The term shingles is derived from the Latin and French words for belt or girdle, reflecting the distribution of the rash in usually a single broad band. This band of pain and infection is only on one side of the body in the large majority of people and represents a dermatome -- the area that a single sensory nerve supplies in the skin. The painful area may occupy part or all of the dermatome and the total distribution is not linear but may blossom at the nerve endings of the dermatone and be a patch of infected nerve endings resulting in blisters. It is rare for shingles to affect more than one dermatone on one side of the body.
Shingles is caused by the varicella-zoster virus , the same virus that causes chickenpox. Anyone who's had chickenpox may develop shingles. After you recover from chickenpox, the virus can enter your nervous
system and lie hidden for years. Eventually, it may reactivate and travel along nerve pathways to your skin producing shingles. Varicella-zoster is part of a group of viruses called herpes viruses, which includes the viruses that cause cold sores and genital herpes. Because of this, shingles is also known as herpes zoster. But the virus that causes chickenpox and shingles is not the same virus responsible for cold sores or genital herpes, a sexually transmitted disease. A person with shingles can pass the varicella-zoster virus to anyone who hasn't had chickenpox. This usually occurs through direct contact with the open sores of the shingles rash. Once infected, the person will develop chickenpox, however, not shingles.
Under certain circumstances, such as emotional stress, immune deficiency (from AIDS or chemotherapy), or with cancer, the virus reactivates and causes shingles. In most cases of shingles, however, a cause for the reactivation of the virus is never found. Anyone who has ever had chickenpox is at risk for the development of shingles. Today there exists a vaccination for those who have had chickenpox that may prevent shingles. Shingles is more common in older adults and in people who have weak immune systems. It has been estimated that up to 1,000,000 cases of shingles occur each year in the U.S.
Treatments for shingles:
There are several effective treatments for shingles. Drugs that fight viruses (antivirals), such as acyclovir (Zovirax), valacyclovir (Valtrex), or famciclovir (Famvir), can reduce the severity and duration of the rash if started early (within 72 hours of the appearance of the rash). In addition to antiviral medications, pain medications may be needed for symptom control. Both nonsteroidal anti-inflammatory medications and narcotic pain control medications may be used for pain management in shingles. The diet may be supplemented with 1000 mgm. doses of L-Lysine and St. John's Wort has proven helpful. Nuts and pineapple should not be in the diet of anyone who has shingles. Tens or interferential therapy can be applied to the affected area, but in most cases the pain from shingles is of short duration and tens therapy or interferential therapy is not indicated, unlike when the shingles pain persists and the patient has postherpetic neuralgia.
The affected area should be kept clean. Bathing is permitted, and the area can be cleansed with soap and water. Cool compresses and anti-itching lotions, such as calamine lotion, may also provide relief. Capsaicin cream (Zostrix), a derivative of hot chili peppers, can be used topically on the area after all the blisters have healed, to reduce the pain. Lidocaine pain patches (Lidoderm) applied directly to the skin can also be helpful in relieving nerve pains by numbing the nerves with local lidocaine anesthetic. These options should be discussed with your health-care professional.
What are shingles symptoms and signs? How long does shingles last?
Before a rash is visible, the patient may notice several days to a week of burning pain and sensitive skin. When the characteristic rash is not yet apparent, it may be difficult to determine the cause of the often severe pain. Shingles rash starts as small blisters on a red base, with new blisters continuing to form for three to five days. The blisters follow the path of individual nerves that come out of the spinal cord in a specific "ray-like" distribution (called a dermatomal pattern) and appear in a band-like pattern on an area of skin. The entire path of the affected nerve may be involved, or there may be areas in the distribution of the nerve with blisters and areas without blisters. Generally, only one nerve level is involved. In a rare case, more than one nerve will be involved. Eventually, the blisters pop, and the area starts to ooze. The affected areas will then crust over and heal. The duration of the outbreak may take three to four weeks from start to finish. On occasion, the pain will be present but the blisters may never appear. This can be a very confusing cause of local pain.
What is postherpetic neuralgia?
The most common complication of shingles is postherpetic neuralgia. This occurs when the nerve pain associated with shingles persists beyond one month, even after the rash is gone. It is a result of irritation of the nerves of sensation by the virus. The pain can be severe and debilitating. Postherpetic neuralgia occurs primarily in people over the age of 50 and affects 10%-15% of people with shingles. There is evidence that treating shingles with antiviral agents can reduce the duration and occurrence of postherpetic neuralgia.
The pain associated with postherpetic neuralgia can be severe and long lasting. Wind, temperature changes, perspiration can all be painful for the patient suffering from postherpetic neuralgia. For postherpetic neuralgia interferential therapy is indicated. Tens therapy can also be used but only after it has been ascertained the carryover pain relief effect of interferenital is not substantial enough to warrant interferential on an as needed basis rather than constant wearing of a tens unit.
Electrode placement for tens and interferential is the same for both. Interferential therapy requires longer, strip type electodes due to the higher current being delivered. Both tens and interferential are at home, as needed treatments that are self administered when possible. The dermatone that was affected by the shingles is the treatment path for electrotherapy. For sake of discussion, on any tens or interferential unit, there are two electrodes per channel, two channels per unit.
Each channel has one electrode that emits electricity and the other electrode is the ground or where the electricity from the first electrode travels to to be absorbed. One electrode sends electricity and the other removes the electricity from the body. This allows the targeting of the electrical stimulus to a specific area, ie. the dermatone.
One electrode, from channel 1, is placed directly beside the origin point where the dermatone exits the spinal chord. The other electrode for channel 1 is placed about 2/3rds of the way down the dermatone. What this accomplishes is from the origin point to 2/3 rds down the affected dermatone there is electrical stimulus.
On channel 2 one electrode is placed between the two electrodes approximately 1/3rd down, and the other electrode from channel 2 is placed at the distal end of the dermatone, or the end of the area where the patient is experiencing pain. This electrode placement now covers the entire dermatone from point of insertion to the farthest point on innervation with an electrical chemical stimulus and also affects the sensory nerve endings to stop or severely reduce the severity of the pain.
With interferential therapy the patient should feel immediate pain relief and have an extended carryover pain relief extending from hours to days, or possibly a week. At the point that carryover, residual pain relief is reaching a week the probability of continued pain should be diminishing completely.