Shingles is a viral infection of a nerve that affects the skin surface supplied by that nerve. Caused by the varicella zoster virus (VZV), which is the same virus that causes chickenpox, shingles is more common among older adults.
How common is shingles?
According to the National Institutes of Health (NIH), around 1 million cases of shingles are diagnosed each year in the United States. Around 1 out of every 3 people will develop shingles during their lifetime. Over half of all shingles cases occur in persons age 60 years and older, and the rate of prevalence increases for people over age 70 years.
What are the symptoms of shingles?
Shingles causes a blistering, painful skin rash that last around 2-4 weeks. After the rash goes away, some patients continue to have nerve pain for months. This is known as postherpetic neuralgia (PHN), which is a complication of shingles more common among older adults. Other symptoms of shingles include fever, headache, body aches, and nausea.
The pain associated with shingles may be mild, moderate, or severe, and it is often characterized by shooting, stabbing, burning, and/or itching. The pain only affects one side of the body, as does the rash. Shingles pain may persist for weeks to months after the rash dissipates. If the rash affects the facial nerve, symptoms may include loss of eye motion, drooping eyelid, difficulty moving facial muscles, hearing loss, and problems with taste.
What causes shingles?
Varicella virus is one of the herpes viruses that hide in the nervous system after an outbreak of chickenpox. Nerves connect the central nervous system (CNS) to the rest of the body, and in the right conditions, the herpes zoster virus travels down the nerve cell fibers to renew an active infection and rash. The rash is isolated to one or two bands called dermatomes, usually on the side of the trunk at the waist. Another common area is the face.
What are the risk factors for shingles?
Certain factors and conditions are known to trigger an outbreak of shingles. Risk factors include:
- Aging – Shingles is 10 times more likely to affect someone age 60 years and older.
- Certain diseases – These include leukemia, lymphoma, cancer, and HIV/AIDS. People with HIV are 25 times more likely to have shingles than the rest of the general population.
- Cancer treatments – Radiation therapy and chemotherapy lower the body’s immune defense system and increase chances for shingles.
- Stress or trauma – This includes emotional and psychological stressors.
- Medications – Immunosuppressive drugs and steroids can affect the body’s defense system.
How is shingles diagnosed?
Shingles is diagnosed based on the symptoms and distinctive appearance of the rash along a particular dermatome (skin region associated with a nerve root). Laboratory and diagnostic testing is not used to diagnose shingles, but the doctor may test the blister fluid for antibodies to the varicella zoster virus.
How is shingles treated?
There is no way to eliminate the varicella virus from the body, but treatment is aimed at alleviating symptoms and preventing PHN. Options are:
- Home care – Keep the rash clean and dry, wear loose-fitting clothing, do not cover the rash with a dressing, use calamine lotion to soothe pain and itching, and take a mild Benadryl preparation for relief.
- Medications – The doctor can prescribe topical anesthetics, such as lidocaine to ease pain. Other drugs used for nerve-related pain include tricyclic antidepressants (amitriptyline and nortriptyline, anticonvulsants (Neurontin and Tegretol), and opioid pain relievers (codeine and hydrocodone). The doctor may prescribe 7-10 days of an antiviral agent to reduce shingles duration and severity, as well as decrease the risk for PHN. Options are Zovirax and Valtrex.
- Selective nerve root block – The doctor can inject the affected nerve root with an anesthetic or neurolytic agent, or he can use radiofrequency energy to destroy a portion of the nerve. This procedure involves use of fluoroscopy (x-ray guidance) to assure correct needle/probe placement. According to a recent research report, nerve block has an 87% efficacy rate.
Narouze SN, Vydyanathan A, Kapural L, et al. (2009). Ultrasound-guided cervical selective nerve root block: A fluoroscopy-controlled feasibility study. Reg Anesth Pain Med, 34(4):343-348.