Varicella Zoster

Question 1

Define Varicella Zoster

Answer 1

Varicella/chickenpox is caused by human alpha herpes virus, varicella zoster, a childhood exanthema

Reactivation of VZV leads to Herpes Zoster/shingles

Question 2

Aetiology of Varicella Zoster

Answer 2

VZV is a human ds-DNA virus with incubation period of 14 days. Exposure is via direct contact with lesions or through airborne spread from resp. droplets. Patients are infectious up to 5 days until all lesions have crusted over

Varicella is the primary infection with VZV is a non-immune host. Clinical disease is a manifestation of the second viraemic phase of the virus (day 9)

After initial presentation the virus establishes lifelong latency in the cranial nerves and dorsal root ganglia

Herpes results from reactivation of latent VZV in the dorsal root ganglia and cranial nerves

Question 3

What is Ramsey-Hunt syndrome

Answer 3

reactivation of the varicella zoster virus in the geniculate ganglion of CNVII

Question 4

Risk factors for Varicella and Zoster

Answer 4

Age 1-9
Exposure to varicella
Unimmunised status
Occupation exposure

>50 years
Female
HIV 
Chronic corticosteroid use
Chemo 
Malignancies 
White

Question 5

Epidemiology of Varicella Zoster

Answer 5

Found worldwide and is very contagious
Over 90% of unimmunised people become infected, but at different parts of the world
More prevalent in temperate climates, and outbreaks more common in late winter and spring
Nearly 100% of individuals have VZV by adulthood
Higher incidence of Zoster in women

Question 6

Symptoms of Varicella

Answer 6

Rash: first centrally (face, scalp, torso) -> extremities
Fever (<38)
Vesicles on the mucous membranes (nasopharynx)
Pruritus
Headache
Prodromal fatigue/malasie
Sore throat

Question 7

Symptoms of Zoster

Answer 7

Facial pain (burning, stinging, itching, tingling | pain precedes the rash by days-weeks)
Pruritus
Erythematous facial rash (pustulate + crust formation)
Pain and reduced vision (Corneal ulceration)
Fever
Headache
Prodromal malaise or fatigue
Pain without rash

Question 8

Signs of Varicella on examination

Answer 8

Vesicular rash (dew drop on a rose petal | first centrally (face, scalp, torso) before spreading to extremities | macules -> fluid-filled vesicles -> scab over)
Fever (<38)
Vesicles on the mucous membranes (nasopharynx)
Tachycardia

Question 9

Signs of Zoster on examination

Answer 9

Localised pain in a dermatome (burning, stinging, itching, tingling | pain precedes the rash by days-weeks | most commonly thoracic and trigeminal dermatomes)
Erythematous maculopapular rash (eruption in segments innervated by the affected ganglion | pustulate + crust formation)
Corneal ulceration
Fever

Question 10

Symptoms and Signs of Ramsay Hunt syndrome

Answer 10

VII and VIII involvement: Vertigo, otalgia, altered taste perception, tinnitus, ipsilateral facial paralysis, ocular pain, vesicular rash around the ear

Signs: vesicles in the ear on otoscopy

Question 11

Investigations for Varicella Zoster

Answer 11

PCR: positive for varciella zoster
Viral culture: +ve for virus
Direct fluorescent antibody testing (DFA): +ve for varicella zoster antigen
Tzanck smear: Multi-nucleated giant cells under microscopic evaluation
Latex agglutination: positive (pregnant women who are exposed and have an unknown immune status
ELISA: +ve for Ig Varicella
Complement fixation: positive IgG for varicella
HIV test: ?

USS: ?foetal abnormalities

Question 12

Management for varicella

Answer 12

Children (healthy otherwise)

• Analgesia e.g. Paracetamol 15mg/kg orally or rectally
• Antihistamines e.g. Diphenhydramine 6.25mg every , double dose as age increases from 6-12 and again >12
• Calamine lotion

Moderate disease: oral aciclovir (>2), 20mg/kg 4x for 5 days, 800mg if >40kg

Severe disease: IV aciclovir, dose varies with age

Question 13

Management for Zoster if there are acute symptoms and the patient is immunocompetent

Answer 13

1. Famciclovir 500mg orally every 8 hours for 7 days (within 72hrs of onset) OR valaciclovir orally every 8 hours for 7 days
2. Mild pain: Paracetamol 500-1000mg orally every 4-6 hours AND calamine lotion topical
3. Moderate-severe pain: Oxycodone 5mg orally (imm. Release) every 4-6 hours when required ± topical lidocaine or calamine

Question 14

Management for Zoster if there are acute symptoms and the patient is immunocompromised

Answer 14

1. Aciclovir 800mg orally 5x daily for 7-10 days OR 10mg/kg IV
2. Paracetamol 500-1000mg orally every 4-6 hours AND calamine lotion topical
   ± Oxycodone 5mg orally (imm. Release) every 4-6 hours when required ± topical lidocaine or calamine

Question 15

Management for Zoster post-herpetic pain

Answer 15

1. Paracetamol, codeine phosphate, ibuprofen, gabapentin, pregabalin
2. Capsaicin topical (0.025-0.075%)
3. Tramadol 50-100mg orally every 4-6hours when required for moderate-severe pain

Question 16

Management for Ramsy-Hunt syndrome

Answer 16

Oral acyclovir 7-10 days and corticosteroid e.g. prednisolone for 5 days

Question 17

Complications of Varicella

Answer 17

Secondary bacterial infection
Varicella pneumonitis or pneumonia 
Varicella encephalitis
Meningitis
Intracranial vasculitis 
Hepatitis 
Cutaneous scarring 
Reye's syndrome
Herpes zoster

Question 18

Complications of Zoster

Answer 18

HZ ophthalmicus 
Superinfection of skin lesions
Encephalitis 
Transverse myelitis 
Varicella zoster retinitis 
Disseminated zoster

Question 19

Prognosis for Varicella Zoster

Answer 19

Varicella is typically a self-limiting disease and after initial infection and syndrome, no follow-up is necessary
Up to 1/3 of infected people, VZV reactivates later
Can be life-threatening in the immunocompromised
Ocular complications occur in 50%-90% of cases -> temporary or permanent decreased acuity or blindness if untreated