Friday 23 March 2012

Shingles (Herpes zoster)

Shingles

Understanding the nerve distribution along the dermatomes is helpful in determining how certain diseases, such as shingles and some other neurological conditions, target one area of the body. The letter-number combinations show the relationship between each area and its corresponding sensory nerve. The vertebrae are classified as C for cervical, T for thoracic, L for lumbar, and S for sacral. The trigeminal nerve is the fifth cranial nerve, represented by V.
Adult dermatome

Herpes Zoster

Shingles (herpes zoster) is a painful, blistering skin rash due to the varicella-zoster virus, the virus that causes chickenpox. 

Causes, incidence, and risk factors

After you get chickenpox, the virus remains inactive (becomes dormant) in certain nerves in the body. Shingles occurs after the virus becomes active again in these nerves years later.
The reason the virus suddenly become active again is not clear. Often only one attack occurs.
Shingles may develop in any age group, but you are more likely to develop the condition if:
  • You are older than 60
  • You had chickenpox before age 1
  • A classical pattern for shingles. The infection follows a nerve root from the spine, along a rib, to the front of the chest. The area innervated by the nerve is called a "dermatome".
    Herpes zoster (shingles) on the back
    Your immune system is weakened by medications or disease
If an adult or child has direct contact with the shingles rash on someone and has not had chickenpox as a child or a chickenpox vaccine, they can develop chickenpox, rather than shingles.

Symptoms

The first symptom is usually one-sided pain, tingling, or burning. The pain and burning may be severe and is usually present before any rash appears.
Red patches on the skin, followed by small blisters, form in most people.
  • A close-up picture of herpes zoster skin lesions. Four small blisters are shown with redness around them. These vesicles will break, crust over, scab, and finally heal.
    Herpes zoster (shingles) - close-up of lesion
    The blisters break, forming small ulcers that begin to dry and form crusts. The crusts fall off in 2 to 3 weeks. Scarring is rare.
  • The rash usually involves a narrow area from the spine around to the front of the belly area or chest.
  • The rash may involve face, eyes, mouth, and ears.
Additional symptoms may include:
  • Abdominal pain
  • Chills
  • Difficulty moving some of the muscles in the face
  • Drooping eyelid (ptosis)
  • Fever and chills
  • General ill-feeling
  • Genital lesions
  • This is a picture of herpes zoster (shingles) on the arm. Shingles are caused by the same virus that causes chickenpox. Outbreaks of shingles follow the distribution of nerves in the skin. This distribution pattern, seen here on the arm, follows a dermatome (see the "dermatomes" picture).
    Herpes zoster (shingles) on the arm
    Headache
  • Hearing loss
  • Joint pain
  • Loss of eye motion
  • Swollen glands (lymph nodes)
  • Taste problems
  • Vision problems
You may also have pain, muscle weakness, and a rash involving different parts of your face if shingles affects a nerve in your face. 

Signs and tests

Your doctor can make the diagnosis by looking at your skin and asking questions about your medical history.
Tests are rarely needed, but may include taking a skin sample to see if the skin is infected with the virus that causes shingles.
This is a picture of herpes zoster (shingles) on the chest. Shingles are caused by the same virus that causes chickenpox. Outbreaks of shingles often follow the distribution of nerves in the skin. This distribution pattern is called a dermatome (see the "dermatomes" picture). The linear distribution of the nerve in the skin is very easily seen in this photograph.
Herpes zoster (shingles) on the chest
Blood tests may show an increase in white blood cells and antibodies to the chickenpox virus but cannot confirm that the rash is due to shingles.

Treatment

Your doctor may prescribe a medicine that fights the virus, called an antiviral. The drug helps reduce pain and complications and shorten the course of the disease. Acyclovirfamciclovir, and valacyclovir may be used.
The medications should be started within 24 hours of feeling pain or burning, and preferably before the blisters appear. The drugs are usually given in pill form, in doses many times greater than those recommended for herpes simplex or genital herpes. Some people may need to receive the medicine through a vein (by IV).
Shingles, or herpes zoster, is caused by the same virus that causes chickenpox. The virus can lie dormant in the body for many years and re-emerge as shingles. Shingles appear as a painful rash. It consists of red patches of skin with small blisters (vesicles) that look very similar to early chickenpox. Shingles usually clears in 2 to 3 weeks and rarely recurs.
Shingles
Strong anti-inflammatory medicines called corticosteroids, such as prednisone, may be used to reduce swelling and the risk of continued pain. These drugs do not work in all patients.
Other medicines may include:
  • Antihistamines to reduce itching (taken by mouth or applied to the skin)
  • Pain medicines
  • Zostrix, a cream containing capsaicin (an extract of pepper) that may reduce the risk of postherpetic neuralgia
Cool wet compresses can be used to reduce pain. Soothing baths and lotions, such as colloidal oatmeal bath, starch baths, or calamine lotion, may help to relieve itching and discomfort.
This is a picture of herpes zoster (shingles) on the hand and fingers. Shingles are caused by the same virus that causes chickenpox. Outbreaks of shingles often follow the distribution of nerves in the skin. This distribution pattern is called a dermatome (see the "dermatomes" picture).
Herpes zoster (shingles) on the hand and fingers
Resting in bed until the fever goes down is recommended.
The skin should be kept clean, and contaminated items should not be reused. Nondisposable items should be washed in boiling water or otherwise disinfected before reuse. The person may need to be isolated while lesions are oozing to prevent infecting other people who have never had chickenpox -- especially pregnant women.

Expectations (prognosis)

Herpes zoster usually clears in 2 to 3 weeks and rarely recurs. If the virus affects the nerves that control movement (the motor nerves), you may have temporary or permanent weakness or paralysis.
This is a picture of herpes zoster (shingles) on the neck and cheek. Shingles are caused by the same virus that causes chickenpox. Outbreaks of shingles often follow the distribution of nerves in the skin. This distribution pattern is called a dermatome (see the "dermatomes" picture).
Herpes zoster (shingles) on the neck and cheek
Sometimes, the pain in the area where the shingles occurred may last from months to years. See: Postherpetic neuralgia

Complications

Sometimes, the pain in the area where the shingles occurred may last for months or years. This pain is called postherpetic neuralgia. It occurs when the nerves have been damaged after an outbreak of shingles. Pain ranges from mild to very severe pain. It is more likely to occur in people over 60 years.
Other complications may include:
  • Another attack of shingles
  • Blindness (if shingles occurs in the eye)
  • Shingles occurs more commonly on the chest and back, but can involve the arms and legs. The small blisters on this person's hand represent involvement of the dermatome innervated by the 7th cervical nerve. (See the Dermatomes picture.)
    Herpes zoster (shingles) on the hand
    Deafness
  • Infection, including encephalitis or sepsis (blood infection) in persons with weakened immune systems
  • Bacterial skin infections
  • Ramsay Hunt syndrome if shingles affected the nerves in the face

Calling your health care provider

Call your health care provider if you have symptoms of shingles, particularly if you have a weakened immune system or if your symptoms persist or worsen. Shingles that affects the eye may lead to permanent blindness if you do not receive emergency medical care.

Prevention

Avoid touching the rash and blisters of persons with shingles or chickenpox if you have never had chickenpox or the chickenpox vaccine.
Herpes zoster (shingles) normally occurs in a limited area that follows a dermatome (see the "dermatome" picture). In individuals with damaged immune systems, herpes zoster may be widespread (disseminated), causing serious illness. Herpes zoster is caused by the same virus that causes chickenpox.
Herpes zoster (shingles), disseminated
A herpes zoster vaccine is available. It is different than the chickenpox vaccine. Older adults who receive the herpes zoster vaccine are less likely to have complications from shingles. Adults older than 60 should receive the herpes zoster vaccine as part of routine medical care.