====Shingles (Herpes Zoster)====
  *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

===Management===
  *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

====Herpes Zoster Ophthalmicus====
  *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

====Ramsay Hunt syndrome type II====

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.

----
^  <WRAP center round box info 90%>pharmacological agents</WRAP>  ^|
^  ^  anti viral  ^
^acyclovir  | • inhibit HSV polymerase, thereby inhibiting replication\\ • //**Dose:**// 800mg 5x daily  ^
^valaciclovir  |• more effective than acyclovir\\ • //**Dose:**// 1000mg tds  |
^  ^  analgesia  |
^simple analgesia  |• paracetamol +/- codeine, NSAIDs   |
^anti-convulsants  |//**Gabapentin**//\\ • GABA analogue but does NOT bind those rec's\\ • excreted unchanged in urine\\ • //**Dose:**// d1 = 300mg, d2 = 300mg bd, d3 = 300mg tds then as needed\\  |
^ :::|//**Pregabalin**//\\• GABA analogue binds to subunit of Ca++ channels in CNS\\  • //**Dose:**// 50-100mg tds   |
^tricyclics  |//**amitriptyline**//\\ • inhibition of serotonin and NorAdrenaline reuptake. May also bind opioid rec's\\ • //**Dose:**// 10-25mg daily then titrated to effect  |


----
**References include**\\ 
[[https://www.aafp.org/afp/2017/1115/p656.html| Prevention and Mx of Herpes Zoster - AFP 2017]]\\ 
https://emedicine.medscape.com/article/1132465-treatment\\ 
[[https://www.who.int/selection_medicines/committees/expert/21/applications/s2_gabapentin.pdf?ua=1| WHO submission for Gabapentin as Rx for neuropathic pain]]\\ 
[[https://academic.oup.com/bja/article/99/6/775/247971| 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\\