The Pain from Shingles
Dreadful. Horrific. Agonizing. These are some of the adjectives employed to describe the pain from shingles. Ask anyone who's had it and you're likely to hear something like "it was the worst pain I've ever experienced in my life". Almost one million new cases will be diagnosed this year alone, mostly in people age fifty or older. One out of five people will get it in their lifetime, but Caucasians are two to four times as likely to develop shingles compared to African Americans.
The virus that causes the infection, Herpes Zoster, is the same one that causes chickenpox. In fact, only people who have had chickenpox can develop shingles. Once an episode of chickenpox is over, some of the viruses remain in the body, "asleep" in certain areas of the nervous system. The immune system can keep the infection from coming back for many years, but as a person ages, that immunity decreases and the virus reawakens, this time as a nerve and skin infection. Many illnesses, including cancer, can predispose one to shingles.
The areas most commonly affected are the chest/abdomen and the face, mainly the forehead. The pain may precede the typical skin eruption for several days and it is not uncommon for a person to misinterpret the pain as coming from a heart attack or from the gallbladder. Small water-filled blisters appear, along with a rash that typically follows the path of the nerve, radiating, for example, from the spine and traveling to the front of the abdomen, rarely crossing the midline. In severe cases, bleeding and scabbing occurs, and later white patchy scars develop.
The attack may persist for days or weeks, but the episode may be shortened and reduced in intensity if anti viral medication, such as Acyclovir or Famvir, are promptly used. During the attack the pain also follows the path of the nerve and it is usually described as burning, lancinating, shock-like. Strong analgesics, including morphine, may be required for the treatment of pain. Sleep is made most difficult and exhaustion is not uncommon.
As severe as shingles pain is, it is usually gone within a few weeks. While younger people tend to heal completely, older folks have an increased likelihood of developing post herpetic neuralgia (PNH), a persisting pain in the affected area, even after the virus disappears. Statistics vary, but at least one out of ten people who develop shingles will have some degree of pain one year later, and the older the person, the higher the chances of PHN. It appears that the damaged nerve and the spinal cord attached to it become a "pain generator" due to misfiring and hypersensitivity of the nerve cells.
PHN can be very difficult to treat. Many drugs have been tried but few have been found effective, such as amitriptyline, an antidepressant, and Lyrica (pregabalin), a drug used for the treatment of seizures and also approved for use in PHN. Opiate analgesics and sleeping pills are often added for comfort. Local treatments with anesthetic ointments or patches (Lidoderm) can be helpful, while capsaicin cream (made from chili peppers) is poorly tolerated due to the initial burning sensation it causes. Nerve blocks consisting on the injection of local anesthetics and cortisone around the nerves can be very helpful in selected patients. Severe cases may, however, not respond at all and physicians have, in the past, even resorted to cutting the damaged nerves, mostly with poor results.
Instead of waiting and guessing which patients will develop PHN, a current concept in the prevention of PHN relies on "pre-emptive analgesia". That is, treating shingles from the very early stages in such a way as to keep the neuralgia from developing. Instead of saving blocks and anti-neuralgic medications for later, its early use may decrease the chances of PHN.
The widespread use of chickenpox vaccine in children may decrease or eliminate the chances for these children to get shingles in the future, and it is possible that the new modified chickenpox vaccine for adults may confer additional immunity for other folks, preventing shingles altogether.
© Dr. Moacir Schnapp and Dr. Kit Mays
Tell Me Where It Hurts
Pain As A Neurodegenerative Disorder
The Multidisciplinary Approach to Pain
Pain is Obligatory, But Suffering is Optional
Pain: Myth Busters
Sleepless in Pain
The Pain from Shingles
When You Need a Pain Specialist
Why Does Pain Hurt?