Shingles is the common name for the disease that results from reactivation of the virus that causes chicken pox within spinal nerves called dorsal root ganglia. The Centers for Disease Control and Prevention estimate that one million people in the United States develop the disease each year. Symptoms include a mild flu-like illness; a unique, one-sided blistering rash and pain. Since most reactivations affect the spinal nerves that supply the back and trunk, back pain with shingles is a common complaint.
Onset
Back pain with shingles sometimes begins three to five days before the rash erupts, according to National Institutes of Health dermatologist Stephen E. Straus in the 2008 edition of "Fitzpatrick's Dermatology in General Medicine." This pre-eruptive back pain is more common in people with immune system problems and those over 60, says Straus. In the absence of the rash, Straus cautions, pre-eruptive back pain can be confused with heart or lung problems, ulcers of the small intestine, liver or kidney stones or intervertebral disk disease.
Duration
Back pain with uncomplicated shingles lasts about 30 days, according to the CDC. However, the CDC cautions that between 8 percent and 70 percent of patients develop a complication called post-herpetic neuralgia, in which the pain pathways of the affected nerve become sensitized and continue to fire even after the inflammation has resolved. The risk of this complication increases with age and, for some people, the pain never subsides.
Location
Shingles pain usually localizes to a single spinal nerve, although sometimes more than one spinal nerve is involved, particularly in people with immune system problems. A doctor can often identify the specific nerve by comparing the location of the skin rash to a special map called a dermatome that identifies the skin areas supplied by individual spinal nerves. According to Whitely, most cases involve the T3 through L3 spinal nerves, which supply the skin and muscles of the back.
Characteristics
Back pain with shingles varies from superficial itching, tingling, or burning to severe, deep, penetrating, electric pain, says Straus. Pain may be constant or episodic. Triggers can include breeze or the faint brush of clothing. For a small number of patients, notes University of Alabama Medical School Professor of Infectious Disease Richard J. Whitely in the 2008 edition of "Harrison's Principles of Internal Medicine," the predominant symptoms are severe itching and numbness. These patients must be counseled to refrain from scratching, because since the skin is numb and patients can't easily reach their own backs, they can unwittingly cause severe tissue damage.
Associated Symptoms
Back pain with shingles is often associated with decreased physical functioning, emotional distress, and decreased social functioning during the acute phase of the disease and beyond for those who develop post-herpetic neuralgia, Common complaints, according to the National Institute of Neurological Disorders and Stroke, or NINDS, include unintentional weight loss, sleeplessness, lethargy, mood changes, antisocial behavior and severe depression. In some cases, notes NINDS, shingles pain can cause a person to become disabled.
Treatment
Prompt initiation of antiviral drugs such as valacyclovir, acyclovir and famciclovir can decrease the severity and duration of the acute episode of shingles, as well as decrease the risk of developing post-herpetic neuralgia, says Whitely. Some doctors may also prescribe a tapered course of oral steroids to quell inflammation within the nerve, and narcotics, such as morphine or fentanil, to control pain. In the case of back pain due to post-herpetic neuralgia, patients typically transition to antidepressants or anticonvulsants and topical local anesthetics, in addition to narcotics.
References
- Centers for Disease Control and Prevention: Herpes Zoster Disease: Q and A's for Providers
- "Harrison's Principles of Internal Medicine, 23rd Edition;" A.S. Fauci et al.; 2008
- "Fitzpatrick's Dermatology in General Medicine, 7th Edition;" K. Wolff et al.; 2008
- National Institute of Neurologial Disorders and Stroke: Shingles: Hope Through Research
- MayoClinic.com: Shingles
