Varicella Zoster Virus
Written by Ada’s Medical Knowledge Team
The varicella zoster virus causes the common condition chickenpox when it infects a person for the first time and, if reactivated later in life, causes the painful skin condition known as shingles.
The varicella zoster virus goes by several names, including:
Varicella zoster is very common, and most people contract it during childhood. Varicella infections are usually not serious, but they can be uncomfortable or even painful. Further, chickenpox and shingles can both pose the risk of complications if they affect pregnant people. However, the prognosis is usually good, except in cases where the affected person has a weak immune system and in otherwise healthy people, the conditions of chickenpox and shingles usually heal without causing any long-term problems.
Good to know: The terminology used to refer to the conditions caused by the varicella zoster virus or HHV-3, can be confusing for non-medical professionals. It may be helpful to keep in mind that the terms varicella zoster or varicella refer to chickenpox, while the term herpes zoster usually refers to shingles.
Chickenpox: varicella zoster
Although chickenpox is a common disease, it is now encountered less often than it was in the past. Many countries routinely vaccinate children against it, often in combination with the vaccines against measles, mumps and rubella.
Nevertheless, chickenpox commonly affects children, with outbreaks most often occurring at kindergartens and elementary schools. It also frequently happens that the siblings, parents or caregivers of a child with chickenpox develop the condition, which is contagious. Adults and teenagers can contract chickenpox, particularly if they have not been vaccinated. Chickenpox can be a serious health problem for pregnant people, the immunosuppressed of any age and sometimes unvaccinated children.
The most distinctive symptom of chickenpox is a blister-like, itchy rash. Other symptoms may include:
- Body aches.
These three symptoms are known as a prodrome, meaning that they indicate a condition is developing, and often appear before the rash develops.
Younger children often find the symptoms of chickenpox quite mild and may only be slightly uncomfortable. Teenagers and adults tend to experience symptoms of chickenpox more severely than children do. Children, adults and teenagers alike should not attend school or work while they have chickenpox, but should stay home until the rash has completely crusted over.
Chickenpox usually resolves within five to ten days. Complications can develop, but these are not common. Potential complications include pneumonia, secondary bacterial infections and, rarely, encephalitis, or inflammation of the brain. The outlook in cases of chickenpox is usually good, and most people recover without any particular treatment.
Shingles: herpes zoster
While chickenpox commonly affects children, shingles is far more common among older adults. The primary symptom of shingles is a painful, blistering rash affecting one side of the face, trunk or a single limb.
After the primary varicella zoster infection, or chickenpox, has resolved, the varicella virus remains in the body for life. It is usually inactive, but it can be reactivated later in life by stress or illness, especially conditions that lead to a weakened or suppressed immune system, such as cancer, organ transplants or advanced age. It is only possible to develop shingles if you have had chickenpox.
When the virus reactivates, it travels up the nerve in which it has lain dormant to the surface of the skin, where it causes painful lesions. These are usually restricted to an area of the skin served by a particular nerve, known as a dermatome. The rash is therefore usually restricted to one particular area of the body and is usually unilateral rather than bilateral.
Shingles is very uncomfortable and may become complicated in some cases, especially if it affects the ears or eyes or if a secondary bacterial infection affects the lesions.
Shingles is treated with antivirals and pain-management medications, and most people recover well within two weeks. Some, however, experience ongoing pain and discomfort in the affected area; this is known as post-herpetic neuralgia.