Overview
Shingles (herpes zoster) is a viral infection causing a painful blistering rash, caused by reactivation of the varicella-zoster virus (VZV), which also causes chickenpox. After a chickenpox infection, VZV lies dormant in nerve cells. Decades later, it can reactivate, travelling down a nerve to the skin to produce a distinctive one-sided rash. The most serious complication is post-herpetic neuralgia, persistent pain lasting months or years after the rash heals.
How common is it?
About 1 in 4 people in the UK will develop shingles at some point. Risk rises sharply with age. About 50,000 cases occur each year in England. The UK NHS offers shingles vaccination to those aged 70 to 79.
Causes and risk factors
Declining immunity with age, immunosuppression, or physical or emotional stress allows dormant VZV to reactivate in dorsal root ganglia and travel down the sensory nerve.
Common risk factors
- Age over 50 (risk increases sharply)
- Immunosuppression: HIV, cancer, immunosuppressive drugs (steroids, chemotherapy, biologics)
- Physical or psychological stress
- Previous chickenpox infection (required for VZV to be dormant)
Symptoms
- Prodrome 2 to 4 days before rash: burning, itching, tingling or pain along the affected nerve, sometimes with fever and malaise
- Rash: red area developing into clusters of fluid-filled blisters along a dermatome (a band of skin supplied by one nerve)
- Rash is strictly one-sided and does not cross the midline
- Blisters crust over and heal in 2 to 4 weeks
- Post-herpetic neuralgia: burning or stabbing pain persisting at the rash site after healing
- Ophthalmic shingles (involving the eye branch of the trigeminal nerve) — risk of corneal scarring and blindness
When to see a doctor
Start antiviral treatment within 72 hours of rash onset for best effect. Seek urgent ophthalmology assessment for shingles involving the eye or tip of the nose (Hutchinson sign). People on immunosuppressants should seek same-day review.
Diagnosis
Clinical diagnosis based on the characteristic one-sided dermatomal rash. PCR swab from blister fluid confirms VZV if atypical. Pre-rash diagnosis based on dermatomal pain pattern.
Treatments
Antiviral medication
Valaciclovir 1g three times daily or aciclovir 800mg five times daily for 7 days. Most effective when started within 72 hours of rash onset. Reduces severity and duration and importantly reduces risk of post-herpetic neuralgia.
Pain management
Paracetamol and NSAIDs for mild pain. Amitriptyline, pregabalin, or gabapentin for neuropathic post-herpetic neuralgia. Opioids short-term for severe acute pain. Topical lidocaine or capsaicin patches for localised PHN.
Shingles vaccination
Recombinant zoster vaccine (Shingrix) is 90% effective at preventing shingles and 90% effective at preventing post-herpetic neuralgia in vaccinated individuals. Two doses 2 to 6 months apart. Given to those over 70 on the NHS.
Self-care and lifestyle
- Keep the rash clean and dry to prevent bacterial infection
- Avoid contact with pregnant women (who have not had chickenpox), newborns, and immunosuppressed people while blisters are present
- Do not scratch blisters — scarring and bacterial infection can result
- Stress reduction supports immune recovery
Prevention
Shingrix vaccine (Shingrix) is the most effective prevention — 90% efficacy even in those over 70. Maintaining good general health and immune function reduces reactivation risk.