Dermatopathology Flashcards
Lesions with viral skin/mucosa infections
They are frequently transient, resolving on their own without therapy
Cutaneous viral infections are of greates concern in
Immunosuppressive individuals, as viral reactivation/dissemination can lead yo significant morbidity and mortality
-HIV, steroid use, organ transplant patient
Latency of viral skin infections
Many remain latent and can reactivate or not. Can still shed viral particles and not know it
Symptoms of molluscum contagiosum
- Frequently asymptomatic
- umbilicated papules with pearly/waxy appearance, usually in clusters
What is the classical patten of molloscum contagiosum if there are symptoms
Umbilicated papules, with pearly/waxy appearance
-solid lesion, elevated with sunken centers
Why does molluscum contagiosum usually occur in clusters?
Because it spreads easy
Autoinnoculation
-usually in a Lila, anogenital folds, popliteal fossa
Epidemiology of molluscum contagiosum
- children
- sexually active
- males >females
What family of virus is molluscum contagiosum
Poxvirus family
Sign of healing in molluscum contagiosum
Erythema (redness) around lesions
Primary concern with molluscum contagiosum
- disfigurement (hyperpigmentation)
- transmission to sexual partners
Why is there hyperpigmentation when viral skin infections are healing
Constant inflammation, deposits melanin.
How long does molluscum contagiosum last
Self-limiting: body usually clears infection in 6 months (unless immunosuppressed)
Molluscum contagiosum in immunosuppressed patients
Diffuse lesions common
May appear in the conjunctiva, producing a unilateral conjunctivitis
Treatment for molluscum contagiosum
- cryosurgery
- curettage
- electrodessication
- topical antiviral
Do we always treat everyone who has molluscum contagiosum?
No, usually only in immunosuppressed
Were can you see HPV
Everywhere
What does HPV cause
- subclinical infection (many dont know they have it)
- clinical lesions
- pre-malignant lesions, leading to some cancers
How many types of HPV are there ?
>150 Common warts Plantar warts Flat warts Conjunctival papilloma Genital warts Carcinoma in situ (CIS) lesions and squamous cell carcinoma
Who is more likely to get verruca vulgaris
Very common esp amount school age children
Resolution of verruca vulgaris
Tend to resolve spontaneously, except in many adults and immunocompromised
How is verruca vulgaris transmitted
Skin to skin transmission, virus infects keratinocytes
Not dependent on fluid
Where are verrucae confined to
Epidermis, no “root” or “mother wart”
What is pathognomonic for warts
Black dots
-not in all warts, but can help distinguish from callus
clinical presentation of verrucae
- black dots
- absence of fingerprint lines
Predisposing factors in verrucae
Impaired immunity (HIV infection, transplant recipients, chemo)
Pregnancy
Occupation: handling raw meat and fish
Verrucae morphology
Infected keratinocytes-epidermal hyperplasia
Hyperkeratosis
Produces papules with plaque like coverings
What types of HPV clause conjunctival papilloma
6 and 11
- most often in fornix or palpebral conjunctica
- pedunculated (not flat, very raised, sometimes on a stalk)
How is herpes simplex classically presented
As grouped vesicles with erythematous base
What are most HSV infections?
Atypical
- subclinical lesions; or erosions, fissures
- instead of classically presented grouped vesicles with erythematous base
Transmission of HSV
Can occur in the absence of symptoms
Skin to skin, skin to mucosa, or mucosa to skin
What percent of people are aware that they actually have HSV
10%
How does HSV infect
Virus replicates in epithelial cell, causing lysis and vesicle formation
HSV-1
Above neck
HSV-2
Below waist
Latency of HSV
Ascends peripheral sensory nerves and enters sensory or autonomic nerve root ganglia and remains latent
-neurons can be infected in the absence of clinical lesions/symptoms
What is someone at risk for that has HSV
Risk of aseptic meningitis or recurrent sciatica
Recurrences in HSV
Can impact any region that is innervated by the infected sensory nerve (not limited to primary inoculation site)
-genital inoculation may recur on buttocks or anus
How long is HSV infection
For life
-recurrences can happen at any time, even 81 years down the line)
Factors for recurrence of HSV
Occurs in 1/3rd of individuals with mouth lesions
-50% will have at least two recurrences annually
Triggers of HSV recurrence
Skin/mucosal irritation, menstruation, medications, other infections (colds), immunosuppression
How long do HSV lesions last
2-4 weeks
Signs and symptoms of HSV
- prodromal phase: tingling, pain, burning, sensation, itching
- swelling
- pain
- fever
- lymph nodes may enlarge
HSV sores
- erythematous papules
- vesicles fragile, rupturing easily, to form erosions
Most common site of primary infection of HSV
Mouth
Anogenitalia
Hands/fingers
HSV of fingers
Before “universal precautions”, Herpetic Whitlow, resulting in painful infections of fingers and forearms. This would be something a dentist would get from working in a patients mouth who had HSV
Herpetic facial paralysis and HSV
Reactivation of geniculate ganglion infection implicated in pathognesis of indiopathic facial palsy (Bell’s palsy). HSV-1 shedding detected in 40% of cases
Ocular infection of HSV
Recurrent dendritic keratitis is a major cause of corneal scarring and visual loss
Is recurrent dendritic keratitis from HSV due to HSV1 or HSV2
1, unless in neonate, then it would be 2
Ocular infections from HSV other than recurrent dendritic keratitis
- disciform
- uveitis
- blepharoconjunctivits
Treatment for HSV
Oral antiviral medications
Topical ointments not very helpful
Initial infection of varicella zoster
90% of cases in children <10 yo
Transmission of varicella zoster
Airborne droplets and direct contact with lesions
- pts contagious before lesions appear
- crusts not infectious
VZV infects what
Mucosa of upper respiratory tract/oropharynx, replicates in the mononuclear phagocyte system, and secondary viremia spreads to skin/mucous memebranes, it then spreads to sensory nerves
VZV reactivation
Pain and vesicular lesions develop after VZV reactivates (herpes zoster)
- similar to HSV, ZVZ infections remain latent in nerve until reactivated by stress or immunosuppression
- most patients >50
Where is VZV (herpes zoster) reactivation most common
In the trigeminal, cervical, thoracic, lumbar, or sacral dermatome
Prodrome and VZV
May be preceded by prodromal pain and/or itching
Herpes zoster ocular involvement
- Hutchinson sign (rash at nose tip) increased risk of ocular involvement
- blepharoconjunctivitis
- episcleritis
- may also lead to facial palsy
Classic acute skin problems
Urticaria
Eczema
Erythema multiforme
Classic chronic inflammatory dermatoses
- psoriasis
- seborrheic dermatitis
Urticaria (hives) most common in
20-40 yo but seen in all ages
Symptom or urticaria
Wheals
-develop and fade within hours, but episodes may persist for months
Predisposed sites for urticaria
Trunk, distal extremities, ears
What causes the wheals in urticaria
Localized mast cell degranulation-dermal microvascualr permeability
IgE dependent urticaria
IgE Ab sensitized to antigen (food, pollen, etc)
Antigen-induced release of vasoactive mediators from mast cell granules
IgE independent urticaria
Some substances directly incite mast cell degranulation in some individuals
-opiates, some abx, NSAIDS, cold
Cold urticaria
Holding ice cubes on the skin can also cause urticaria
Eczema features
Red, oozing, crusted lesions that develop with time into raised, scaling plaques
Types of eczema
Contact dermatitis Atopic dermatitis Drug related eczematous dermatitis Eczematous insect bite reaction Photo eczematous eruption Primary irritant dermatitis
Most famous example of this is poison ivy
Contact dermatitis
Is poison ivy contagious
The liquid in the vesicles is not, but the oils are
Antigen responsible for poison ivy, causing contact dermatitis
Urushiol
Skin reaction caused by furocoumarin chemicals (psoralens) in the plant and exposure to UV A sunlight
Phytodermatitis
-lime juice on the beach
How is edema in eczema distinguished from hives?
Eczema is in the epidermis: break and crust, thinner layer, more likely to rupture
Hives are in the dermis, never breaks the skin
-edema in stratum spinosum pushes keratinocytes apart-spongiosis