• due to reactivation of dormant varicella zoster virus, usually after some form of immuno-compromise eg. age, illness, stress
  • a mild non-specific 'viral' illness may then precede the rash
  • vesicles usually crust over ≤10/7 after rash begins and then no longer infectious
• clinical diagnosis usually based on dermatomal pain and eruption of grouped vesicles in the same dermatome with pain usually preceding the rash and therefore making the diagnosis at times.
  • most common dermatomes affected: T1-L2. Ophthalmic division of trigeminal affected in around 15% cases
• pain can persist for months after rash which will usually last ≤4/52
• polymerase chain reaction (PCR) testing of vesicle or other fluids is highly sensitive and specific

• analgesia
  • simple analgesia and NSAIDs
  • amitryptiline, nortriptiline are effective for post-herpetic neuralgia
  • gabapentin and pregabalin also useful
  • topical agents: lignocaine, capsaicin
• anti-virals
  • eg acyclovir, effective and best started within 72/24 of rash
    • some debate about whether reduces incidence of post-herpetic neuralgia but probably reduce shedding and healing time if given early (<72/24)
    • 800mg 5 times daily
  • Valaciclovir - reported to have greater overall effectiveness than aciclovir as it produces higher levels of antiviral activity in blood
    • 1g tds for 7/7 https://bnf.nice.org.uk/drug/valaciclovir.html
  • IV acyclovir for complicated Zoster or ophthalmic zoster
• Glucocorticoids
  • similar debate as anti-virals about effectiveness
  • adjunct to anti-viral Rx, may reduce pain and promotes early healing of rash
• Varicella Zoster vaccine available for prevention

• IV acyclovir
• topical antibiotic cream
• topical steroids - with Ophthalmologist direction/supervision
• cycloplegic agents for pain relief

Hutchinson’s sign refers to the presence of vesicular lesions on the nose due to involvement of the nasociliary branch of the trigeminal nerve

• uncommon, but a good predictor of ophthalmic complications

Also known as herpes zoster oticus - rare complication of shingles involving the geniculate ganglion of the facial nerve.

• generally present with lesions in the ear and side of the tongue and facial paralysis.
• Other symptoms - loss of taste and, if the vestibulocochlear nerve is affected, vertigo and tinnitus.
• may initially be difficult to differentiate from Bell’s palsy, but Bell’s palsy is usually painless and does not affect the ear or tongue.

References include
Prevention and Mx of Herpes Zoster - AFP 2017
https://emedicine.medscape.com/article/1132465-treatment
WHO submission for Gabapentin as Rx for neuropathic pain
gabapentin review
https://bnf.nice.org.uk/drug/gabapentin.html
https://reference.medscape.com/drug/lyrica-cr-pregabalin-343368#10
https://bpac.org.nz/BPJ/2014/March/herpes.aspx