US Pharm. 2015;40(3):13-14.
Chronic Nerve Pain From Shingles
Postherpetic neuralgia (PHN) is a painful nerve condition that lingers after a shingles (herpes zoster) infection. Nerve pain, or neuralgia, is a common symptom of shingles, but in most cases the pain disappears a few weeks after the rash and blisters clear up. Chronic nerve pain occurs in about 20% of patients who develop shingles in their 60s, and it is even more likely in 70- and 80-year-old patients with shingles. Postherpetic neuralgia pain can continue for months or years as a result of nerve damage caused by the shingles virus. Although there is no cure, there are several medications that can be used to ease PHN pain.
Condition Can Be Prevented With the Shingles Vaccine
Shingles (herpes zoster) is a painful condition that can develop many years after a person contracts chickenpox. The virus that causes chickenpox, varicella zoster, quietly remains inactive in the nervous system after a person recovers from chickenpox. In certain patients, the varicella zoster virus becomes active again in later life (usually after age 60 years), causing the pain, rash, and blisters of shingles. People most likely to develop shingles are those with a weak immune system, often from a chronic disease or drug therapy. Common causes of weakened immunity include emotional or physical stress, traumatic injuries, cancer, autoimmune disease, HIV/AIDS, and treatments such as chemotherapy, steroids, and radiation therapy.
Symptoms and Diagnosis
Shingles most commonly causes pain, burning, itching, and skin sensitivity around one side of the chest, neck, or face. The painful area usually develops a rash, which forms blisters that break open, crust over, and heal. For most patients, the pain of shingles slowly disappears over a few weeks once the blisters have healed. In some patients, especially those with shingles on the face, the pain continues for several months after shingles has healed. These patients are suffering from postherpetic neuralgia (PHN), a chronic condition that results from damage to the nerves affected by the shingles virus. PHN is diagnosed after the pain, itching, and skin sensitivity of shingles do not disappear by 4 weeks after a shingles infection has healed. Typically, the virus causes damage to the nerves in the same area of skin as that of the shingles symptoms. The pain can be constant, or it may come and go. Most people with PHN describe the pain as a stabbing pain, an electric or tingling sensation, or an aching pain. It can be mild, but it may be severe enough to interfere with sleep or daily activities. Often people describe the affected skin as extremely sensitive to the touch, even by contact with clothing.
Treatment is aimed at relieving the pain with oral (taken by mouth) and topical (applied on the skin) medications. The drugs used to relieve PHN include anticonvulsants, antidepressants, anti-inflammatories, and pain relievers such as ibuprofen, acetaminophen, or opioids. Numbing drugs such as lidocaine are available as a cream, spray, or skin patch, and counterirritants such as capsaicin cream may also provide temporary relief. If the pain is not relieved by any of these measures, a pain specialist should be consulted.
Herpes Zoster Vaccine
PHN pain can be reduced or prevented by taking oral antiviral medication as soon as possible at the first sign of shingles (pain or rash). The most effective way to prevent PHN, however, is to prevent shingles infection with the herpes zoster vaccine (Zostavax). This injectable vaccine can be given to adults aged 50 years or older. It is recommended for all adults 60 years of age and older, even if they have suffered from shingles in the past. The shingles vaccine is not useful for treating PHN once it has developed.
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