"I feel like someone is putting a hot poker in my skin."
"I feel like hundreds of knives are digging and pulsing into my skin."
"I would cut off my thigh if it would make the pain stop."
"I feel like electric shocks are going all the way down my leg."
"It's very embarrassing, but I haven't been able to wear underwear for months."
These are some of the comments from my patients with postherpetic neuralgia, persistent pain that arises from an infection called shingles.
What is Shingles?
Shingles is an acute infection caused by a familiar childhood foe, the varicella-zoster virus that causes chickenpox. Once you've had chickenpox, the virus remains in your body, lying dormant deep within nerve fibers. But the virus can be reactivated, causing the painful rash and blistering that marks shingles. We don't know exactly what reactivates the varicella-zoster virus, but illness, trauma, extreme fatigue or stress may be involved.
During round one with varicella-zoster, the entire body is affected with fever and the small lesions we call chickenpox. In round two, with shingles, only specific nerves are involved, so the symptoms are limited to certain sections of the body. Often, the first symptom is severe pain in a narrow band of the body such as the chest, groin, face, one eye or the outer side of one leg. This may be accompanied by nausea, vomiting and general illness. After a few days, a linear, raised rash will develop — the classic shingles rash.
Making the Diagnosis
Because the pain from shingles starts before the rash appears, the diagnosis can be very difficult to make. I had a patient who developed severe pain in the left side of his chest and was taken to the hospital to rule out a heart attack. The rash erupted two days later. Another patient experienced excruciating burning in her vagina for two days, which worsened when walking, before developing a rash on her abdomen and back.
The main way to identify shingles is to look at how the rash is distributed. Typically, the rash does not cross the midline of the body, only affecting one side of the face, chest or back. The rash consists of fluid-filled blisters or pustules, which may crop up in one cluster or in patches on the skin. Still, although there are distinguishing features to the shingles rash, it can be easily confused with other types of skin inflammation.
Another unfortunately common sign of shingles is ophthalmic zoster, painful lesions that affect the eye and can impair vision. When shingles affects the ear, it is called Ramsay-Hunt syndrome and can cause facial paralysis, hearing loss and vertigo. When the diagnosis is not quite clear, a doctor can take a swab of a fresh lesion and send it to a lab for specialized testing.
Health
How Did I Get It? Can I Give It to Someone Else?
Only people who've had chickenpox can get shingles. On the other hand, being around someone with shingles is a risk only for people who've never been exposed to chickenpox; if they contract the varicella-zoster virus, they'll develop chickenpox, not shingles. This poses a particular concern for pregnant women; chickenpox early in pregnancy raises the risk of birth defects, while a late-term infection increases the risk of delivering a severely ill infant.
Though shingles is seen most often in older people, it can occur at any age, and 10 to 20 percent of people will develop shingles during their lifetime. Up to 50 percent of people age 80 or older can expect to have at least one episode of shingles.
What Causes Shingles Pain?
Pain is the greatest problem with shingles. Postherpetic neuralgia, or PHN, is the term used to describe the pain after the rash has faded. PHN may develop days, weeks or even months after the rash heals. People with PHN suffer from three types of pain:
- constant aching or burning
- lancinating pain (cutting or stabbing feeling)
- allodynia (heightened sensitivity to very minimal stimuli such as a light breeze)
This pain can be accompanied by loss of sensation in the affected area. Most patients report an increase in pain after exposure to cold, but not to heat. Some report numbness or tingling.
The exact cause of the pain associated with shingles is not yet understood. It is most likely caused by a number of factors, including direct nerve injury from inflammation and perhaps hemorrhaging that occurred during the reactivation of the virus. Nerve fibers may be "turned up" to give a constant message of pain that cannot be turned off. There also appears to be abnormal central nervous system processing of the pain signal.
How Long Will It Last?
Skin lesions associated with shingles slowly crust, scab and usually heal within two weeks. New lesions can continue to develop for up to six weeks after the initial outbreak, but usually clear up after two to three weeks. Postherpetic neuralgia is defined as pain lasting for three months or more after the reactivation of the virus. PHN is unusual in young people but is quite common among people older than 60. Though the pain from PHN can be lifelong, in most cases, it lasts only a few months.
Treatment
The key to the treatment of shingles is to make the diagnosis early. This is difficult because the severe pain may come before the rash by a few days.
Oral antiviral drugs
Acyclovir, famciclovir and valacyclovir are oral antiviral drugs that are used in the first 48 to 72 hours of the onset the skin rash. Treatment can reduce the period of viral shedding, and accelerate the rate of healing. These drugs may also shorten the duration of pain from the acute attack. Famciclovir and valacyclovir have easier dosing schedules. They are taken three times a day for 10 days. Acyclovir is dosed five times a day for seven days. None of these medications, however, prevent the development of PHN, although there is some evidence that using them early may shorten the duration of the pain.
Systemic corticosteroids
The use of systemic corticosteroids (such as prednisone) is controversial. Corticosteroids, which ease inflammation, may slightly improve quality of life in the month following a shingles outbreak, but have not been shown to cut the risk of postherpetic neuralgia. They may also cause some nausea and swelling, and increase blood-sugar levels.
Topical steroids
Some of my patients have found the use of topical corticosteroids to be helpful. Fluocinolone acetonide 0.025 percent ointment (not the cream or lotion) can provide some soothing relief, as can EMLA cream or lidocaine HCL 2 percent gel.
Capsaicin
Although capsaicin cream 0.025 percent (the same ingredient found in hot peppers) has been recommended, I don't believe it is helpful. It is applied three to four times daily to the affected area, but can cause a severe burning reaction. This may last for days before a possible numbing effect. If you use this cream, you must be careful to wash your hands afterward.
Narcotic pain medications
Narcotic pain medications (such as morphine or codeine) are sometimes used for managing the initial pain of shingles. Using narcotics for PHN is somewhat controversial, but some people may benefit from the drugs. Possible side effects include confusion, dizziness and constipation, with elderly patients being particularly at risk.
Tricyclic antidepressants
Low-dose tricyclic antidepressants may also be useful. Amitriptyline, nortriptyline and desipramine can be started as soon as a diagnosis is made and can be maintained for three months. Low doses are used for the management of pain. Studies have shown that this treatment may reduce the chance of developing postherpetic pain. Unfortunately, the side effects of these drugs make them unsafe for many elderly patients.
When the Pain Persists
When the pain persists for more than three months the following therapeutic options may be tried:
Gabapentin
Originally introduced as an anti-seizure drug, gabapentin has been shown to be very effective in nerve-related pain, particularly PHN. Since it can be sedating, I often start at a low dose of 100 milligrams every eight hours, rather than the recommended dose of 300 milligrams every eight hours. In my practice, gabapentin has made a dramatic difference in patients' quality of life. Unfortunately, it is quite expensive, and some insurance plans may not cover it for this use.
Lidocaine patch
Another therapy, the lidocaine patch, made up of 5 percent lidocaine, is applied to the most painful areas of the rash. The patch can be used for up to 12 hours in a 24-hour period. This can be very effective, especially for particularly painful days, as it works quickly. However, removal of the patch may aggravate the pain.
When nothing seems to work
For extremely resistant cases of PHN, a referral to a pain specialist may be needed. Nerve blocks, in which anesthetic medication is infused directly into an affected nerve, offer yet another treatment option. When all else fails, surgery to sever the nerve may be recommended.
Summary
Postherpetic neuralgia can be excruciating, disabling and difficult to treat. The best hope for shortening the duration of pain after shingles is early diagnosis and treatment with antiviral medications. It is important to visit the doctor when the pain starts, rather than deciding to live with it for a few days. When the pain persists after the lesions have crusted and resolved, newer medications can be very helpful in reducing the pain. We cannot yet predict who will have pain for weeks, months or for a lifetime, but we can do our best to help manage that pain.
