Postherpetic Neuralgia is the Most Common Complication
Postherpetic neuralgia (PHN) is definitively the most common complication of herpes zoster infection. 1
Evidence from Guidelines
The most recent 2024 guidelines from the Infectious Diseases Society of Taiwan explicitly identify PHN as the most common complication among the potential sequelae of herpes zoster, which also include HZ ophthalmicus, bacterial superinfections, cranial and peripheral nerve palsies, and visceral involvement. 1
The 2007 CDC/ACIP guidelines state that "the most common complication of HZ, particularly in older persons, is postherpetic neuralgia (PHN)," defined as the persistence of sometimes debilitating pain weeks to months after resolution of HZ. 1
Epidemiology and Risk Factors
PHN occurs in a substantial proportion of herpes zoster patients:
- More than 50% of zoster patients over 60 years old will develop PHN 2
- In a pooled analysis of prospective cohort studies, 21.1% of HZ patients aged ≥50 years developed PHN (defined as pain score ≥3 persisting >90 days after rash onset) 3
- The lifetime risk of HZ itself is estimated at 20-30% in the general population 1
Key predictors for PHN development include: 3
- Older age (particularly >60 years)
- Greater severity of pain at rash onset
- Impaired physical and social functioning from acute zoster pain
- Walking problems at enrollment
- Pain interference affecting social relationships
Clinical Impact
PHN is characterized by persistent neuropathic pain that patients may describe as "cold burning pain" in a dermatomal distribution. 4 This condition can be incapacitating, particularly in immunocompromised patients, and may persist for months to years, causing serious morbidity, depression, and substantial healthcare costs. 2, 5
Why Other Options Are Less Common
While the other listed complications do occur with herpes zoster, they are significantly less frequent than PHN:
- Herpes zoster ophthalmicus is a severe but less common manifestation that can lead to blindness 1
- Bacterial superinfections are mentioned as potential complications but occur less frequently than PHN 1
- Unilateral facial paralysis (cranial nerve palsy) is a recognized but uncommon complication 1
- Keratitis would be a subset of ophthalmic involvement, making it even less common than PHN
Prevention Strategy
The most effective strategy to prevent PHN is vaccination against herpes zoster, with two available vaccines: zoster vaccine live (ZVL) and recombinant zoster vaccine (RZV). 1, 4 Early aggressive treatment of acute HZ with antiviral drugs may also reduce the risk of developing PHN. 6, 7