HERPES ZOSTER

(Shingles)

An acute cutaneous infection involving primarily the dorsal root ganglia, usually of a single dermatome. It is
characterised by a vesicular eruption in areas supplied by peripheral sensory nerves in the affected root ganglia.

Cause

  • Herpes Zoster Varicella zoster virus, usually reactivated from the virus that entered the cutaneous nerves during an earlier episode of chicken pox and remained in a latent form. This usually occurs during low immunity.

Clinical features

  • Pre-eruptive pain, itching or burning: generally localized to the dermatome, precedes the eruption by 4-5 days
  • The above are followed by characteristic crops of very painful vesicles on the side supplied by affected nerve
  • Mild chills, fever, malaise

Differential diagnosis

  • Chicken pox
  • Herpes simplex

Investigations

  • Clinical diagnosis is sufficient
  • Serology test for HIV, if sero-status not known

MANAGEMENT

Symptomatic and supportive treatment

  • Clean lesions with antiseptic, e.g. chlorhexidine solution 0.05%
  • Or diluted hydrogen peroxide solution 6%
  • Apply calamine lotion 2–3 times daily
  • Analgesics for neuropathic pain e.g. amitriptyline 25 mg nocte, or carbamazepine
    200 mg nocte as necessary
  • Oral aciclovir 800 mg 5 times a day for 7 days can be given, especially if the disease is diagnosed
    very early or is disseminated

If the lesions involve the eye

  • Refer to an ophthalmologist (Eye Specialist)

Prevention

  • Protect high-risk individuals (e.g. the immunosuppressed) from direct contact with the disease