Herpes zoster, also known as zoster or shingles, is a condition in which painful vesicles or sores develop, typically as a rash on the skin. It is often found wrapping around the body from the middle of the breastbone to the back but can be found anywhere. It is caused by the varicella-zoster virus. This is the same virus that causes chickenpox.
Viral Latency
If a person is infected with the chickenpox virus, as long as the immune system is working normally, the symptoms will reside and the person overcomes the illness. However, the virus does not leave the body. Instead, it hibernates in the nerves of the spinal cord. Later in life it can become active. At that time, it travels along the distribution of a nerve in the skin and produces symptoms.
Age
The incidence of shingles increases with age. Children may get shingles, but people are much more likely to develop shingles as they age. It is particularly more common after age 50. About half of people older than 50 develop zoster. Ongoing nerve pain, called postherpetic neuralgia, is a complication of shingles and also more common with increasing age.
Cancer and Chronic Disease
It is more likely for people with cancer and chronic kidney and lung diseases to develop shingles. A study of shingles in the journal "Clinical Infectious Diseases" in 2009 included 20,357 patients--5,771 with cancer, 10,163 with chronic lung disease and 2106 with kidney disease. All three of these conditions were independently associated with an increased rate of zoster of about 150 percent.
Immune Disorders
Immune disorders predispose people toward the development of shingles. Corticosteroids such as prednisone are used to suppress the immune system. They are used in many disorders such as rheumatoid arthritis and severe asthma. Since they suppress the immune system, they increase the risk of zoster. Other conditions of immune suppression include transplant patients who receive immune suppressive drugs to prevent rejection of the transplanted organ, HIV and autoimmune diseases such as inflammatory bowel disease.
References
- "Harrison's Principles of Internal Medicine"; Anthony Fauci et al; 17th Ed 2008
- "Clinical Infectious Diseases"; Herpes Zoster Risk Factors in a National Cohort of Veterans with Rheumatoid Arthritis; Jay McDonald et al; May 2009
