Herpes Zoster Clinical Presentation
Herpes zoster typically presents as a painful, vesicular, cutaneous eruption with a dermatomal distribution, usually affecting a single dermatome without crossing the midline 1.
Classic Presentation Features
The characteristic clinical picture includes:
- Painful vesicular rash following a dermatomal pattern along sensory nerve distributions
- Unilateral distribution - lesions typically do not cross the midline 2
- Single dermatome involvement most commonly, though 2-3 adjacent dermatomes may be affected 2
- Prodromal pain often precedes the rash by several days
- Vesicles appear on an erythematous base in the affected dermatome
Pathophysiology Context
The presentation results from reactivation of varicella zoster virus (VZV) that remains dormant in dorsal root ganglia or sensory ganglia of cranial nerves after primary varicella infection 1. The virus spreads orthodromically from the ganglion via the sensory nerve root to innervated target tissues including skin, cornea, and auditory canal 2.
Atypical Presentations to Consider
Important clinical pitfall: Herpes zoster can present atypically, which challenges even experienced clinicians 2:
- Zoster sine herpete - pain in dermatomal distribution without visible rash, can be mistaken for other conditions 2, 3
- Bilateral herpes zoster - rare but documented 2
- Herpes zoster ophthalmicus - affects the ophthalmic division of trigeminal nerve 1, 3
- Ramsay Hunt syndrome - facial nerve involvement causing facial paralysis, ear pain, and vesicles in the ear; facial paralysis without vesicles may indicate zoster sine herpete and be mistaken for Bell's palsy 3
High-Risk Populations
Immunocompromised patients present differently 4:
- More severe and atypical clinical findings
- Higher complication rates
- Greater risk for recurrence
- Higher mortality rates
Diagnosis Approach
Diagnosis is primarily clinical based on the characteristic dermatomal vesicular rash 5, 4. Laboratory virologic testing is reserved for:
- Atypical presentations
- Central nervous system involvement
- Immunocompromised patients with unclear presentations 4
The typical presentation in immunocompetent adults over 50 years requires no confirmatory testing when the classic dermatomal vesicular pattern is present.