What is shingles?
Shingles (also known as herpes zoster) is a painful blistering rash caused by the same virus that causes chickenpox (the varicella zoster virus).
What causes shingles?
If you have had chickenpox the virus that caused it may live on afterwards in a dormant state in the nerves linked to your spinal cord. If the virus becomes active again, it will multiply and move along the nerve fibres to the area of skin supplied by those nerves; shingles then appears in this area. About 20% of people who have had chickenpox will have an attack of shingles later in life.
Shingles is not caught from someone who has shingles, but follows an earlier attack of chickenpox. However, a person with shingles can infect someone who has never had chickenpox, causing an attack of chickenpox but not shingles.
Most attacks of shingles occur for no obvious reason, but an attack is more likely if:
- you are elderly.
- you are under stress.
- you have an illness that weakens the immune system, such as leukaemia, a lymphoma (for example, Hodgkin’s disease), or HIV.
- you are taking treatments that suppress the immune system, including irradiation for cancer, chemotherapy, cortisone-like drugs, and drugs taken to prevent organ rejection.
Is shingles hereditary?
What are the symptoms of shingles?
Pain is the first and predominant symptom and sometimes there is also a tingling or burning sensation. The rash usually appears a day or two after these symptoms. You may also feel ill and have a fever and a headache.
What does shingles look like?
The first sign is the appearance of groups of red spots on a pink-red background, which quickly turn into small fluid-filled blisters. Some of the blisters burst, others fill up with blood or pus. The area then slowly dries out, and crusts and scabs form. The scabs will drop off over the next 2-3 weeks.
The rash usually covers a well-defined area of skin on one side of the body only, and not crossing the midline. Its position and shape will depend on which nerves are involved. Shingles can affect any area, but common patterns include a band running round one side of the chest, or down an arm or leg. Sometimes pale or dark scars follow shingles, particularly after a severe attack.
A chickenpox-like rash occasionally comes up at the same time as shingles. This may indicate a more serious and widespread attack of shingles or that there is an underlying reason for the shingles.
How is shingles diagnosed?
Early in the course of shingles, before the rash is present, it may be difficult to make the diagnosis. Later on the diagnosis is usually straightforward, based on the story of pain appearing before the rash, and on the typical appearance of the rash.
It takes several days to grow the virus in the laboratory to test for shingles so it is not often done as treatment needs to be started quickly. If there is doubt about the diagnosis, scrapings may be taken from a blister and looked at under a microscope.
Can shingles be cured?
Shingles resolves on its own within a few weeks. Oral medication can make the rash of shingles clear more quickly and can reduce its unpleasant effects.
These effects depend largely on which nerve is involved:
- Shingles of the area served by the nerve that carries sensation from the front of the eye can lead to ulceration there, and later to scarring. Blisters coming up on the side of your nose will alert your doctor to this risk, and you should get advice from an eye specialist.
- Muscles supplied by the nerves taking part in the shingles occasionally become weak. For example, a temporary facial paralysis can accompany a shingles rash on the ear.
- The pain of shingles may persist long after the rash has cleared (post herpetic neuralgia), particularly in the elderly. Usually this goes away within 6 months, but a few people are in pain for a year or more.
For information on available treatments please go to this page on the website of the British Association of Dermatologists