Herpes Varicella-Zoster (Shingles) Infection

💉 The national vaccination campaign recommends immunisation in adults over 70 to prevent shingles and postherpetic neuralgia. 👁️ Also see related topics on Herpes Zoster Ophthalmicus and Varicella (chickenpox).

📖 About

• 🔬 Herpes viruses are double-stranded DNA viruses.
• 🌬️ Spread by droplet transmission → highly contagious.
• 🧒 Most people gain immunity in childhood, but virus may reactivate later in life → shingles.
• 🎯 Targets the skin, eyes, and nervous system.

🦠 Virology

• Varicella → chickenpox; Zoster → shingles.
• ⏳ Incubation: 10–21 days.
• 🧠 Virus remains latent in dorsal root ganglia or cranial nerve nuclei.

🩹 Shingles

Characteristic belt-like rash, unilateral, confined to a single dermatome.

⚠️ Severe, extensive, or prolonged disease should raise suspicion for immunosuppression (e.g., HIV). 👉 Chickenpox can be caught from shingles, but not the other way around.

🩺 Clinical Presentation

• 🔥 Sharp, burning pain precedes rash (typically 2–3 days).
• 🌡️ Fever, malaise, itching, tingling.
• 🩹 Rash: grouped vesicles on erythematous base, confined to dermatome.
• 👶 Children: chickenpox → crops of vesicular lesions + fever.
• 👨 Adults: higher morbidity/mortality (15× that of children).
• 🤰 Pregnancy: risk of varicella pneumonitis.
• 🧠 Complications: pneumonitis, encephalitis (20% fatality), hepatitis, thrombocytopenia.

🔎 Other Manifestations

• ⚡ Postherpetic neuralgia: persistent neuropathic pain.
• 👁️ Herpes Zoster Ophthalmicus: corneal involvement (ophthalmic branch of CN V).
• 👂 Ramsay Hunt syndrome: facial palsy + vesicles in ear canal.
• 🧠 Neurological: transverse myelitis, Guillain-Barré syndrome, stroke syndromes (zoster vasculitis).

🚬 Risks for Varicella Pneumonia

• Smoking
• Pregnancy
• Immunosuppression
• Male sex

🧑‍⚕️ Immunocompromised Patients

• 💥 More severe, widespread, or prolonged disease.
• High-risk groups: HIV (low CD4), transplant recipients, patients on steroids/azathioprine/TNF antagonists, malignancy, pregnancy.

🧪 Investigations

• 🩸 Baseline bloods: FBC, U&E, LFT, CRP.
• 🧫 Vesicle fluid: PCR, EM, fluorescent antibody test.
• 🔍 Assess for immunodeficiency or cancer red flags.

🛠️ Primary Care Management

• 💊 Start oral antiviral within 72 h: e.g., Aciclovir 800 mg 5× daily × 7 days.
• 💡 Provide analgesia: paracetamol ± codeine; consider amitriptyline/gabapentin if neuropathic pain.
• 👕 Keep rash covered; avoid contact with non-immune, pregnant, or immunocompromised individuals until crusted over.
• 🗣️ Reassure: usually self-limiting but risk of postherpetic neuralgia.
• 📅 Follow-up if pain >4 weeks or rash becomes widespread (screen for immunosuppression).
• 💉 Discuss zoster vaccination for future prevention (if not already given).

🏥 Hospital Management

• 🚪 Isolate; only immune staff should provide care.
• 💊 Antivirals (start ≤72h of rash):
  • Aciclovir 800 mg 5× daily × 7 days
  • Famciclovir 500 mg tds × 7 days
  • Valaciclovir 1 g tds × 7 days
• 🧑‍⚕️ Immunocompromised: same drugs but longer course (continue 2 days post-crusting).
• 💊 Pain relief: paracetamol, codeine ± neuropathic agents.
• 👩‍⚕️ Pregnant/breastfeeding: consult microbiology before antivirals.

⚡ Postherpetic Neuralgia

• Chronic neuropathic pain after shingles.
• ⬆️ Risk with age and severe acute pain.
• Options: amitriptyline, gabapentin, duloxetine, topical capsaicin, lidocaine patches.
• Tramadol: short-term rescue only (avoid long-term).

🛡️ Prevention

• 💉 National shingles vaccine ≥70 yrs to reduce incidence and neuralgia.
• 👩‍🍼 Exposed non-immune pregnant/immunocompromised → Zoster Immunoglobulin (ZIG) within 10 days.
• 💊 If infection develops → treat with aciclovir; seek microbiology advice.

📚 References

• NICE CKS: Shingles (2019)