1.5 Infectious skin disorders Flashcards
what is it?
-red, tender, swollen rash with fever
cellulitis
how to distinguish SSSS (Staphylococcal scalded skin syndrome) from TEN (toxic epidermal necrolysis)?
- histologically determined:
- SSSS: epidermolysis at stratum granulosum
- TEN: epidermolysis at E-D junction
difference btwn cellulitis and erysipelas, clinical presentation
cellultis: diffuse inflammation
erysipelas: sharply outlined plaques
What lab test to dx Herpes? and what to look for
Tzank test–rapid smear from freshly opened vesicle, use Giemsa stain.
- multinucleated keratinocytes with intranuclear inclusion bodies (‘Cowdry inclusions’). Looks like dark bodies surrounded by halo.
- typical of all HSV infected cells
- acantholysis of epidermis (breakage of keratinocytes)
molluscum contagiosum
-people most commonly affected (3)
- children
- sexually active adults
- immunocompromised
what is it?
-small dome shaped, ‘crater-like’ nodules
molluscum contagiosum
molluscum contagiosum
-histology
- purple inclusion bodies
- ‘Henderson-Patterson bodies”
verruca: what do you see histologically?
- HPV infiltration of squamous keratinocyte (koilocytosis)
- see ‘hollow cells’ in epidermis (nuclear enlargement with surrounding halo)
Erysipelas
- infection of upper dermis (as opposed to deep dermis of cellulitis)
- sharply outlined erythematous, edematous plaques
Verruca
(wart)
- flesh-colored papule, rough surface
- hands, feet
- HPV infection of keratinocytes
cellulitis
- what is it
- clinical findings
- infection of dermis (deeper than impetigo)
- usu S. Aureus, S. pyogenes
- red, tender, swollen rash with fever
how to dx dermatophytoses?
KOH stain, rapid test to see branching hyphae
what is it?
erythematous macules that progress to pustules, rupture results in ‘honey colored crust’
impetigo
impetigo
- what is it
- clinical findings
- superficial bacterial skin infection, usu S. Aureus, S. pyogenes
- erythematous macules that progress to pustules, rupture results in ‘honey colored crust’
what is it?
- flesh-colored papule, rough surface
- hands, feet
verruca (wart)
molluscum contagiosum
- clinical finding
- what microbe
- small dome shaped, ‘crater-like’ nodules
- poxvirus
natural history of verruca
- usually self-limiting
- regress spontaneously from 6 months to 3 years.
staphylococcal scalded skin syndrome
- clinical finding
- what layer is destroyed?
- sloughing of skin with erythematous rash and fever.
- epidermolysis of stratum granulosum
- S. Aureus exfoliative toxins A and B
varicella
- how does rash present?
- how does infection spread
‘chickenpox’
- rash progresses from macules to vesicles to pustules (all stages simultaneously present, very characteristic)
- infection spread respiratory route, 2 week incubation
cellulitis:
- common risk factors
- what should you worry about its progression?
- recent surgery, trauma, insect bite
- can progress to necrotizing fasciitis (anaerobic flesh eating bacteria)
Condyloma accuminatum:
- common types
- high risk types
- common: HPV 6, 11 (90% of all)
- high risk to cancer: 16, 18, 31, 33 (think jets)
what is it?
- red, tender swollen rash with fever
- presence of crepitus
- necrotizing fasciitis
- crepitus from CO2 production of anaerobic flesh eating bacteria
