Shingles is a painful blistering rash caused by the same virus that causes chickenpox, known as the varicella (chickenpox) zoster (shingles) virus.
What causes shingles?
After a person has had chickenpox, the virus remains dormant in some of the nerves linked to either the spinal cord or nerves of the head and neck region. If the virus becomes active again, it multiplies and moves along the nerve fibres to the area of skin supplied by those nerves; shingles then appears in this area.
You can only get infected with shingles if you have had chicken pox. About 1 in 5 people who have had chickenpox will have an attack of shingles later in life.
Most attacks of shingles occur for no obvious reason, but an attack is more likely if:
- You are elderly. Likelihood increases with age.
- You are experiencing physical or emotional stress.
- You have an illness that weakens the immune system, such as leukaemia, lymphoma (e.g. Hodgkin’s disease) or HIV infection.
- You are taking treatments that suppress the immune system, includingradiotherapy for cancer, chemotherapy, steroid drugs, and drugs taken to prevent organ rejection.
Is shingles contagious?
Shingles itself is not caught from someone who has shingles. It develops when the dormant herpes zoster virus becomes active, for example when a person’s immune defences are weaker than normal. However, a person with shingles can pass on chickenpox to someone who has never had chickenpox. A person with shingles is infectious from the point of blister development up until the blisters crust over (approximately 7 days).
