Shingles

Shingles (Herpes Zoster)

Definition
Shingles is a reactivation of the varicella-zoster virus (the same virus that causes chickenpox), leading to a painful, blistering skin rash typically confined to one side of the body along a single dermatome.

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Cause

• After chickenpox infection, varicella-zoster virus remains dormant in sensory nerve ganglia

• Reactivates years later when immunity wanes due to age, illness, or immunosuppression

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Risk Factors

• Age >50 years

• Immunosuppression (HIV, chemotherapy, long-term corticosteroid use)

• Physical or emotional stress

• Chronic diseases (e.g., diabetes)

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Pathophysiology

• Reactivation in dorsal root or cranial nerve ganglia

• Viral replication causes inflammation of nerve and skin supplied by the affected nerve

• Leads to neuropathic pain and vesicular rash

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Clinical Features

Prodromal Phase (1–5 days before rash)

• Localized burning, tingling, or shooting pain in one dermatome

• Malaise, headache, mild fever

Rash Phase

• Erythematous patches evolving into grouped vesicles

• Unilateral, dermatomal distribution

• Vesicles crust over in 7–10 days

• Common sites: thoracic dermatomes, trigeminal nerve (especially ophthalmic branch)

Post-herpetic Phase

• Pain persisting >90 days after rash healing (post-herpetic neuralgia)

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Complications

• Post-herpetic neuralgia (most common)

• Herpes zoster ophthalmicus (can cause vision loss)

• Bacterial superinfection of lesions

• Neurological: meningitis, encephalitis, myelitis

• Hearing loss or facial paralysis (Ramsay Hunt syndrome)

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Diagnosis

• Usually clinical based on unilateral, dermatomal vesicular rash

• PCR or direct fluorescent antibody testing from vesicle fluid if uncertain

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Treatment

Antiviral Therapy (start within 72 hours of rash onset for best effect)

• Acyclovir 800 mg orally five times daily for 7 days

• Valacyclovir 1 g orally three times daily for 7 days (preferred for easier dosing)

• Famciclovir 500 mg orally three times daily for 7 days

Pain Management

• Paracetamol 500–1000 mg every 4–6 hours (max 4 g/day)

• Ibuprofen 200–400 mg every 6–8 hours as needed

• Severe pain: codeine or tramadol short-term

• Neuropathic pain: amitriptyline 10–25 mg at night or gabapentin 300 mg TID (titrate as tolerated)

Skin Care

• Keep lesions clean and dry

• Loose clothing to reduce irritation

Special Cases

• Ophthalmic involvement → urgent ophthalmology referral

• Immunocompromised patients → consider IV acyclovir 10 mg/kg every 8 hours for 7–10 days

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Prevention

• Zoster vaccine (Shingrix®) recommended for adults ≥50 years and high-risk individuals ≥18 years

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Quick-Reference Clinical Chart — Shingles

Feature	Details
Cause	Reactivation of varicella-zoster virus
Risk Factors	Age >50, immunosuppression, stress, chronic illness
Symptoms	Prodrome: localized pain/tingling → unilateral vesicular rash along dermatome
Common Sites	Thoracic dermatomes, trigeminal nerve
Complications	Post-herpetic neuralgia, vision loss, bacterial infection
Antiviral Treatment	Acyclovir 800 mg PO 5×/day × 7 days OR Valacyclovir 1 g PO TID × 7 days OR Famciclovir 500 mg PO TID × 7 days
Pain Control	Paracetamol 500–1000 mg Q4–6h PRN, Ibuprofen 200–400 mg Q6–8h PRN, neuropathic pain meds if needed
Special Management	Ophthalmology referral if eye involvement; IV acyclovir if immunocompromised
Prevention	Shingrix vaccine for ≥50 years or high-risk adults