Herpes zoster: are you familiar with the symptoms to monitor, the tests to request, or the most suitable treatment?

More than 10% of people will experience herpes zoster (shingles) in their lifetime. Post-herpetic neuralgia can have a devastating impact on the quality of life of some of these people. Healthcare professionals need to know the correct diagnosis and management of this common complaint. Test your knowledge in this quiz.

Primary infection with varicella zoster virus in susceptible individuals causes varicella (chickenpox), which is normally self-resolving in healthy children whose immune system controls the infection. Varicella zoster virus establishes a latent infection within ganglionic neurons. As cellular immunity to varicella zoster virus decreases with advancing age (immunosenescence), or in immunocompromised people, the virus may reactivate, and spread to the skin, innervated by these neurons, where it causes herpes zoster.

A herpes zoster diagnosis can be confirmed by serological testing for herpes zoster antigens; PCR or direct fluorescent antibody testing can also provide a herpes zoster diagnosis. However, serology for herpes zoster-specific antibodies is recommended only in specific situations; for example, to differentiate from herpes simplex, or to diagnose herpes zoster without skin manifestations (herpes zoster sine herpete). Glycoprotein E can be used as an antigen specific to herpes zoster to differentiate between herpes zoster virus and herpes simplex virus.

Pain associated with herpes zoster tracks three common phases:

• Acute herpetic neuralgia, which persists for approximately 30 days
• Subacute herpetic neuralgia, persisting between one to three months
• Post-herpetic neuralgia (PHN); pain persisting over three months following disease onset

Pain associated with herpes zoster can be burning paroxysmal, spontaneous, or touch-triggered allodynia to mild or normal external stimuli (either dynamic or static), or general hyperalgesia in the affected skin region. PHN is painful and burdensome, which can compromise patient function and quality of life, and is perhaps the most feared complication of herpes zoster.

Antiviral treatment is most effective when initiated within 72 hours post-onset of herpes zoster symptoms, especially in patients with severe disease. Antiviral agents may benefit the patient as long as new lesions are actively being formed, but they are unlikely to help once lesions have crusted.

Antiviral treatment can shorten the duration of herpes zoster viral shedding, stop the formation of new lesions, prevent ocular complications, and reduce the severity of acute pain. Antiviral treatment is recommended in people with herpes zoster, regardless of site, patients with severe disease or evidence of trigeminal nerve involvement (head or neck region), and all immunocompromised patients.

Approval in Europe of recombinant zoster vaccine for the prevention of post-herpetic neuralgia (PHN) was based on efficacy and safety data from the Phase III placebo-controlled trials (ZOE-50 and ZOE-70). Overall vaccine efficacy against herpes zoster was up to 97.2% in participants aged ≥50 years, and up to 89.8% in those aged ≥70 years. Vaccine efficacy against PHN was 88.8% in participants aged ≥70 years, and efficacy against herpes zoster was maintained at 87.9% four years after vaccination.

Benjamin Hidalgo-Matlock
Skin Care Physicians of Costa Rica

Clinica Victoria en San Pedro: 4000-1054
Momentum Escazu: 2101-9574

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