Shingles (herpes zoster)

Shingles (herpes zoster) is a painful reactivation of the varicella-zoster virus — the same virus that causes chickenpox. After chickenpox, the virus remains dormant in nerve tissue and can reactivate years later as shingles, typically producing a painful blistering rash in a stripe on one side of the body or face.

Anyone who has had chickenpox can develop shingles. Risk rises with age and with weakened immunity. Vaccination substantially reduces the risk of shingles and of postherpetic neuralgia, the chronic nerve pain that can persist after the rash heals. Antiviral medicines started early can shorten the episode and lower complication risk.

Shingles often begins with pain, burning, tingling, or itching in a band on one side of the body or face, followed within a few days by a rash. Features include:

• Pain that can be intense and may precede the rash by several days
• Red patches followed by fluid-filled blisters that crust over
• Rash usually limited to one dermatome (nerve distribution) and one side of the midline
• Fever, headache, fatigue, and light sensitivity in some people
• Rash on the face that can involve the eye (herpes zoster ophthalmicus) — a vision-threatening emergency
• Rarely, rash involving the ear with facial weakness (Ramsay Hunt syndrome)

The rash typically heals in 2–4 weeks. Pain that continues for months is postherpetic neuralgia.

Shingles is caused by reactivation of latent varicella-zoster virus in sensory nerve ganglia. Declining virus-specific immunity with age or immunosuppression allows reactivation. The virus travels along the nerve to the skin, producing the characteristic painful dermatomal rash. Shingles itself is less contagious than chickenpox, but the blister fluid can transmit varicella to people who never had chickenpox or the vaccine, causing chickenpox (not shingles) in them.

Risk factors include:

• Age 50 and older (risk continues to rise with age)
• Immunosuppression (cancer, HIV, transplant, immunosuppressive medicines including higher-dose corticosteroids)
• Having had chickenpox (required for shingles to occur)
• Stress and certain chronic illnesses may contribute in some people

Possible complications include:

• Postherpetic neuralgia — persistent pain in the distribution of the rash after skin healing; more common with older age and severe acute pain
• Vision loss from herpes zoster ophthalmicus
• Bacterial superinfection of skin lesions
• Neurologic complications (encephalitis, myelitis, stroke syndromes — rare)
• Ramsay Hunt syndrome with hearing loss or persistent facial weakness
• Disseminated zoster in immunocompromised patients

The recombinant zoster vaccine (e.g., Shingrix) is recommended for most adults 50 years and older and for immunocompromised adults 19 years and older (per current guidelines). It is highly effective at preventing shingles and postherpetic neuralgia. Vaccination is still useful for people who previously received the older live vaccine or who have already had shingles (after the acute episode resolves).

Avoid contact with high-risk people (pregnant women who are not immune, premature infants, immunocompromised individuals) while blisters are present and until they crust.

Diagnosis is usually clinical based on the characteristic painful unilateral dermatomal vesicular rash. When the appearance is atypical, PCR testing of lesion fluid can confirm varicella-zoster virus. Eye involvement warrants urgent ophthalmologic examination.

Contact a clinician as soon as you suspect shingles — ideally within 72 hours of rash onset, when antivirals are most effective. Seek urgent care for rash near the eye, ear involvement with facial weakness, widespread rash (possible in immunocompromised people), or severe pain or secondary infection of the skin.

Treatment ideally starts within 72 hours of rash onset:

• Antiviral medicines — acyclovir, valacyclovir, or famciclovir to speed healing and reduce complications
• Pain control — acetaminophen, NSAIDs, and when needed, short-term opioids, gabapentinoids, tricyclic antidepressants, or topical lidocaine/capsaicin for neuropathic pain
• Corticosteroids — sometimes added in selected severe cases under specialist guidance
• Eye involvement — urgent ophthalmology care; topical and systemic antivirals as directed
• Postherpetic neuralgia — neuropathic pain medicines, topical agents, and referral to pain specialists when severe

Keep the rash clean and covered; avoid topical antibiotics unless secondary bacterial infection is present.

During an episode:

• Start prescribed antivirals as soon as possible
• Keep the rash clean and dry; cover vesicles to limit transmission
• Use cool compresses for comfort
• Wear loose clothing
• Take pain medicines as directed
• Avoid scratching
• Stay away from high-risk contacts until lesions have crusted
• Rest and maintain hydration

Bring:

• When pain and rash started and how they have progressed
• Immune-system conditions or medicines that suppress immunity
• Vaccination history (shingles and chickenpox)
• Questions about antivirals, pain control, and whether the shingles vaccine is appropriate after recovery