Molluscum Flashcards
In molluscum contagiosum? most commonly affected?
children
sexually active adults
athletes participating in contact sports
individuals with impaired cellular immunity
Molluscum contagiosum transmission?
Common benign cutaneous viral infection
Skin to skin contact
What age group in molluscum?
before the age of 14 years old
median age of 5 years
MC lesions?
Mainly limited to the skin, but rarely develop on mucosal surfaces, including the eye
In children lesions are usually found where?
exposed areas
In adults lesions are usually found where?
many cases are limited to the genital area, suggesting sexual transmission
In adults lesions typically develop in the genital area
MC infections are more common in individuals infected with?
HIV
Transmission in molluscum occur via?
direct skin or mucous membrane contact fomites Bath towels swimming pools public or shared baths autoinoculation koebnerization vertical transmission from mother to neonate during the intrapartum period
where does MC live?
in the epidermis
does NOT remain latent in the body after the cutaneous lesions have cleared
MC often presents as?
Small pink, pearly, or skin-colored papules that enlarge to 2 to 5 mm in size?
Lesions may have a? in molluscum
Central dell or umbilication from which a white curd-like substance containing the virus can be expressed with pressure
Lesions may be grouped in clusters or appear in a linear array
where does children usually develop MC?
children usually develop multiple papules,
often in exposed sites like the face and extremities or intertriginous sites, such as the axillae and popliteal fossae
does molluscum contagiosum result from koebnerization or development of lesions at sites of trauma?
Lesions may be grouped in clusters or appear in a linear array
How big can molluscum develop in immunosuppressed patients?
May develop giant molluscum as large as 2.5 cm in diameter
Is molluscum associated with systemic complications?
NO.
What are the complications of MC?
- pruritus (particularly in those patients with underlying atopic dermatitis)
- Chronic conjunctivitis and punctate keratitis may develop in patients with eyelid lesions)
- secondary bacterial infection can occur, particularly if patients scratch their lesions
How many percent of patients develop Molluscum dermatitis?
19 to 39% of children develop this.
Describe molluscum dermatitis
erythematous, eczematous dermatitis surrounding their molluscum lesions
Molluscum dermatitis is more common in children with?
atopic dermatitis
roughly half of children with both atopic dermatitis and MC develop molluscum dermatitis
The development of inflamed MC lesions suggest what?
A robust immune response and tends to be associated with a subsequent decline in the number of lesions
Does a small subset of individuals with MC develop a Gianotti-Crosti-like reaction?
Yes. A small subset of individuals with MC develop a Gianotti-Crosti-like reaction consisting of
- pruritic, monomorphous, edematous, erythematous papules or papulovesicles
- centered on the elbows and knees, which lasts for several weeks
- eruption tends to be followed by reduction in the number of MC lesions and may be considered a favorable prognostic sign
What is the etiologic agent of Molluscum Contagiosum?
Molluscum contagiosum virus
Describe the MC virus.
It is a large, brick-shaped DSDNA poxvirus
What strain of MC virus is responsible for 98% of the disease?
MC virus genotype 1
MC virus genotype 2 is primarily seen in?
Adults and immunocompromised individuals
Most commonly transmitted by sexual contact.
How long is the incubation period of the virus?
approximately 2-6 weeks.
Where does MC virus replicate?
in the cytoplasm of epithelial cells.
Where does viral inclusion bodes (Henderson Paterson bodies) develop?
In the basal layer of the epidermis.
They enlarge as cells rise through the epidermis, pushing cellular organelles against the sides of the cell.
What happens whens there is proliferation and enlargement of the virion packed cells?
Disintegration of the stratum corneum and the formation of a dimple-like ostium through which the virions are released when the inclusion bodies rupture
Can molluscum lesions persist for a long time without significant inflammatory cell infiltration?
yes because MC virus possess multiple genes that impede host response
a) coding for a homolog of a major histocompatibility class I heavy chain, which may interfere with antigen presentation
b) a chemokine homolog that inhibits chemotaxis
c) a protein that inhibits apoptosis by preventing activation of the death effector domain of caspase 8
d) glutathione peroxidase homolog that prevents apoptosis in cells damaged by UV radiation and hydrogen peroxide
Eventually the immune system detects the MC virus and mounts a localized response involving what?
- plamacytoid dendritic cells
- interferon-induced dendritic cells
- natural killer cells
- cytotoxic T lymphocytes
Ultimately clearing the infection…
