DERM: Pustules, Vesicles & Bullae I & II Flashcards
acne
- pathogenesis
- presentation
- treatment
- pathogenesis: cutibacterium acnes hydrolyze fats (sebum) into fatty acids -> greasy plug at follicular orifice made of keratin + sebum + bacteria
- presentation: on face, upper chest and back
- open comedo (blackhead)
- closed comedo (whitehead)
- pustules, papules
candidiasis
- pathogenesis
- demographics
- presentation
- diagnosis
- treatment
- pathogenesis: candida albicans (gram + yeast) colonizes skin + mucosa + GI, leading to formation of biofilms
- demographics: I/C - AIDS, DM, steroids, elderly
- presentation: beefy / dark-red plaques with satellite lesions on areas that are
- moist, occluded (like intertriginous)
- cutaneous
- diagnosis:
- 10% KOH wet mount: pseudohyphae + budding yeast cells (spores)
- + germ tube test
- treatment: anti-fungals
candidias
+ germ tube test
impetigo contanegeousa
- pathogenesis
- demographics
- presentation
- complications
- pathogenesis: s. pyogenes / s. aureus
- demographics: children (2-5 yeares)
- presentation: non-bullous vesicles that rupture into -> purulent erosions with honey-colored thick crusts
- complications: post-streptococcal glomerulonephritis
- diagnosis: rising anti-DNase B-titer / anti-streptolysins (titer)
- catalase negative = s. pyognees (GAS)
- catalase positive = s. aureus
how is bullous impetigo different than impentigo contagiousum
- always d/t s. aureus - phase type 71 specifically (impetigo contagiousum d/t s. pyo > staph)
- is a flacid bullae (impetigo contagiousum arises from non-bullous pustules)
what is the major complication of impetigo?
what is the role of early tx in this risk?
post-streptococcal glomerulonephritis
early tx does NOT reduce risk of developing this PSGN
ecthyma
- pathogenesis
- demographics
- presentation
- comlications
- s. pyogenes > s. aureus causes purulent ulcers
- demographics: I/C
- presentation:
-
punched out ulcers that are
- painful
- shallow
- have erythematous border
- -> form thick, brown black crusts
- fever
-
punched out ulcers that are
folliculitis
- pathogenesis
- presentation
- diagnosis
- comlications
- pathogenesis: inflammation of any part of the hair follicle, typically d/t:
- s. aureus: typical
- pseudomonas aeruginosa: gram - folliculitis
- malassezia furfur: fungal folliculitis
- presentation: pustules at hair follicles, commonly in areasof terminal hair growth
- diagnosis: clinical picture typically sufficient
- but might confirm etiology if chronic: wood’s lamp:
- psuedomonas folliculitis: flouresce green
- malassezia folliculitis: flourescent blueish-white
- but might confirm etiology if chronic: wood’s lamp:
wood’s lamp can differentate between what two etiological causes of folliculitis?
what will it show?
- psuedomonas: green
- malassezia:blueish-white
kerion
- pathogenesis
- presentation
- diagnosis
- therapy
- pathogenesis: dermatophytes (fungus) -> induce type IV sensitivity reaction
- presentation: furuncle / carbuncle like like lesion that is
- painful
- rounded
- boggy
- diagnosis: culture demeratophytes sabrouaud dextrose agar (will show growth)
- therapy: griseofulvin
identify pictures & explain significance
shown are the dermatophytes that can cause kerion after application of a 10% KOH exam
hidradenitis suppurativa
- pathogenesis
- demographics
- presentation
- complications
- demographics: polymicrobial flora (mostly anaerobes) -> occlude follicles in areas with many oil and sweat glands
- demographics: more common in obese patients
- presentation: sinus tracts (scars) that
- drain purulent + malodour fluid
- are painful
- are on the axillary / inguinal / peranial skin
curtaneous myiasis
- pathogenesis
- presentation
- treatment
- pathogenesis: infestation by non-contagious fly larvae that burrow into skin leaving wounds. one of the following:
- human bot fly (dermatobia hominus) - most common
- stays for 5-10 weeks
- new world screw worm fly (cochliomyia hominovorax) - most dangerous
- stays for 5-7 days
- blowfly larvae (calliphora)
- stays for 3-9 days
- human bot fly (dermatobia hominus) - most common
- presentation: small red papule that becomes a -> painful furuncle with central pore
- treatment: removing with local anesthetic
what are the causes of cutaneous myiasis and how are they different?
all non infectious flies: differ based on how long they stay burrowed in skin
- human bot fly (dermatobia hominus) - most common: 5-10 weeks*
- screw worm fly (cochliomyia hominovorax) - most dangerous: 5-7 days*
- blowfly larvae (calliphora): 3-9 days
hand, foot & mouth disease
- pathogenesis
- demographics
- presentation
- complications
- pathogenesis: cocksackie A16 > enteroviruse 71 (echoviruses) infiltrates -> keratinocyte apopotosis
- demographics: children < 10 yrs
- presentation:
- painful vesicles on tongue, +
- macular rash - _of elliptical, gray lesion_s - restricted to hands & feet
- complications:
- onchyomadesis: shedding of nails after recovering
- fatality: rare, but tends to be associated with enterovirus 71
list each member of the herpesvirus family abd which disease it is associated with
- HHV-1: HSV-1 - oral herpes
- HHV-2: HSV-2 - genital herpes
- HHV-3: varicella zoster: chickenpox, shingles
- HHV-4: mononucleosis, gionetii-crost
- HHV-5: CMV
HHV-6: roseola - HHV-7: pitryiasis rosea
- HHV-8: kaposi-sarcoma
herpes simplex virus
- pathogenesis
- presentation
- diagnosis
- complication:
- treatment:
- pathogenesis: HSV-1 or HSV-2 induce formation of epithelial multinucleated giant cells then -> invade sensory nerve ends to trigminal ganglion to establish latencey
- presentation: grouped, painful vesicles on an erythematous plaque that rupture to form ulcers with yellow crust
- HSV-1: oral mucosa
- HSV-2: genitals
- herpes gladioatorum (HSV-1): face, neck & arms (wrestlers)
- hepertic whitlow (HSV-1/2): on hand, esp at distal phalanx (healthcare workers + children sucking thumbs)
- diagnosis: + Tzanck test: Cowdry Type A bodies
- complications: congtenital transmission (TORCH dz) - most likely during delivery
- treatment: acycylovir
herpetic whitlow (HSV-1 or HSV-2)
vesicles on erythematous plaque - on distal phalanx
commonly in _health-care worker_s or children sucking thumbs
tzanck test: 3 syncitita with cowdry bodies
indicative of HSV-1 / HSV-2 of varicella-zoster (HHV-3)
chickenpox (varicella)
- pathogenesis
- demographics
- presentation
- diagnosis
- complications
- prevention
- pathogenesis: HHV-3 induces ballooning degernation of epithelial cells (forms clear vesicle) and epithelial multinucleated giant cells (forms erythematous base)
- demographics: unvaccinated individuals
- prseentation: vesicles on an erythematous base (“dewdrops on a rash”) that rupture -> form crust
- painless but pruritic
- appear in” crops”
- have centrifugal distribution: go from trunk -> outward to extremities
- diagnosis: + Tzacnk test - multinucleated giant cells
- complications:
- congenital varicella syndrome - transmission to fetus (TORCH dz)
- reyes syndrome: encephalitis + fatty liver disease
- herpez zoster: latent reactivation
- prevention: varivax (live attenuated) - recommended for children & unvaxed, non-pregnant adults
herpes zoster
- pathogenesis
- presentation
- complications
- prevention
aka shingles
- pathogenesis: reactivation of HHV-3 from VZV -> affecting a single sensory dermatome on trunk
- presentation: vesicles on a red, erythematous base (just like VZV) that rupture -> crust over, that are:
- on the trunk in _single dermatom_e
- approach but DONT CROSS midline
-
preceded by paresthesia & disabling pain
- pain that resembles “rib fracture or myocardial infarction”
- diagnosis: + Tzank test
- complications: opthalmic zoster (via V1)
- __indicated by hutchinson’s nose (refer to opthalmologist)
- prevention: Shingrex vaccine - recommended for individuals > 50
disseminated vibrio vulnificus infection
- pathogenesis
- presentation
- diagnosis
- complications
- pathogenesis: vibrio vulnificus (a halophillic, flagellated gram - curved rod) is contracted via either
- seafood ingestion (primary septicemia)
- exposure of open wound to contamined sea water
- presentation: systemic symptoms preceed skin presentation
- systemic:
- fever / chills / malaise +/- HYPOtn
- GI - nausea / vomitting / water diarrhea
- skin: painful lesions -> necrosis, sloughing
- systemic:
- diagnosis: thiosulfate-citrate-bile-sucrose (TCBS) agar will show growth, but not fermentation: i.e, will stay a GREEN color
- complications: fatality is must more likely if primary septicemia > wound infection
ricksettsiapox
- pathogenesis
- demographics
- presentation
- treatment
- pathogenesis: ricksettsia - a obligate intracellular pathogen contracted via mite bite from mouse vector
- demographics: more common in urban areas: MORE MICE (vector) in homes
- presentation: eschar lesion / fever + papulovescicle crop
- tender, papular lesion immediately forms at bite site -> forms eschar
- next, a papulovesicular rash crop breaks out anywhere EXCEPT palms or soles
- treatment: doxycycline
molluscum contagiosum
- pathogenesis
- presentation
- diagnosis
- diagnosis: infection by ovoid dsDNA molluscipoxvirus
- presentation: lesions that are
- flesh colored
- dome-shaped
- umbilicated (central depression)
- expresses a cheese-like materal with pressure
- found anywhere EXCEPT palms and soles
- diagnosis: with henderseon-patterson bodies: virus containing kerationcytes; shown with giemsa stain
orf
- pathogenesis
- demographics
- presentation
= echthyma contagiosum
- pathogenesis: orf virus - ovoid dsDNA parapoxvirus - from direct contact with either:
- SHEEP
- GOAT
- demographics: farmers, butchers, veterians
- presentation: seriss of phases at site of abrasian - m/c, on hand:
- tender papule
- target nodule: red center - white middle ring - red halo
- umbilicated pustule
- weeping nodule - white, gray crust
monkeypox
- pathogenesis
- demographics
- presentation
- prevention
- pathogenesis: orthopoxvirus
- demographics: endemic to central and west africa
- presentation: like small-pox + lymphadenopathy
- umcilicated pustules that
- start on face / arms then rapidly descend
- are everywhere INCLUDING palms and soles\
- umcilicated pustules that
- prevention: smallpox vaccine
ecthyma (s. pyogenes)
ulcers that are - punched out with erythematous borders that form thick, brown black crusts
folliculitis - s. aureus, p. aeruginosa, malassezia
kerion (dermatophytes)
furuncle that is - painful, rounded, boggy, suppurative
hidradenitis suppurativa
sinus tracts that are - tender, purulent, malodorous
hand, foot & mouth disease (cocksackie A)
tzacnk test
HSV-1/ HSV-2, or VZV (HHV-3), or HZV (HHV-3)
gonococcemia
thayer martin agar showing gram - diplococci
vibrio vulnificus
gram - rod that is: halophillic (salt loving), flagellated, and curved
vibrio fulnificus
TCBS agar is green - showing growth, but not fermentation
varciella / chickenpox (HHV-3)
vesicles surrounded by red halo (“dew drops on rose petal”) - pruritic, centrifigual distribution: trunk -> extremiies
HZV (HHV-3)
vesicles on a red base - unilateral (doesn’t cross midline), following 1-2 contiguous dermatome on trunk, often preceded with paresthesia & debilitating pain
ovoid dsDNA molluscipoxvirus
molluscum contagiosum, orf, monkeypox
molluscum contiogsum
henderson-patterson bodies: virus filled keratinocytes (“mollusck shaped”
orf / echtyma contagiosum
evolving pustule (here, “target nodule” - red-white-red) on hand, from direct contact with goats / sheep
milkers nodule
presents just like orf: but from contact with cows udders / muzzles
molluscum contagiosum (ovoid dsDNA molluscipoxvirus)
lesion that is - flesh colored, dome shaped, umbilitcated, NOT on palms & soles - can express cheese-like material with pressure
molluscum contagiosum (ovoid dsDNA molluscipoxvirus)
lesion that is - flesh colored, dome shaped, umbilitcated, NOT on palms & soles - can express cheese-like material with pressure
