Module 13.2 - Herpes Zoster

Question 1

What is and what causes herpes zoster (shingles)?

Answer 1

Herpes Zoster, better known as shingles, is a form of the Varicella-zoster virus (VZV). It results from the reactivation of endogenous latent VZV infection within the sensory neurons.

• Characterized by a prodromal unilateral pain usually present for 48 hours prior to rash development
• Rash consists of a unilateral vesicular eruption which usually follows a single dermatome distribution

Question 2

What are some subjective findings associated with herpes zoster?

Answer 2

• Malaise, fever- low grade, headache
• Prodromal symptom of pain- stabbing, burning along affected dermatome precedes vesicular eruptions by 2-3 days

Question 3

What are the physical exam findings associated with herpes zoster?

Answer 3

• Lymphadenopathy
• Vesicles grouped along 1-2 contiguous dermatomes. Rarely non-contiguous
• Initial papules progress to vesicles and bullae within 48 hours; crusting forms in 7-10 days; new lesions can appear up to 1 week.
• Post herpetic neuralgia pain can persist for 1 month or longer post rash; may require referral to pain management if severe
• If trigeminal nerve (tip of nose) is involved, &/or ophthalmologic symptoms, refer to Ophthalmology immediately.

Question 4

What lab/diagnostic tests are used to diagnose herpes zoster?

Answer 4

• Usually diagnosed on clinical presentation and history along
• VZV antigen detection: clinical findings can be confirmed by direct fluorescent antibody obtained from the vesicle base or fluid (up to 82% sensitivity)
• Viral cultures have low sensitivity and take up to 2 weeks for results.

Question 5

How do you manage a patient with herpes zoster?

Answer 5

A. Ophthalmic zoster- Ophthalmologist referral ASAP due to potential complications

B. High risk groups – refer to Infectious Disease/Oncologist for patients with history of

• HIV/AIDS
• Hodgkin’s disease

C. 50-50-50 rule for anti-viral therapy- treat if patient fits in one of the following categories:

• Over age 50 yrs.
• 50 hours or less since onset of lesions
• More than 50 lesions on exam

Acyclovir (Zovirax) 800mg five times daily – accelerates healing of skin lesions if given within 48 hours of onset of rash. Reduce dosage for kidney disease.

Severely immunocompromised patients- hospitalized- give acyclovir 10mg/kg IV q 8 hours for 7-10 days; switch to oral therapy after 3 days if good response noted; adjust for renal impairment

Alternative medications:

• Famciclovir 500mg tid
• Valacyclovir 10000mg tid x 7-10 days
• Foscarnet 90mg/kg IV q 12 hours for immunocompromised patients who fail to respond to acyclovir

Question 6

When should adults be given the varicella vaccination?

Answer 6

recommended to be given in 2 doses to adults > 60 years of age without prior evidence of immunity, except for pregnant or immunocompromised patients