Intro
Shingles (herpes zoster) is a painful condition caused by the reactivation of the varicella-zoster virus (VZV) — the same virus responsible for chickenpox. After a person has chickenpox, the virus remains dormant in the nervous system. Years or decades later, often when immunity declines with age, illness, or treatment, the virus can reactivate — travelling along nerve fibres to the skin and causing a painful, blistering rash.
Shingles affects about one in three people over the course of a lifetime, with risk rising sharply after age 50. It is not usually life-threatening in otherwise healthy adults, but it can be very painful and its most common complication — post-herpetic neuralgia — can cause debilitating pain lasting months to years. A highly effective vaccine is available and is the most important preventive measure.
Key Points
- Shingles is caused by reactivation of the varicella-zoster virus in people who have previously had chickenpox.
- It typically causes a one-sided, painful rash along a nerve — often preceded by days of pain or tingling before the rash appears.
- Early antiviral treatment within 72 hours of rash onset reduces severity and lowers the risk of post-herpetic neuralgia.
- Post-herpetic neuralgia — persistent nerve pain — is the most significant complication and becomes more common and severe with increasing age.
- The recombinant shingles vaccine (Shingrix) is approximately 90% effective and is recommended for adults aged 50 and over.
- Shingles involving the eye, ear, or face requires urgent medical assessment.
Background
Varicella-zoster virus (VZV) is a member of the herpesvirus family. Primary infection causes chickenpox, typically in childhood. After the acute illness, VZV does not leave the body — it retreats into sensory nerve ganglia (particularly the dorsal root ganglia) and remains in a latent state. Immune function normally keeps the virus suppressed. If immune surveillance declines — due to ageing, illness, or immunosuppressive treatment — the virus can reactivate, travelling along the sensory nerve to the area of skin it supplies.
Shingles almost always follows a dermatomal distribution — affecting a strip of skin on one side of the body or face, corresponding to the specific nerve that reactivated. This one-sided, band-like pattern is one of its most recognisable features.
Causes or Mechanisms
Anyone who has had chickenpox carries VZV latently in their nerve cells and is at lifelong risk of shingles.
Factors that increase the risk of reactivation:
- Age: immune function declines with age (immunosenescence), making reactivation more likely. Risk rises sharply after 50 and continues increasing with each decade.
- Immunosuppression: HIV infection, haematological malignancies, solid organ cancers, transplant medications, corticosteroids, and biological therapies all substantially increase risk.
- Acute illness or physical stress: severe infections or major surgery may temporarily suppress immune function enough to trigger reactivation.
Shingles arises from the person’s own dormant virus — it does not require contact with another infected person.
Symptoms
Prodrome (before the rash)
In most cases, shingles begins with a prodromal phase lasting 1–5 days before the rash appears:
- Pain, burning, aching, or tingling on one side of the body or face
- Sensitivity to touch (allodynia) in the affected area
- Itching or numbness
- Fatigue, low-grade fever, or headache
Pre-rash pain can be confused with other conditions — pleurisy, kidney stone, heart attack, appendicitis, or dental pain — depending on the affected dermatome, before the rash reveals the diagnosis.
Active rash phase
- Small red spots appear in the affected dermatome
- Fluid-filled blisters (vesicles) form over 3–5 days
- Blisters break open, weep, and begin to crust over
- The rash is confined to one side of the body along the nerve’s distribution
- Common locations: one side of the trunk, face, or neck
The rash remains capable of transmitting VZV until all blisters have fully crusted over — typically 7–10 days from onset.
Resolution
The rash typically heals within 2–4 weeks. In some people — particularly older adults — nerve pain persists in the affected area after the rash resolves (post-herpetic neuralgia).
Diagnosis
Shingles is usually diagnosed clinically — by the characteristic one-sided, dermatomal, painful blistering rash in someone with a history of chickenpox or varicella vaccination.
If the diagnosis is uncertain — particularly before the rash appears or in atypical presentations — laboratory confirmation is available:
- PCR testing of vesicle fluid or a skin swab: the most accurate method.
- Blood tests for VZV antibodies are not useful for diagnosing acute shingles.
Treatment
Antiviral medications
Antivirals limit VZV replication and are most effective when started within 72 hours of rash onset.
- Valacyclovir (1,000 mg three times daily for 7 days): preferred in most adults; well absorbed.
- Famciclovir (500 mg three times daily for 7 days): comparable to valacyclovir.
- Acyclovir (800 mg five times daily for 7–10 days): effective but more frequent dosing required.
Antivirals are recommended for:
- All adults aged 50 and over with shingles
- Any adult with moderate to severe rash, significant pain, or ophthalmic or facial involvement
- Immunocompromised individuals — who may need higher doses, longer treatment duration, and specialist guidance
Even if slightly beyond 72 hours, antivirals may still benefit people with ongoing new lesion formation or severe disease.
Pain management
Shingles pain can be severe. Options include:
- Paracetamol and NSAIDs for mild pain
- Short-term opioids for severe acute pain
- Neuropathic pain agents (gabapentin, pregabalin, amitriptyline) — particularly if post-herpetic neuralgia is developing or anticipated
- Topical agents: cool compresses or calamine lotion may soothe; topical lidocaine may help localised pain
Post-herpetic neuralgia treatment
When pain persists after the rash has healed, it is classified as post-herpetic neuralgia (PHN). Options include:
- Tricyclic antidepressants (amitriptyline, nortriptyline): evidence-based for neuropathic pain
- Gabapentin or pregabalin: effective for neuropathic pain
- Topical capsaicin patch or cream: reduces neuropathic pain signal transmission
- Topical lidocaine patches
- Opioids: may be needed for severe, refractory PHN
PHN can be difficult to treat and may require referral to a pain specialist. Prevention through vaccination and early antiviral treatment is far more effective than managing established PHN.
Wound care
Keep the rash clean and dry. Avoid picking at blisters. Loose, breathable clothing reduces irritation. Wash hands after touching the affected area.
Complications
Post-herpetic neuralgia (PHN)
The most common and most feared complication. Pain persists in the affected dermatome for months to years after the rash resolves — often described as burning, shooting, electric, or constant aching pain. PHN significantly impairs quality of life and sleep.
Risk by age:
- Under 40: PHN is uncommon
- Age 60–70: approximately 15–25% develop PHN
- Over 70: risk exceeds 30%
Ophthalmic zoster
When shingles involves the ophthalmic branch of the trigeminal nerve (V1), it causes rash around the eye and forehead — herpes zoster ophthalmicus. This requires urgent ophthalmology review because it can cause keratitis, uveitis, and permanent vision damage if untreated.
Hutchinson’s sign — a rash on the tip of the nose — suggests ophthalmic nerve involvement and indicates the eye is likely at risk.
Ramsay Hunt syndrome
Reactivation in the facial nerve (cranial nerve VII) can cause:
- Ear pain and rash in or around the ear
- Facial nerve palsy (one-sided facial drooping)
- Hearing loss, vertigo, or tinnitus
This requires urgent specialist assessment. Early antiviral and corticosteroid treatment improves outcomes.
Other complications
- Bacterial superinfection of the rash (cellulitis)
- Encephalitis or meningitis (rare; more likely in immunocompromised people)
- Motor weakness (uncommon; motor nerve involvement adjacent to the affected sensory nerve)
When to Seek Urgent Care
See a doctor the same day if:
- You have a one-sided painful rash or burning/tingling pain — antiviral treatment within 72 hours is important
- You notice a rash on your forehead, around your eye, or on the tip of your nose
Seek emergency care immediately if:
- The rash involves the eye or is causing visual changes
- You develop facial weakness, hearing changes, or vertigo alongside a rash (Ramsay Hunt syndrome)
- You are immunocompromised and develop a severe or rapidly spreading rash
- You develop confusion, severe headache, neck stiffness, or other neurological symptoms
Prevention: The Shingles Vaccine
Vaccination is the most effective means of preventing shingles and its complications, particularly post-herpetic neuralgia.
Recombinant shingles vaccine (Shingrix, RZV)
- Efficacy: approximately 90% effective at preventing shingles; over 89% effective at preventing post-herpetic neuralgia in adults aged 50+.
- Schedule: two doses, 2–6 months apart (can be given 1–2 months apart in immunocompromised individuals).
- Recommended for: most adults aged 50 and over, regardless of prior shingles or prior chickenpox illness.
- Immunocompromised adults aged 19–49: also recommended given their elevated risk.
- After a prior shingles episode: vaccination is still recommended to reduce the risk of recurrence.
- Side effects: arm soreness, fatigue, headache, and muscle aches are common and often significant enough to affect daily activities for 1–2 days. This reflects an active immune response, not illness.
The older live attenuated vaccine (Zostavax) is no longer widely available in most countries where Shingrix is offered; Shingrix is substantially more effective and is safe for immunocompromised people (for whom live vaccines are contraindicated).
See also: Shingles Vaccine in Adults
Risks, Benefits, and Prognosis
Most immunocompetent adults recover from shingles fully within 2–4 weeks. The main risk is persistent post-herpetic neuralgia, which is more likely and more severe with older age.
In immunocompromised individuals, shingles may be more severe, disseminated (spreading beyond a single dermatome), or associated with systemic complications. Specialist management is essential in this group.
Early antiviral treatment reduces:
- Severity and duration of the acute illness
- Risk of post-herpetic neuralgia
- Severity of ophthalmic complications
Vaccination reduces the risk of shingles by approximately 90% and, if shingles occurs despite vaccination, tends to be milder.
FAQ
Q: Can you get shingles more than once? A: Yes. Recurrence is uncommon — estimated at around 1–6% within a few years — but does occur. Vaccination after a first episode is recommended to reduce recurrence risk.
Q: Can children get shingles? A: Shingles is uncommon in children but can occur — particularly in children who had chickenpox in infancy. Children who received the varicella (chickenpox) vaccine have a lower risk than unvaccinated children who had natural chickenpox.
Q: How long is a person with shingles contagious? A: A person with active blisters can transmit VZV to chickenpox-susceptible contacts. They remain potentially contagious until all blisters have fully crusted over — typically 7–10 days from rash onset. Once all blisters are crusted, the rash is no longer contagious.
Q: Does stress cause shingles? A: Stress alone does not reliably trigger shingles, but physical or psychological stress can temporarily suppress immune function, potentially contributing to reactivation. Age and immune-compromising conditions are the most significant risk factors.
Q: I had the old shingles vaccine (Zostavax) — do I need Shingrix? A: Yes. Most guidelines recommend that adults who received the older live zoster vaccine should also receive the recombinant vaccine (Shingrix), as Shingrix is substantially more effective and its protection is more durable. Discuss timing with your doctor.