Vaircella Zoster or Shingles [Herpes zoster] (Viral Skin Infection)

Question 1

Background

Answer 1

Varicella zoster causes shingles and chicken pox

Shingles (herpes zoster) is a viral infection of an individual nerve and the skin surface that is served by the nerve (dermatome).
It’s caused by the reactivation of the varicella-zoster virus, the virus which causes chicken pox.

More common in adults, especially the elderly, sick or immune-suppressed

Question 2

Signs and Symptoms / Diagnosis

Answer 2

Pain, in the areas of sensory nerves emerging from the spine.
Fever, headache and regional lymphadenopathy (enlarged lymph node/s).
Within 1-3 days of the onset of pain, crops of closely grouped erythematous papules develop within the unilateral dermatome(s). New papules continue to appear for several days, each blistering or becoming pustular then crusting over.
- Look red (like bruising) appear around the body.

Diagnosis:
History taking, find risk factors and examine (symptoms etc)

Question 3

Shingles Treatment

Answer 3

Uncomplicated recovery is 2/3 weeks Elderly 3/4 weeks.
Management includes rest, applying povidone iodine to blisters, oral aciclovir and steroids for severe cases and oral antibiotics for secondary infection.
If they get Post-herpetic neuralgia (pain persisting for >90 days after rash onset) they need analgesia.

Management (CKS):
Oral antiviral - aciclovir, valaciclovir, or famciclovir.
Prescribe within 72 hrs of rash if immunocompromised or non truncal or moderate/severe pain/rash.

Doses (extra)
Normal adults: (7 day courses)
Aciclovir: 800 mg 5/day.
Famciclovir: 500 mg TDS, or 750 mg OD/BD
Valaciclovir: 1000 mg TDS.
Immunocompromised same doses but F only 500mg option and 10 day course.
All to be continued 2 days after lesions crusted.

Pain - Mild:
- ibuprofen.
Not effective, or SEVERE pain,
- amitriptyline (off-label),
- duloxetine (off-label),
- gabapentin or pregabalin.
Consider oral corticosteroids in the first 2 weeks following rash onset in immunocompetent adults with localized shingles if pain is severe, but only in combination with antiviral treatment.
children with pain, offer paracetamol.

Prevention
2-dose Shingrix® vaccine
Give to >60 in 2 stages and >70 with 26-52 week gap. Offered if severity of disease is higher or at risk of post herpetic neuralgia.

Question 4

Chicken pox treatment

Answer 4

PT will have small spots on head, face, trunk. limbs. Crust over 5 days and fall off after 1/2 weeks.
- Red small spots loads of them

Self limiting in heathy ppl.
Can use symptomatic treatments:
- Paracetamol
- Topical calamine lotion/ Antihistamine creams
- Chlorphenamine >1yrs

Meds:
Oral aciclovir 800mhg 5/day - 7 days if ≥14yrs if present within 24hrs of rash esp. if severe or at risk of complications ie smokers.

For prevention there is a vaccine for post and pre exposure.

Question 5

Varicella zoster (extra notes)

Answer 5

• Causes chicken pox
  More severe in children
  Antiviral started within 24 hr of rash onset can reduce severity and duration of symptoms.
• Those at risk of complications may need immunoglobulin prophylaxis
• Can give antiviral for immunocompromised adults and children if present within 24 hrs of rash.

Question 6

Drug info

Answer 6

Oral antiviral:
If swallowing is difficult can try dispersible form, need to stay hydrated, use analgesics to reduce pain, wash hands with soap after touching lesions.
F - efficacy decreased in severe hepatic impairment.

AE - GI effects, skin rashes, V - neurological disorders.

Key interactions- Aminophylline and theophylline — aciclovir valaciclovir may increase plasma conc. of them

Vaccine:
- Zostvax:
Contraindicated - immunosuppressive therapy (high dose oral steroid), Untreated TB, P,
AE - injection site reactions.
- Shingrex:
AE - injection site reactions.