Viral Infections of the Skin Flashcards by Barrett Thompson

What are the two types of Herpes Simplex (HSV) and where are they typically found?
• what percentage of adults have abs to these?

HSV-1
• Perioral, Lips, Oral Cavity
• 85% of adults have antibodies to this virus

HSV-2
• Genital
• 20-25% of adults have abs to this

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HSV
• How is it spread? when do you realize you got it?
• Where does it go?
• When can you get infected?

Spread via SKIN to SKIN contact and symptoms appear 3 to 7 days after exposure. It spreads most often via sensory nerves to Ganglia where the infection can be latent.

Infection can happen during Recurrences and during Asymptomatic Viral Shedding

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What type of genome does HSV have?

HSV has a dsDNA genome

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How does a primary Herpes Simplex infection feel?
• compare a recurrent infection to this.

Primary Infection:
• Pain, Burning, Tingling, Fever, Mailase, LAD

Recurrent Infection:
• Milder

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What are some Triggers of HSV?

Fever
Sun exposure (cold sores)
Stress

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**What are some key features that you need to look for in Herpes Simplex Infections?

Monomorphous Vesicles with an ERYTHEMATOUS BASE (very important for differentiating it from other conditions)
punched out (cookie cutter si

milarity) erosions and crusted papules

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What key feature is seen here?
• what is this?

Erythematous Background to cookie cutter pustules

This is Herpes Simplex I most likely

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What type of herpes is this?

Genital Herpes = HSV-2

HSV-1 shown below on lips (crusty)

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Somone presents with this lesion. What do you do to confirm the diagnosis?
• what are you looking for?

Open a fresh vesicle to do a Tzanck Smear and you’re looking for **multinucleated giant cells to confirm the dx
You can also do aViral Culture or PCR**

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You need to culture HSV to confirm the Dx. Until cultures come back what else could be in your differential?

Impetigo (top) 
Aphthous Stomatitis (middle) 
Syphilitic Chancre (bottom)

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A person got a Tzank smear that showed this?
• significance?

They have Herpes

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How do you treat HSV?
• Mild?
• Severe?

Mild HSV:
• Topical Antiviral

Moderate to Severe HSV:
• Systemic Antiviral (oral or IV)

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Herpes Zoster (VZV)
• what is it?
• What are the chances of getting this?
• Who is at the greatest risk of getting this?

Herpes Zoster = Shingle => Reactivated VZV

Risk of Reactivation is 20-30%:
• People over 60 and the Immunosuppressed are at extremely high risk

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Where does Varicella (herpes) Zoster Virus hide?
• what is the genome like for this virus?
• what are some triggers?

VZV sits latent in the dorsal root ganglion its a dsDNA virus

Triggers:
• Trauma
• Stress
• Fever
• Radiation
• Immunosuppression

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How does someone typically present with a Herpes Zoster reactivation?

Often they have pain, itching, and burning before the lesions appear (may in their back etc.)aka PRODROME. When lesions do appear they are dermatomal (b/c this virus lives in nerves). Most often this occurs on the TRUNK.

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What location can VZV reactivate in that is particularly dangerous?
• what are some associated complications?
• How often does this happen?

Trigeminal Nerve Reactivation -> Happens in 10-15% of cases
V1 Opthalmic Distribution Reactivation:
• Nasociliary Branch
• BLINDNESS

V2 and V3:
• Facial Palsy
• Tinnitus, Vertigo, Deafness

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Why should you be worried when someone has Shingles and you see vesicles at the tip of their nose?

This is Hutchinson’s Sign. It indicates that the reactivation is in the V1 branch of trigeminal and blindness could be a complication.

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How long does it take Shingles to Resolve?
• are there any long-term consequences?

Takes 3-5 weeks to resolve typically

Postherpetic Neuralgia occurs 5-20% of the time (mostly in people over 40)

What characteristics let you know that this is Herpes Zoster (shingles)?

Single Dermatome affected

See below for opthalmic nerve reactivation of VZV

What is a key way to differentiate Herpes Simplex from Herpes Zoster?

Herpes Zoster STAYS in a DERMATOME, Simplex does not stay in a dermatome. Simplex is also less painful.

How would you confirm the diagnosis of Herpes Zoster?

*Tzanck Smear** (mutinucleated giant cells)
*Viral Culture** (not practicle for VZV)
*PCR**

What is the treatment for Shingles?
• What can you do to prevent it? how effective is this?

Shingles
• Treat withing 72 hours with Oral Antiviral
• Pain Meds needed

Prevention:
• Vaccine for all people 60 years and older
• Decreases risk by 1/2 and neuralgia by 2/3

Molluscum Conatgiosum
• genomic structure
• Transmission
• duration of infection

Molluscum Contagiosum = POX VIRUS
• Large dsDNA virus with CYTOPLASMIC inclusions

Transmission:
• Skin to Skin or autoinoculations/fomites

Duration:
• Infection may resolve completely in Months to Years

What does Molluscum Contagiosum look like?
• common locations?

Key Features of MC:
• Pink to Skin colored 2-10mm DOME-SHAPED WAXY PAPULES
• ± central umbilication (important feature but not always present)

Commonly found on:
• Chest, Face, Extremities

What key features are seen here? • disease? • what's in your differential?

Molluscum Contagiosum from Pox dsDNA complex structured virus Important notes: • Waxy dome-shaped papules without central umbilication in this case Differential: • Acne • Folliculitis

What is shown here? • Infection?

Molluscum Contagiosum: Waxy Papules WITH central umbilication • NOTE this is NOT a superimposed bacterial infection, instead it suggests that the immune system is responding to the infection and it may soon resolve

How do you rule Acne and Folliculitis out of the DDx for Molluscum Contagiosum?

Acne: • has comedones that LACK umbilication Folliculitis: • Papules or Pustules, no umbilication NOTE ALSO that BOTH OF THESE CONDITIONS MUCH OCCUR AT A HAIR FOLLICLE, Molluscum contagiosum does not.

What is the preferred Treatment for Molluscum Contagiosum? • what is it?

Cantharidin • Chemical Vesicant - may cause minor pain and erthema but is pretty effective and typically painless

What Virus is responsible for Warts? • Genome? • How is it transmitted?

**HPV causes warts small circular dsDNA virus in an icosahedral capsid** **Transmission:** Can occur **directly via Hetero or Autoinoculation** OR **indirectly via Fomites** may get on warm, moist surfaces like **towels** and get on you like that

What stains of HPV are known to be oncogenic? • does gardasil cover these?

16, 18, 31, 33 are oncogenic genotypes but only 16 and 18 are covered by gardasil which covers (6, 11, 16, and 18)

How does the Transmission of HPV occur? • how long before you are symptomatic? • is it lifelong? If not how do we combat it?

HPV is transferred from fomite or directly into **TRAUMATIZED skin** (so that it can infect the stratum basal). It then i**ncubates for 1 to 6 months** and after **2 years about 67% of these resolve** as a result of **cell mediated immunity (CTLs).**

What are the 4 types of Warts caused by HPV?

* Verrucae Vulgaris (common warts) * Verrucae Plantaris (plantar warts) * Verrucae Plana (flat warts) * Condylomata Acuminata (angogenital warts)

How do common warts (HPV) present? • Key clues to Dx?

**Most common** these are on the **hands** (either *periungula or subungual, but could be on ANY mucosal surf*ac*e*) and may be single or multiple skin-colored **hyperkeratotic papules and/or plaques that are Dome shaped, Exophytic, or on a filiform stock.** Clues to Dx: • **Black Dots (seeds) from thrombosed capillaries on paring the surface** **• Disruption of normal skin lines**

What type of wart is shown here?

Common wart -\> Filiform Variant (typically found on the face)

What is shown here? • key features?

These are FLAT WARTS Keys: • Smooth Skin-colored to slightly tan/pink flat-topped thin paules and/or plaques

What should you advise your patient with these NOT to do?

Don't Shave over the Flat Warts b/c that just facillitates the spread Note how the patient here has scratched to facillitate spread in a linear fashion by damaging the tissue and allowing viral entry

Plantar Warts • Typical location? • Symptoms? • Wart characteristics?