From the Guidelines
Post-herpetic neuralgia (PHN) can persist for months to years after the initial shingles outbreak, with most cases resolving within 1-3 months but some lasting more than a year. The duration of PHN is a significant concern, as it can impact the patient's quality of life. According to the 2017 HIVMA of IDSA clinical practice guideline for the management of chronic pain in patients living with HIV 1, PHN is distinct from painful distal symmetrical peripheral neuropathies associated with HIV. Key points to consider when managing PHN include:
- PHN is defined as pain that continues for at least 90 days after the onset of the shingles rash
- The risk of developing long-lasting PHN increases with age, with individuals over 60 being at highest risk
- Treatment options include topical agents, oral medications, and interventional procedures for severe cases
- Early aggressive treatment of the initial shingles outbreak with antiviral medications can reduce the risk and severity of PHN. It is essential to note that the evidence provided does not directly address the duration of PHN, but it discusses the management of chronic pain in patients living with HIV, including those with PHN 1. In terms of treatment, the guideline suggests that analgesic efficacy can be achieved with tricyclic antidepressants, certain opioids, gabapentin, tramadol, and pregabalin, among other options 1. However, the primary concern is the duration of PHN and its impact on the patient's quality of life, which can be managed with appropriate treatment and care.
From the FDA Drug Label
The efficacy of pregabalin for the management of postherpetic neuralgia was established in three double-blind, placebo-controlled, multicenter studies These studies enrolled patients with neuralgia persisting for at least 3 months following healing of herpes zoster rash The FDA drug label does not answer the question.
From the Research
Definition and Duration of Postherpetic Neuralgia (PHN)
- Postherpetic neuralgia (PHN) is defined as pain that persists 1 to 3 months following the rash of herpes zoster (HZ) 2, or pain persisting, or recurring, at the site of shingles at least three months after the onset of the acute rash 3.
- PHN is a chronic neuropathic pain condition that persists 3 months or more following an outbreak of shingles 4.
- Patients develop persistent pain classified as PHN 120 days following rash onset 5.
- PHN presents as intense neuropathic pain that can persist for 90 days or longer after the initial onset of symptoms 6.
Risk Factors and Prevalence
- Risk factors for PHN include increasing age, a prodrome of pain before rash onset, the degree of spread of the rash, and severity of pain during the acute attack 5.
- PHN affects about 50% of patients over 60 years of age and 15% of all HZ patients 2.
- At least half of shingles sufferers over the age of 65 years develop postherpetic neuralgia 3.
- Forty per cent of patients over 50 and 75% of those over 75 develop PHN following resolution of the rash 5.
Treatment and Management
- Effective treatment of acute shingles by systemic antivirals at the appropriate time may have some effect in reducing the incidence of PHN 3.
- Pre-emptive treatment with low-dose tricyclics from the time of diagnosis of acute shingles reduces the incidence of PHN by about 50% 3.
- Established PHN should be vigorously treated with adrenergically active tricyclics, and positive relaxation should also be used 3.
- The pharmacological treatment of PHN may include a variety of medications, including alpha-2 delta ligands, other anticonvulsants, tricyclic antidepressants, topical analgesics, tramadol, or other opioids 4.
- Transcutaneous electrical nerve stimulation (TENS) is a minimally invasive, non-pharmacological electrical nerve stimulation device currently approved for the treatment of neuropathic pain in adults, providing patients with an alternative or adjunct treatment option to medication 6.