Reactivation of the varicella zoster virus which can lie dormant in nerve ganglia following primary infection (chickenpox)
Aetiology
Commonly occurs in the elderly and shingles in young adults should prompt investigation for an underlying immune condition
Clinical features
Can manifest first as a tingling feeling in a dermatomal distribution
Progresses to erythematous papules occurring along one or more dermatomes within a few days, which develop into fluid-filled vesicles which then crust over and heal
May be associated with viral symptoms e.g. fever, headache, malaise
May affect the eye if the trigeminal nerve is involved, causing corneal ulcers
Management
Oral antiviral (e.g. valaciclovir 1g three times per day for 7 days) if eye involvement or if immunocompromised.
IV antiviral if severe disease
Advise avoiding contact with pregnant women, babies and those who are immunocompromised until the lesions are fully crusted over, as transmission can occur via skin contact
Complications
Secondary bacterial infection of skin lesions
Corneal ulcers, scarring and blindness if eye involved
Post-herpetic neuralgia
Pain occurring at site of healed shingles infection
Can cause neuropathic type pain (burning, pins and needles)
Can cause allodynia (perception of pain from a normally non-painful stimulus e.g. light touch)
