage marked by pain, tingling, itching, and burning. Patients may also have a mild, viral-like syndrome with fever and malaise. Depending on its location, the pain can be so severe that HZ may be mistaken for other serious conditions, including MI, cholecystitis, muscle pain, and migraine. The eruption of HZ is a unilateral rash in one or two dermatomes. The rash, which is maculopapular at first and then becomes vesicular, most often has an erythematous base. Lesions evolve over 7-10 days and heal over two to three weeks.
Antiviral therapy should ideally begin within 72 hours after the initial outbreak. Studies show that antiviral therapy shortens the duration of the outbreak by one to three days compared with placebo and that acute pain resolves more rapidly with these medications.2,3
Three antiviral agents are available for HZ: acyclovir, famciclovir, and valacyclovir. Because of their greater bioavailability and ease of use compared with acyclovir, famciclovir and valacyclovir have become the standard treatment for HZ. Antiviral treatment cannot prevent PHN. However, a randomized, double-blind, controlled trial showed that famciclovir can reduce PHN duration. Immunocompetent patients who had uncomplicated HZ (N=419) were assigned to a seven-day course of famciclovir 500 mg or 750 mg or placebo t.i.d. Lesions were assessed until full crusting occurred and then weekly until healing. Pain was assessed monthly for five months after lesions healed. Famciclovir accelerated lesion healing while shortening the period of viral shedding by one to two days and the median duration of PHN by approximately two months.3
In the acute phase of HZ, minor pain may be treated with analgesics, nonsteroidal anti-inflammatory drugs, or antihistamines. For many patients, these medications do not suffice. Other options include anticonvulsants, tricyclic antidepressants, and anesthetics.