Human Herpesviruses Flashcards
How many human herpes viruses that we need to know?
8 (HHV-1 through 8)
What type of virus is the human herpes virus?
Double-stranded DNA virus w/ a glycoprotein-containing envelope.
Where do the human herpes viruses replicate?
The host nucleus
What diseases do HSV1 and HSV2 cause?
Both cause recurrent vesicular eruptions. HSV1 is classically orolabial and HSV2 is classically genital although this is changing.
Where does the herpes virus remain dormant after primary infection?
In sensory nerve dorsal root ganglion
Risk factors for genital herpes?
Age 15-30 years, increased number of sexual partners, lower-income/educations, HIV + (also works in reverse, this increases the risk of HIV), MSM
How does HSV1/2 evade the immune system?
Decreases expression of CD1a by APC’s, decreased TLR receptor signaling.
What are some reactivation triggers for HSV?
Stress, UV (UVB>UVA), fever, injury (chemical peel or fractionated laser) and immunosuppression
Clinical appearance of HSV1/2
Grouped/clustered vesicles on a red base. Note that this can become pustules, erosions (look for scalloped borders due to coalescence), ulcers, and will ultimately crust over
Lasts about 6 weeks to completely resolve
What is the presentation of primary versus recurrent HSV1/2?
After 3 to 7 days postinfection–>prodromal sx’s (tender LAD, malaise, anorexia, and fever)–>mucocutaneous lesions. There can be pain, tenderness, tingling just before lesions erupt
- Recurrent lesions are generally milder than primary infections. Can have a 24 hr prodrome of burning, itching, tingling
What is a key difference between herpangina and orolabial herpes infection?
Herpes tends to affect the buccal mucosa and anterior mouth (recurrent herpes tends to affect the vermillion border). Whereas, herpangina is the posterior mouth/pharynx
In which sex does primary genital herpes tend to be worse?
It is usually worse in women as they are more at risk for extragenital involvement. Watch for urinary retention and aseptic meningitis (10%).
How long does a recurrent episode of genital herpes last?
Approximately 1 week
What is the primary HSV infection like in genital herpes?
Often asymptomatic, but can have LAD, dysuria (more in women), painful/tender lesions on the external genitalia, vagina, cervix, buttocks, and perineum (women)
What is eczema herpticum and what disorders is it seen in?
It is a widespread, sometimes severe HSV infection on areas with skin barrier disruption. These disorders that increase the risk include: atopic dermatitis (namesake), Darier’s, Hailey-Hailey
What virus usually causes eczema herpeticum?
HSV-1, associated with Th2 shift in immune status
Atopic dermatitis risk factors for eczema herpeticum?
Severe atopic dermatitis, children with onset of AD <5 years old, increased IgE levels, increased eos, and food/environmental allergies
What is herpetic whitlow and what virus most commonly causes it?
It is HSV on the digits. HSV1 is more common in children and HSV2 is more common in adults
What is herpes gladiatorum and where does it normally present?
It is an HSV infection from athletic contact (wrestling, etc). It is most commonly seen on the face/neck and forearm (think areas with contact in sports)
What do we call it if we see herpetic vesicles in the beard area (follicular based)?
HSV folliculitis (herpetic sycosis)
What other surfaces must be considered for HSV infection in severely immunocompromised?
Can also involve the respiratory and GI tracts in the severely immunosuppressed
What is seen clinically in ocular HSV?
Keratoconjunctivitis w/ lymphadenopathy and branching dendritic corneal ulcer.
What herpes viruses are most common in ocular HSV?
HSV-2 in children, HSV-1 in all else
What part of the brain is most often affected in HSV encephalitis?
Temporal lobe
What gene mutations might be associated with getting HSV encephalitis?
TLR-3 or UNC-93B
How is a diagnosis of HSV made?
- Viral culture: low sensitivity, high specificity
- Direct fluorescent antibody assays, Western blot (gold standard)
- PCR (most sensitive/specific)
- Tzanck smear
What is the histology of HSV infections?
Look for intraepidermal vesicle with slate-gray enlarged keratinocytes from ballooning degeneration and viral changes of margination of the chromatin (most sensitive sign)
Can also see Cowdry A inclusion bodies which are eosinophilic inclusions in the nucleus
Will also see varying degrees of epidermal necrosis and infiltrate
Treatment for recurrent orolabial herpes?
Oral penciclovir/valacyclovir, topical penciclovir, or topical acyclovir/hydrocortisone comb
What is the treatment for recurrent genital HSV?
Oral acyclovir/famciclovir/valacyclovir.
- Meds need to be given within 48 hrs of starting to decrease sx’s and viral shedding
Who receives suppressive daily medications for herpes infections?
Those patients have >6 outbreaks per year
In what settings would you consider IV acyclovir for an HSV1/2 infection?
Eczema herpeticum may need it, neonatal HSV, HSV in immunosuppressed patients
What medications can be given in cases of resistant HSV ( and who is at risk for resistant HSV)?
Foscarnet and cidofovir, immunosuppressed patients are more likely to have resistant HSV
What is the most common cause of Erythema multiforme minor?
HSV-1
What is a significant cause of death in patients with disseminated zoster?
SIADH
What is the primary and secondary forms of HHV-3/Varicella infection?
Primary = chicken pox (varicella)
Secondary= shingles (herpes zoster)
Who is most at risk of getting zoster/shingles?
The elderly and immunosuppressed, this also increases the risk for disseminated dz
Other risk factors: physical and emotional stress, feer, trauma, and immunosuppression
When are patients with varicella contagious?
1-2 days before the eruption starts until all the lesions have crusted over
How is varicella transmitted?
Aerosolized droplets and direct contact with lesional fluid
Pathogenesis of primary to secondary infections in varicella/zoster?
The zoster virus goes into the dorsal root ganglion and remains dormant until re-activated, when it replicates and travels own sensory nerves to the skin
Who gets more severe primary infections with varicella?
Adults and adolescents
What is the clinical appearance of primary infection with varicella?
Cephalocaudal progression of classic “dew-drops on a rose petal” vesicles on an erythematous base that become pustular and then crust
The vesicles will come in crops, so you will see different vesicles at different stages