Herpes Zoster (Shingles)

INTRODUCTION

Cranial nerve involvement

The trigeminal nerve—15% of all cases:

• ophthalmic branch—50% affects nasociliary branch with lesions on tip of nose and eyes (conjunctivae and cornea)

• maxillary and mandibular—oral, palatal and pharyngeal lesions

The facial nerve: lower motor neuron facial nerve palsy with vesicles in and around external auditory meatus (notably posterior wall)—the Ramsay–Hunt syndrome.

Management

• Appropriate detailed explanation and reassurance. Dispel myths.

• Explain that herpes zoster is only mildly contagious but children can acquire chickenpox after exposure to a person with the disorder.

Topical treatment For the rash, use a drying lotion such as menthol in flexible collodion.

Oral medication

1. Analgesics (e.g. paracetamol + ibuprofen co)

2. Guanine analogue antiviral therapy for:

   • – all immunocompromised

   • – any patient provided rash present <72 h (esp. those >60 yrs)

   • – ophthalmic zoster (evidence to date—reduces scarring and pain but not neuralgia)

   • – severe acute pain

Drugs and dosage

• Aciclovir 800 mg 5 times daily for 7 d or

• Famciclovir 500 mg 8 hrly for 7 d (10 d if immunocompromised) or

• Valaciclovir 1 g 8 hrly for 7 d

POSTHERPETIC NEURALGIA

Definition: pain persisting at least 3 mths after vesicles crusted.

Increased incidence with age and debility, with duration greater than 6 mths.

• Resolves within 1 yr in 70–80% but in others it may persist for years.

• Eye complications of ophthalmic zoster, including keratitis, uveitis and eyelid damage.

Treatment options

Oral medication

• Basic analgesics (aspirin or paracetamol or NSAID or combination orally)

• Tricyclic antidepressants (e.g. amitryptiline 10–25 mg (o) nocte starting dose, to maximum 100 mg nocte) or

• Gabapentin 100–300 mg (o) daily (nocte) initially ↑ as tolerated to tds or

• Pregabalin (for lancinating pain) 75 mg (o) nocte initially ↑ as tolerated

Topical medication

• Capsaicin (Capsig) cream. Apply the cream, which can ‘burn’, to the affected area 3–4 times/d (apply ice massage, 20 mins before).

• Lignocaine 5% patch to painful area

Prevention

A single varicella zoster vaccine is recommended for adults (not immunocompromised) aged 60 years and over. It has been part of the National Immunisation Program for those up to 79 years.

Consider giving varicella zoster immune globulin to contacts of patients who are immunosuppressed and have no history of varicella.