FAQs on Postherpetic Neuralgia from the Top Pain Clinics in Arizona
Shingles (herpes zoster) is a skin rash that usually starts in the middle of the back and wraps around to the chest. However, it can develop anywhere on the body. Shingles gradually disappears over the course of a few weeks or months, but it can reappear. Postherpetic neuralgia (PHN) is a painful condition that often develops in people with shingles.
What causes postherpetic neuralgia?
Many people develop chicken pox as children, but it can occur in older people, too. Chicken pox is caused by the varicella zoster virus, and this virus travels from the skin along the nerves into the dorsal root ganglia, which is a section of the nerve. While the virus remains inactive for many years, it can reappear as shingles years later. With postherpetic neuralgia, the pain continues after the shingles rash has cleared. Reactivation of the virus causes swelling of the nerve and permanent damage, which produces a shingles rash.
What symptoms are associated with PHN?
The pain of shingles is often described as unbearable, horrible, electric-like, sharp, burning, aching, and/or throbbing. In addition, the patient may experience skin sensitivity (allodynia) and itching. With PHN, the pain and associated symptoms continue long after the rash has healed.
Who gets postherpectic neuralgia?
Older people are more at risk for developing shingles, and therefore, having PHN. In addition, older people with some form of neuropathy are more likely to develop postherpetic neuralgia. Some studies have shown that the more severe and painful shingles the rash is, the greater the chance of having long-lasting PHN pain. People with PHN often develop depression, have trouble sleeping, and experience anxiety. Some patients report muscle sagging in the region affected by the shingles. This is caused by damage to the nerves that control muscle tone.
What are the treatments for PHN?
The treatment of postherpetic neuralgia depends on the severity of the pain and associated symptoms. Options include:
- Anticonvulsants – Drugs used to treat seizures can relieve the pain associated with PHN. Neurontin is safe and effective for PHN with few side effects. Lyrica is FDA-approved for the neuropathic pain associated with shingles. Tegretol has been used for years for PHN, but it requires regular blood testing.
- Topical lidocaine patch – This is a smooth, flat patch that affixes to the skin over the painful area. These patches last for approximately 12 hours, and act locally for pain relief.
- Tricyclic antidepressants – Many studies support the use of TCAs for pain associated with PHN. These drugs include nortriptyline (Pamelor), amitriptyline (Elavil), and desipramine (Doxepin).
- Opioid analgesics – When the pain associated with PHN is severe, opioids may be prescribed. Pain management specialists recommend these for short-term use only.
- Sympathetic nerve blocks – Using ultrasound or x-ray guidance, the doctor inserts a needle near the spinal nerves at the affected region. A long-acting anesthetic is injected onto the nerves to block the pain signals. A recent study found that clonidine and bupivacaine were effective block agents for PHN pain, and patients remained pain-free for up to 8 months with this procedure.
- Epidural steroid injection (ESI) – The doctor can inject a corticosteroid agent into the epidural space, which lies between the spinal cord and epidural layer. Research studies show that ESI offers transient pain relief for individuals with PHN.
- Transcutaneous electrical nerve stimulation (TENS) – This small device is worn on the outside of the body. Wires run from the unit to electrodes, which are place along the spine to deliver short electrical impulses for pain signal blockage.
- Radiofrequency ablation (RFA) – For pain relief, the doctor will insert a special needle and probe near the affected nerves. Radiofrequency energy destroys a portion of the nerve root. A recent clinical study showed that RFA provided 12 weeks of pain relief for patients with PHN, and the procedure had an 80% efficacy rate.