What are the causes of shingles?
Shingles affects individuals who have previously had an attack of chicken pox. It is caused by the second eruption of the virus and is more commonly seen in elderly people due to their ageing and weak immune system.
The varicella zoster virus, which causes the shingles, belongs to the herpes family. The virus, after causing chicken pox during childhood, remains dormant or quiet in the nerve cells near the spine. Other herpes virus cause cold sores and genital herpes.
A weak immune system reawakens the varicella virus, causing shingles. The immune system may be weakened by -
- Certain medications like steroids, chemotherapy drugs and immunosuppressive drugs to prevent rejection of organ transplants.
- Certain diseases, like cancer and HIV
Once active, the virus travels along the path from the nerves to the skin, leaving a trail of destruction along the nerves through which they travel. The result is the manifestation of pain and rashes, characteristic of shingles.
No one is sure of what re-activates the quiet virus. Sometimes stress or a minor infection can trigger an attack.