Shingles (Herpes Zoster)

🔍 When to Suspect

A prodrome of unilateral pain, tingling, or itching followed by the eruption of a painful, vesicular rash confined to a single dermatome

From the full topic in The Ocean Library: Shingles (Herpes Zoster)

🧭 When to suspect

Shingles (herpes zoster) is reactivation of latent varicella zoster virus (VZV) lying dormant in a sensory ganglion since primary chickenpox. It produces a painful, unilateral, vesicular rash confined to a single dermatome that characteristically stops at the midline. Suspect it whenever an older or immunocompromised patient describes burning, tingling or itching in a band of skin – with or without a rash yet visible.

A prodrome of dermatomal pain, paraesthesia or itch typically precedes the rash by 1–5 days, sometimes with malaise, headache or low-grade fever; occasionally pain occurs with no rash at all (zoster sine herpete). The thoracic dermatomes are most often affected, followed by the ophthalmic division of the trigeminal nerve. Risk rises sharply with age over 50 and with any cause of impaired cell-mediated immunity.

The clinical task in primary care is fourfold: recognise the dermatomal pattern, decide promptly who needs an antiviral within 72 hours, never miss the sight- or function-threatening forms (ophthalmic zoster and Ramsay Hunt syndrome), and offer the Shingrix vaccine to those eligible to prevent it.

Phase	Typical features	Timing
Prodrome	Burning, tingling, itch or pain in one dermatome; sometimes malaise, headache, fever	1–5 days before rash
Eruptive	Erythematous macules/papules → grouped vesicles on a red base → pustules; unilateral, single dermatome, respects midline	Days 0–7
Crusting	Vesicles dry and crust over; patient remains infectious until fully crusted	7–10 days (heals over 2–4 weeks)
Post-herpetic neuralgia	Neuropathic pain persisting at the site after the rash has healed	Pain > 90 days from onset

Source: NICE · UK Health Security Agency

---