Postherpetic neuralgia (PN) is a chronic complication of herpes zoster (shingles), which affects the nerves. Herpes zoster results from reactivation of dormant viruses in the sensory ganglion and is manifested by acute, painful vesicular rash over a single dermatome (nerve region). The varicella-zoster virus (VZV) is a nerve virus that gains access to neurons during a childhood infection of chickenpox (varicella). More than 95% of young adults are seropositive for VZV, and the incidence rate is 3.4 cases per 1,000 persons.
Patients often have chest wall pain before an outbreak of shingles. With this condition, patients have itching, numbness, and a rash. Once the rash dries up, the pain may continue. The pain can be spontaneous (burning and ongoing), paroxysmal shooting or electric shock-like pain, or the patient may experience evoked sensations in response to light touch or other mechanical stimuli. The type and intensity of pain vary from patient-to-patient.
Postherpetic neuralgia also affects the quality of life and sleep. Patients often report a much pain and suffering due to the condition, which can lead to loss of sleep. Functional status is also affected by the pain, with a limited range of movement of the chest region due to the discomfort.
Duration of Postherpetic Neuralgia
So how long does postherpetic neuralgia last? Researchers are unsure what triggers the herpes zoster virus to re-emerge after years of lying dormant. The virus may be obtained during youth but it will not flare into shingles until years down the line. The pain of shingles usually persists for around three months. When this pain lingers long after the rash heals, it is considered PN.
The bout of shingles damaged the nerves. This means that the nerve damage caused by shingles brings on a fully functioning nervous system. The damaged nerve will send random pain signals to the brain, and it causes a burning, throbbing sensation. Over time, the nerves of the skin calm, but with the nerve damage existing, the pain can persist for years, even for the remainder of a person’s lifetime.
Postherpetic Neuralgia Treatment
- There is currently no disease-modifying therapy for PN. Treatment is based mainly on symptom control. Because pain may persist for years, or for the remainder of life, medication is often used over prolonged periods. Randomized controlled trials support the use of topical and oral agents to treat PN.
• Topical treatment – Topical therapy is the first-line treatment for mild pain. It is used in combination with systemic drugs when pain is moderate or severe. The patches have 5% lidocaine, which is an analgesic agent. In a meta-analysis of studies, this treatment offered patients at least 50% pain relief. Capsaicin cream also has proven effective. It must be applied several times daily and is proven effective as a low-concentration patch.
• Systemic treatment – Certain drugs are used for nerve-related pain. For PN, drugs proven effective are tricyclic antidepressants and antiepileptics. In many studies, amitriptyline, nortriptyline, and desipramine were shown to help treat. Gabapentin and pregabalin are two anticonvulsants that appear to offer some benefit in the treatment of postherpetic neuralgia.