Viral Herpes Flashcards
What is viral herpes
Common, life-long infection cause by human herpes viruses.
Cause cold sores, genital herpes, chicken pox, and shingles.
Herpes are infectious, latent, and can be reactivated.
Pathophysiology of viral herpes
Once infected (usually in childhood by skin-to-skin contact), virus is latent in spinal dorsal root nerves.
During a reactivation, virus travels along nerve to skin or mucous membrane where it multiplies and causes blisters.
After each infection, virus re-enters latent/resting state.
Primary infection= Mild mouth inflammation or chickenpox
Recurrence= cold sore or shingles
Signs and symptoms of viral herpes
Localised blistering
Oral and facial lesions
Genital and rectal infections
Classification of herpes
Simplex = HSV1 and HSV2
- HSV1= cold sores or recurrent herpes
- HSV2= genital herpes.
Varicellovirus = varicella-zoster virus
- chickenpox or shingles
Explain varicella-zoster
Primary infection = chickenpox
Chickenpox starts as prodromal phase 1-2 days (fever, lethargy), then itchy pink papules.
Why does herpes reactivate?
After initial infection, there may be no further episodes.
Trigger factors for HSV1&2=
- minor skin trauma
- upper respiratory tract infections
- sun, cold, wind exposure
- hormones (menstruation)
- stress
Trigger factors for VZV
Risk of reactivation increases when VZV immunity declines.
- age
- medical condition
- immunosuppressants
Differentially diagnose HSV1&2
Insect bites- not in groups
Drug reaction - uniform
Impetigo- shingles is painful, impetigo spreads beyond lips
Treatment plan of simple cold sores
Mild uncomplicated eruptions = generally no treatment
Prevent/avoid triggers
Blisters can be covered w/ hydrocolloid patch
Topical or oral antiviral therapy
Start during prodromal period
Non-prescription treatment for simple cold sores
Aciclovir 5% cream - apply every 4 hrs for 4-5 days
Penciclovir 1% cream - apply every 2 hrs for 4 days
Reduce by half a day
Aciclovir 5% and hydrocortisone 1% cream - speed healing, apply 5 times a day for 5 days.
Idoxuridine w/ lidocaine 0.5%/2% cream - apply hourly, then every 4 hrs until disappears.
Famciclovir 500mg oral tablets S3. 1500mg as single dose. Good for severe/disabling cold sores.
Treatment of genital herpes
Initial infection - antiviral drugs
Episodic treatment - mild = no treatment, can use shorter course of antivirals in prodromal period
Severe recurrence- repeated course / continuous prophylactic therapy for few months
Oral antivirals = aciclovir, famciclovir, valaciclovir
Dose and duration depends on initial/reccurent, immunocompetency, chosen antiviral
Treatment of chickenpox (herpes varicella)
Healthy children = non-pharm and symptomatic relief
- trim nails to avoid scratching
- fluid intake to avoid dehydration
- lukewarm bath
- moisturiser
- paracetamol for discomfort/fever
- topical anti-itch (pine tar)
- amorphous hydrogel for healing and hydration
neonates need referral
children w/ pre-existing skin disease = antiviral therapy to reduce risk of severe disease
Adults and immunocompromised = antiviral therapy. depends on duration, severity, and complications.
Treatment of herpes zoster (shingles)
Immunocompotent = antiviral within 72 hrs of rash
famciclovir 500mg for 7 days
valaciclovir 1g for 7 days
aciclovir 800mg for 7 days
Immunocompromised = always need antiviral therapy.
disseminated = hospital and IV
Rest and pain relief
Ice packs and paracetamol for acute neuropathic pain
Topical therapies can be used.
Severe pain may need oral steroids/opioid.
Vaseline on rash
Watch out for bacterial infection.
Referral for herpes
Diagnosis doubts
Suspect shingles or infection
Suspect chicken pox in neonate or adult
Suspect post herpetic neuralgia
Suspect herpes zoster on eye
Lifestyle changes
Vaccination for chickenpox and shingles
Vaccine is not interchangeable.
