Thursday, October 23, 2014

Definition

Article updated and reviewed by Cyrus Badshah, MD PhD, Assistant Professor of Clinical Medicine, College of Physicians and Surgeons, Columbia University; Assitant Attending Physician, Department of Medicine, Division of Infectious Diseases & Medical Director, Chest (TB)Clinic and Directly Observed Therapy Program, Harlem Hospital Center. Editorial review provided by VeriMed Healthcare Network on May 2,2005.

Shingles (or Herpes zoster - zoster for short) is a reactivation of a childhood chicken pox infection during adulthood. However, unlike the rash of chickenpox, which covers large parts of the body, the rash of shingles usually affects a small area of skin on one side of the body, appearing in rows like shingles on a roof.

Description

A typical shingles rash follows the path of certain nerves on one side of the body - generally on the trunk, buttocks, neck, face or scalp - and usually stops abruptly at the midline. Shingles is common in the elderly and rarely seen in younger adults. About two-thirds of all cases occur in persons over the age of 50. It affects both sexes equally.

Although most people suffer only one attack, repeated bouts of the rash occasionally occur, usually at the same site as the first eruption.

Shingles of the face often affect the nose and the eye. When the part of the eye known as the cornea is affected, the condition is known as zoster keratitis. If zoster keratitis is not promptly treated, the condition can scar the cornea, leading to blindness. Therefore, anyone with shingles affecting the upper part of the face should see a physician at once, no matter how mild the condition may seem. A tingling sensation at the tip of the nose may herald possible facial and eye involvement.

Even after the rash disappears, some patients continue to have pain at the site of the rash. When the trigeminal nerve, which supplies the face (including the eyes and the nose), is affected, people are more likely to experience prolonged post-shingles pain.

With advancing age, there is an increased likelihood of the patient being left with an irritating sensation or severe pain at the site of the rash or impairment of vision after the rash of zoster heals.

An attack of shingles generally begins with a fever, generalized discomfort like-chills, headache or an upset stomach and sometimes is accompanied by an itching or burning sensation at the site of the rash. Pain at the site of the rash may precede it by a few days, but is more commonly felt during the attack and/or after the rash disappears.

Very occasionally, shingles pain occurs without a rash. This condition is known as zoster sine herpete. In the absence of a rash, pain in the chest or the back may be so severe as to occasionally be mistaken for a heart attack, a lung infection or spinal problem.

The rash, typically confined to one side of the body, initially appears as a series of raised red spots surrounded by a swollen area. These spots turn into blisters filled with clear fluid, which gradually becomes cloudy. The blisters eventually dry out and crust over. The spots may bleed and become very itchy and painful.

Normally, once the herpetic rash fades, the area stops hurting and there is full recovery. In a few patients, especially those that are immunosuppressed, zoster attacks can be severe with the rash covering a large area of the body. The rash may take three to four weeks to heal.

Causes

Anyone who has had chicken pox has the potential to develop herpes zoster (or shingles) later in life because the same virus that causes chicken pox also causes zoster. The virus remains in a dormant state in certain nerve cells of the body, anywhere from a few months to several years. At some later stage in life, the virus can “reawaken”, causing zoster.

About 20 percent of people who have had chickenpox are affected by zoster at some time in their life. What prompts the virus to "reawaken" and cause problems in normal, healthy people is not clear. Most researchers believe that when the body’s immune response, which normally keeps the virus in check, is temporarily weakened, the shackles on the virus are somehow removed, allowing it to multiply and travel along nerve fibers toward the skin on the surface of the body.

The fact that the disease occurs more often in people over the age of 50 supports this theory, as the immune response is believed to wane with age. Other factors that can also trigger a zoster attack in healthy people include trauma or stress.

A slightly different group of individuals are people who are "immunosuppressed," that is, people whose immune systems are weakened and therefore, are unable to fight off the disease like those with normal, healthy immune systems can. These individuals are more prone to develop zoster and when they do, have a more serious form of it. The grouping of immunosuppressed individuals includes people with leukemia, lymphoma or other forms of cancer, people who have undergone chemotherapy or radiation therapy for cancer, people who have had organ transplants (and are taking drugs that suppress the immune response to prevent the transplanted organs from rejection) and people with diseases that affect the immune system, such as AIDS.

Symptoms

Here's how the disease typically progresses: The earliest indication is feeling very sensitive in a band-like region of the skin on one side of the body (trunk, head, face, neck, or one arm or thigh). Soon that sensitivity is often followed by an intense discomfort, which can be a burning, itching, stabbing or other painful sensation because shingles involves nerve fibers. The pain may be felt from front to back, especially in the chest or face, and is usually felt on just one side of the body. At this early stage, in the absence of a rash, these symptoms can be confusing for both patients and doctors alike, so that the disease may be mistaken for the pain of an ulcer, heart attack, migraineheadache, appendicitis or some other internal disorder, or a lower back problem.

Before the shingles rash appears, one may have a slight fever and feel mildly fatigued. After about four or five days, reddish bumps appear in the painful area. A day or two later, that rash turns into what is the unmistakable hallmark of shingles: groups of tiny, clear blister on a red base. Over the following two or three weeks, the blister fluid first turn brownish, the blisters then dry out, forming crusts which drop off, sometimes leaving behind small pigmented areas where the rash had occurred.

The trunk, neck and back are the most common areas where the rash appears, but in some cases, the eye, the face and the tip of the nose are affected. If this happens, you should see your doctor immediately so that medication can be prescribed to help prevent the blisters from worsening and causing complications like blindness.

Treatment

Onset

The skin of patients with affected by herpes zoster is highly inflamed and tender. The slightest touch can be very painful. In the acute phase of illness, some of the treatment measures are aimed at providing relief from the local discomfort as one would treat an acute attack of sunburn. Such local treatment - where the goal is to sooth sensitive areas of the skin and to prevent clothes from rubbing against painful skin lesions - can consist of wet dressings or compresses with aluminum acetate (also known as Burow's solution - Domeboro). Alternately, topical agents like calamine-containing lotions and creams, 10 percent trolamine salicylate (Aspercreme), and silver sulfadiazine (Silvadene Cream) can be used to achieve the same results.

Besides local relief measures, medications directed against the virus known as antivirals are used in an attack of shingles. Three antiviral drugs have been shown to be effective for this purpose: acyclovir (Zovirax), famciclovir (Famvir) and valacyclovir (Valtrex).

Currently, acyclovir (Zovirax), which is taken orally, is the antiviral agent most commonly used in treating shingles. Acylovir helps to reduce inflammation and pain during an acute attack. It is also effective in reducing the likelihood of long-term pain after the attack, especially in patients aged 55 and older.

Treatment with famciclovir (Famvir) may significantly reduce pain and hasten recovery from an acute attack. Researchers believe that the drug works by preventing the multiplication of the virus during an acute attack which can damage the affected nerves causing pain.

Valacyclovir (Valtrex) is comparable to acyclovir in treating an acute attack of shingles. It is also taken orally, is absorbed better than acyclovir and is likely to resolve pain more rapidly.

Post-shingles Pain (Postherpetic neuralgia)

After an attack of shingles, pain, often intense, (known as postherpetic neuralgia) can persist anywhere from months to more than a year. As attacks of shingles are more commonly seen in older people, the likelihood of postherpetic neuralgia also increases with age.

The culprit causing the pain appears to be a chain of amino acids, known as substance P, which is normally released by nerve fibers when they are damaged. The pain after shingles presumably results from persisting damage to nerves which then continuously leak substance P.

Of the many treatment options available for postherpetic neuralgia, none is reliably effective. The first line of treatment usually consists of using topical formulations containing nonsteroidal anti-inflammatory drugs, such as aspirin or indomethacin, or local anaesthetic agents such as lidocaine used either alone or in combination with prilocaine. Another approach is to combine the antiseizure drug, carbamazepine (Tegretol), with the antidepressant drug, amitriptyline (Elavil). This combination presumably works by suppressing either the release of substance P or the response to it. Injecting local anesthetics to block nerve transmission in the affected nerves can be helpful, but is an elaborate and expensive procedure.

Another treatment option is rubbing a cream containing a substance called capsaicin (Zostrix, Zostrix-HP) over the painful area of skin. Capsaicin itself can produce an intense stinging sensation because it stimulates nerve endings to release substance P. However, if exposure to capsaicin is sustained by causing continuous release of substance P, capsaicin depletes the stores of substance P from the nerves, preventing further release.

More pain-relieving options, which are currently controversial, are the use of injections of steroids and the use of acupuncture or the related technique, TENS (Transcutaneous Electrical Nerve Stimulation - a method of pain relief achieved by the application of minute electrical impulses to nerve endings that lie under the skin).

While there may be considerable overlap between the two, it is important to distinguish between the relief of early pain accompanying shingles from the prevention of the later pain of postherpetic neuralgia. The current lack of treatment options with predictable results for postherpetic neuralgia has prompted researchers to focus on its prevention. Studies evaluating the use of corticosteroids, such as triamcinolone (Mycolog-II, Myco-Triacet II, Mytrex), prednisolone (Pedipred) and prednisone (Deltasone, Orasone) for this purpose are underway.

Questions

Do any diagnostic tests need to be done?

Will any medications be prescribed? If so, what are their side effects?

Are there any signs or symptoms that the doctor should be notified of immediately?

What treatment is recommended for herpes zoster affecting the face or the eyes?

What are the chances that this attack may leave me with any kind of permanent damage?

What can be done to prevent irreversible nerve damage?

Can vitamins help boost the immune system and help prevent damage to the nerve endings?

What will you prescribe for relieving pain or local discomfort?

Does calamine lotion help reduce itching? Are there any home remedies or measures to decrease the discomfort?

Does a pain specialist need to be consulted?

Is zoster contagious? What measures, if any, should be taken to prevent it from spreading to other people?

Can zoster spread to other parts of the body? If so, can anything be done to prevent this from happening?