Post Herpetic Neuralgia
What is Post Herpetic Neuralgia?
Post herpetic neuralgia is the most common complication of shingles. The condition affects nerve fibers and skin, causing burning pain that lasts long after the rash and blisters of shingles disappear. The chickenpox (herpes zoster) virus causes shingles. The risk of postherpetic neuralgia increases with age, primarily affecting people older than 60. There’s no cure, but treatments can ease symptoms. For most people, postherpetic neuralgia improves over time.
What Are The Symptoms?
The signs and symptoms of postherpetic neuralgia are generally limited to the area of your skin where the shingles outbreak first occurred — most commonly in a band around your trunk, usually on one side of your body.
Signs and symptoms might include:
- Pain that lasts three months or longer after the shingles rash has healed. The associated pain has been described as burning, sharp and jabbing, or deep and aching.
- Sensitivity to light touch. People with the condition often can’t bear even the touch of clothing on the affected skin (allodynia).
- Itching and numbness. Less commonly, postherpetic neuralgia can produce an itchy feeling or numbness.
What Are The Causes?
Once you’ve had chickenpox, the virus remains in your body for the rest of your life. As you age or if your immune system is suppressed, such as from medications or chemotherapy, the virus can reactivate, causing shingles. Postherpetic neuralgia occurs if your nerve fibers are damaged during an outbreak of shingles. Damaged fibers can’t send messages from your skin to your brain as they normally do. Instead, the messages become confused and exaggerated, causing chronic, often excruciating pain that can last months — or even years.
When you have shingles, you might be at greater risk of developing postherpetic neuralgia as a result of:
- Age. You’re older than 50.
- Severity of shingles. You had a severe rash and severe pain.
- Other illness. You have a chronic disease, such as diabetes.
- Shingles location. You had shingles on your face or torso.
- Your shingles antiviral treatment was delayed for more than 72 hours after your rash appeared.
What Are The Treatments?
No single treatment relieves postherpetic neuralgia for everyone. It often takes a combination of treatments to reduce the pain.
Lidocaine skin patches
These are small, bandage-like patches that contain the topical pain-relieving medication lidocaine. These patches can be cut to fit only the affected area. You apply the patches, available by prescription or over-the-counter at a slightly lower dosage, 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 (Qutenza) 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 because you need to be monitored after the high-concentration patch is applied, but a single application decreases pain for some people for up to three months. If it works, the application can be repeated every three months.
Certain anti-seizure medications, including gabapentin (Gralise, Horizant, Neurontin) and pregabalin (Lyrica), can lessen the pain of postherpetic neuralgia. These medications stabilize abnormal electrical activity in your nervous system caused by injured nerves. Side effects include drowsiness, unclear thinking, unsteadiness and swelling in the feet.
Certain antidepressants — such as nortriptyline (Pamelor), amitriptyline, duloxetine (Cymbalta) and venlafaxine (Effexor XR) — 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.
Common side effects of these medications include drowsiness, dry mouth, lightheadedness and weight gain.
Some people might need prescription-strength pain medications containing tramadol (Ultram, Conzip), oxycodone (Percocet, Roxicet) or morphine. Opioids can cause mild dizziness, drowsiness, confusion and constipation. However, recent CDC guidelines urge doctors to consider treatments other than opioids for pain that isn’t cancer-related, such as the pain of postherpetic neuralgia.
Steroids are sometimes injected into the spine (intrathecal or epidural) for postherpetic neuralgia. However, evidence of effectiveness is inconsistent. A low risk of serious side effects, including meningitis, has been associated with their use.