Dear Doctor: I’m a 78-year-old woman who developed shingles in December 2014. The rash settled in the nerves on my left side, from under the breast, to the waist and around the middle of my back. Is there anything to ease the pain? Would the shot help?
Shingles is a reactivation of the herpes zoster virus – the virus that causes chicken pox. When people contract chicken pox, usually as children, the virus makes its way along their sensory nerves, ending up at the nerve cells along the spine. The virus then sits within the cells in a dormant state. It can stay there for the rest of a person’s life and not cause problems, with the body’s immune system keeping the virus in a dormant state. However, when immunity decreases, the virus can replicate within a nerve cell, following a particular nerve pathway to the skin and creating a rash along that pathway. The most common risk factor for developing shingles is age, with 80- to 89-year-olds having 10 times greater risk compared with those 10 years and younger.
The nerve pain created by shingles can be very severe and can persist even after all the lesions have disappeared. The pain can be burning, sharp or stabbing and can worsen with even the lightest touch. When the pain lasts for more than four months, the diagnosis is termed post-herpetic neuralgia. That’s the pain syndrome you have.
There are many medications for post-herpetic neuralgia. Tricyclic anti-depressants like amitriptyline, nortriptyline and desipramine work to decrease pain signals from the skin to the central nervous system. However, they’re often not well-tolerated in older patients and can lead to sedation, dry mouth and worsening memory. They would not be my first choice for you.
Gabapentin (Neurontin) and pregalbin (Lyrica) work directly through the nerves to decrease pain. Gabapentin causes much more drowsiness compared to pregalbin. Many of my patients who have difficulty with sleep at night due to the pain of post-herpetic neuralgia do well with Gabapentin. However, people with symptoms that also occur during the day often can’t tolerate the sedating effects of Gabapentin. I switch many of these patients to pregalbin; while pregalbin can cause drowsiness, it is better-tolerated. The anti-seizure drug valproic acid also can significantly decrease pain.
Capsaicin, the active component of chili peppers, is known for irritating the sensory nerves, but perhaps remarkably, can lead to pain relief when used in cream form for those with post-herpetic neuralgia. Note that you have to apply capsaicin multiple times per day, and for many people, the burning, stinging sensation is intolerable.
Opiates also can relieve the acute pain, but when used long-term, can cause tolerance and addiction.
As for the shingles vaccine, although you had shingles more than 2 years ago, the vaccine could still reduce the risk of future episodes. However, no vaccination studies have been done in patients who have already had shingles, so the potential benefit is unclear. In addition, the vaccine won’t reduce your current nerve pain.
In summary, I recommend speaking to your doctor about medications like gabapentin or pregalbin and whether to get the shingles vaccine to perhaps decrease the risk of future episodes.
Robert Ashley, MD, is an internist and assistant professor of medicine at the University of California, Los Angeles.
Ask the Doctors is a syndicated column first published by UExpress syndicate.
