Varicella

Chicken Pox

Clinical Description

The varicella zoster virus (VZV) can cause two diseases: chickenpox (varicella) and shingles (herpes zoster). Before a vaccine was developed in 1994, chickenpox was a common contagious childhood disease that produced itchy blisters but rarely caused serious problems. However, if adults who did not have the disease as children contract it, it could cause more serious complications.

Shingles is caused by the same virus that causes chickenpox. Once you have had chickenpox, the varicella-zoster virus lies dormant in your nerves and can re-emerge as shingles. Shingles, which is characterized by a rash of blisters, can be very painful but is not life-threatening. Some people who develop shingles also develop a condition caused postherpetic neuralgia, which causes the skin to remain painful even after the rash is gone. Shingles is most common in people over age 60 or in those with a weak immune system.

Signs and Symptoms
Chickenpox

The typical rash of chickenpox is made up of groups of small, itchy blisters surrounded by inflamed skin. The rash usually starts on the face, scalp, or chest, quickly spreading throughout the body. It usually appears a few days after the individual has been exposed. Over 4 days, each blister tends to dry out and form a scab, which then falls off 9 - 13 days later.

The rash is usually preceded or accompanied by:

  • Fever, usually low grade
  • Fatigue
  • Headache
  • Flu like symptoms
Shingles

The typical shingles rash starts as redness followed by blisters that usually cover only one side of the body. The rash follows the path of the nerve where the virus has lain dormant. About 50 - 60% of people with shingles have the rash on their trunk. The next most common site is one side of the face, which may even include the tongue, eye, or ear.

Before the rash appears, the infected individual will have warning symptoms of pain -- usually a sharp, aching, piercing, tearing, or burning sensation -- on the part of the body where the rash appears 1 - 5 days later. That area may also feel itchy, numb, and unbearably sensitive to touch, even just from clothes touching the skin.

Other symptoms may include:

  • Fever
  • Malaise (feeling unwell) and other flu like symptoms including muscle aches
  • Headache
  • Swollen lymph nodes
  • Upset stomach

Source: Varicella-zoster virus http://www.umm.edu/altmed/articles/varicella-zoster-000080.htm#ixzz2Ucda5SWz


Diagnosis

A physician can usually diagnose chickenpox easily because of its characteristic rash. If there is any doubt, however, the doctor may view a scraping from one of the blisters under the microscope.

For cases of shingles, a physician can usually make a diagnosis from the history of pain and other symptoms and the rash itself. He or she may take a scraping from one of the blisters for a laboratory test.

Source: Varicella-zoster virus http://www.umm.edu/altmed/articles/varicella-zoster-000080.htm#ixzz2UceMGGEM


Epidemiology

Transmission:
Chickenpox

Both chickenpox and shingles are caused by the varicella-zoster virus (VZV), a type of herpes virus. The virus is spread when you come in contact with the rash or by sneezing, coughing, and breathing -- in other words, when someone with chickenpox sneezes or coughs, there are droplets with the VZV virus in the air. The person is contagious from 2 days before the rash appears until all of the blisters have crusted over.

Shingles

While shingles is caused by the same virus that leads to chickenpox, the way you develop this painful skin condition is different. After you have had chickenpox, the virus lives in a dormant state, as if it is hibernating, in nerve cells along your spine. Later in life, when it "wakes up" -- usually from a weakened immune system, aging, or other risk factor -- the virus travels down the path of the particular nerve where it was "hibernating," causing pain followed by the rash. Anyone who has had chickenpox can get shingles, although a vaccine can reduce your risk.

Risk Factors
Chickenpox
  • Exposure to the virus if you have not had chickenpox nor received the vaccine
  • Being under 10 years of age
  • Time of year: late winter and early spring is the most common time that the virus is spread
Shingles
  • Age (most common in people over 60)
  • Stress
  • Weakened immune system (for example, people with HIV/AIDS, or those taking drugs to suppress the immune system due to autoimmune diseases or organ transplants)
  • Having had chickenpox before age 1

Source: Varicella-zoster virus http://www.umm.edu/altmed/articles/varicella-zoster-000080.htm#ixzz2Uceb7z8g


Prevention and Control

Chickenpox
  • The chickenpox vaccine (Varivax) is given to every child over 1 year old. If a person receives the vaccine before age 13, then he or she only needs one dose. If a person receives the vaccine when he or she is older than 13, a second dose is needed 1 - 2 months later.
  • If you have never had chickenpox or the vaccine, avoid contact with anyone who has chickenpox.
  • Children with chickenpox should be kept out of school or daycare until their doctor says otherwise to avoid spreading the virus.
Shingles
  • If you have never had chickenpox, the chickenpox vaccine can reduce your risk of getting chickenpox and shingles. Even if you do get the disease, having had the vaccine reduces the risk of complications.
  • The shingles vaccine (Zostavax) can reduce the risk of getting shingles among people who are over 60 and have had chickenpox. It doesn't completely ensure you won't get shingles, but if you do, having had the vaccine reduces the severity and the risk of postherpetic neuralgia.
  • The shingles vaccine is not recommended for people who:
    • Have ever had a reaction to gelatin or neomycin
    • Have a weakened immune system
    • Take drugs to suppress the immune system (such as corticosteroids)
    • Have tuberculosis
    • Have a history of lymphatic or bone marrow cancer
  • One study found that older adults who practice tai chi regularly had a better immune response to the varicella virus, and their immunity increased even more when they had the shingles vaccine.

Source: http://www.cdc.gov/rotavirus/clinical.html, http://who.int/mediacentre/news/releases/2009/rotavirus_vaccines_20090605/en/

Common Disease Taxonomy: