Treating Postherpetic Neuralgia
Postherpetic Neuralgia (PHN) is the most common complication of herpes zoster, or shingles. It is typically defined as any pain that remains after herpes zoster lesions or rashes heal, commonly following a three-month period. Shingles (also known as herpes zoster) is a skin rash that can be extremely painful. It is a viral infection that affects both men and women and is caused by the same virus that causes chicken pox (varicella zoster).
Shingles appear as a rash, patch or line of painful blisters which arise on the skin over a nerve in the shape of a band. This band follows the distribution of a specific nerve where the virus has been living before it spreads to the skin.
Chicken pox usually affects young children, and its symptoms involve itchy blisters all over the body. Once these symptoms go away, the varicella zoster virus stays in the nerves near the spine. It is almost as if the virus “goes to sleep.” It will “wake up,” however, when the body’s immune system is weakened. The virus then grows in the nerves, causing pain. When the virus reaches the skin, it causes the shingles rash.
The nerves affected by shingles can periodically continue to cause severe pain, even once the shingles have cleared. This acute phase lasts until the lesions are healed, often several weeks after the onset of the rash. Postherpetic neuralgia refers to pain that persists after the acute phase of the illness passes. The exact point at which acute herpes becomes postherpetic neuralgia is arbitrary. Some have proposed that PHN starts when the pain lasts more than three months after the acute lesions heal or persists for more than 3 to 6 months from the beginning of the skin eruptions.
Studies show that PHN accounts for 11 to 15 percent of all referrals to pain clinics. Below are several beneficial options for dealing with postherpetic neuralgia.
- Lidocaine skin patches. These are small, bandage-like patches that contain the topical, pain-relieving medication lidocaine. These patches can be customized to fit only the affected area of the skin. You apply the patches, available only by prescription, directly to painful skin to deliver temporary relief.
- Capsaicin skin patch. A high concentration of an extract of chili peppers (capsaicin) is available as a skin patch to relieve pain. Available only in your doctor’s office, the patch is applied by trained personnel after using a numbing medication on the affected area. The process takes at least two hours, but a single application is effective in decreasing pain in some patients for up to three months. The application can be repeated every three months.
- Omega-3 fatty acids. These good fats, found in cold-water fish (like salmon and mackerel) and fish oil supplements, help decrease inflammation. Non-fish sources include leafy greens, like spinach and purslane, and omega-3 enriched foods like eggs, milk and soy milk.
- Anticonvulsants. Certain anti-seizure medications, including gabapentin (and pregabalin), can lessen the pain of postherpetic neuralgia. These medications can stabilize abnormal electrical activity in your nervous system caused by injured nerves.
- Antidepressants. Antidepressants, such as nortriptyline, duloxetine and venlafaxine, affect key brain chemicals that play a role in both depression and how your body interprets pain. Doctors often prescribe antidepressants for postherpetic neuralgia in smaller doses than they do for depression alone.
- Opioid painkillers. Your doctor may prescribe pain medications containing tramadol, oxycodone or morphine. There is a risk of dependency and addiction when it comes to opioids, so discuss this at length with your doctor.
- Steroid injections. Sometimes, your physician may opt to inject steroids into the spine for postherpetic neuralgia. This is handled during an office visit and usually only takes a few minutes to complete.
At University Pain Medicine Center, we take great care in determining which treatment option is best for reducing and eliminating your pain.
Remember when you are speaking with your physician to include all of your symptoms, any major stresses, recent life changes and family medical history. This will aid in the promptest customization of your treatment plan. In most cases, no specific laboratory tests are required and it commonly takes a combination of treatments to reduce the pain. Feel free to ask questions during your doctor’s appointment and take a family member or friend along, when possible.