What is shingles?

What causes shingles?

Shingles (herpes zoster) is a reactivation of the varicella-zoster virus — the same virus that causes chickenpox. After you have chickenpox, the virus stays dormant in your nerve tissue. Decades later, it can reactivate as shingles.

About 1 in 3 people will develop shingles in their lifetime. The risk increases with age, particularly after 50, but younger adults can get it too. People with weakened immune systems are at higher risk.

How the virus reactivates

The exact trigger for reactivation isn't always clear. Contributing factors include:

• Ageing immune system — natural decline in VZV-specific cell-mediated immunity
• Immunosuppression — chemotherapy, transplant medications, HIV, long-term corticosteroids
• Physical or emotional stress — periods of significant stress may contribute

What does shingles look like?

The characteristic shingles rash appears as a band or stripe of blisters on one side of the body, following the path of a nerve (dermatome). It most commonly appears on the torso, but can affect the face, eyes, or other areas.

Before the rash appears, many people experience pain, burning, tingling, or itching in the affected area — sometimes days earlier.

Transmission

Shingles itself cannot be "caught" from someone else. However, the fluid from shingles blisters contains the varicella-zoster virus. A person who has never had chickenpox (or the chickenpox vaccine) can catch the virus from contact with active shingles blisters and develop chickenpox — not shingles.

If you have active shingles, avoid contact with:

• People who have never had chickenpox
• Pregnant people who haven't had chickenpox
• People with weakened immune systems
• Newborns