Dermatology Flashcards
flat spot less than 1cm (non-palpable, just visible)
ex:freckles, tattoos
macule
flat spot>1cm
ex:port wine stain
patch
solid, elevated lesion
papule
same as papule but >!cm and flat-topped
ex: psoriasis
plaque
palpable, solid lesion >1cm, not flat-topped
ex: small lipoma
erythema nodosum
nodule
elevated circumscribed lesion
vesicle
same as vesicle but >5mm (large blister)
ex. contact dermatitis, pemphigus
bulla
Itchy, transiently edematous area
ex:allergic reaction
wheal
erysipelas
upper dermis
superficial lymphatics
may appear raised with clear line of demarcation
cellulitis
deeper dermis
subcutaneous fat
risk factors for erysipelas and cellulitis
chronic skin problems diabetes mellitus chronic swelling of LE IV drug use immunocompromiased state penetration of skin (surgery/trauma) previous cellulitis
Diagnosis and labs in cellulitis and erysipelas
Clinical diagnosis
increased WBC count, ESR, CRP
blood cx
Common organisms in cellulitis
- beta- hemolytic strep
s. pyogenes, group B strep - s. aureus common in abscesses
How do we treat cellulitis
non-purulent cellulitis:
PO- dicloxacillin
cephalexin
clindamycin
IV- cefazolin
nafcillin
clindamycin
purulent cellulitis: PO- clindamycin TMP-SMX Doxycycline Linezolid
IV abx-
vancomycin
Skin abscesses
collection of pus within dermis and deeper skin tissues
Furuncle (boil):
infection of hair follicle
purulent material extends through dermis into subQ tissue
often drains spontaneously
Carbuncle
coalescence of several inflamed follicles
Diagnosis of abcess, furuncle, carbuncle
clinical
culture is indicated for bacterial idenfication
-s.aureus in 75% of cases
Treatment of skin abscess
let the pus out
if large,
incision and drainage
for patients at risk of endocarditis: vancomycin 1hr prior to incision and drainage
oral: clindamycin, tmp-smx, doxycycline, linezolid
IV: vancomycin
antibiotics are often unsuccessful because you need to get the pus out
Hidradenitis suppurative
recurrent infection/occlusion of apocrine glands
MC site: axilla
Tx:
-general measures: avoid skin trauma, gentle cleansing, smoking cessation, weight loss
-mild disease: topical clindamycin daily, punch debridement
second line: clindamycin with rifampin
severe disease: oral doxycycline or minocycline, more invasive surgical debridement
-alternative treatments: intralesional steroids, anti-adrenergic drugs, TNFa inhibitors, oral retinoids
necrotizing fasciitis
infection spreading along fascial plane
polymicrobial- anaerobes, gram +, gram -
GAS
often in the setting of some systemic disease
H and P:
unexplained, excrutiating pain in the absence of or beyond areas of cellulitis
bulla, necrosis, crepitus
Dx: surgical exploration is the only way to definitively diagnose, as well as to treat
rapidly worsening cellulitis with severe pain
Xray: crepitus, subcutaneous air can be seen with plain film on an xray
Fournier gangrene
perineal cellulitis with abrupt onset and rapid spread
this is a urological emergency
What is the general treatment for necrotizing fasciitis?
immediate aggressive surgical debridement
abx:
1. carbapenem (imipenem or meropenem)
or beta-lactam plus beta-lactamase inhibitor (piperacillin +tazobactam)
PLUS
2. clindamycin
PLUS
3. vancomycin
Gangrene
significant amounts of body tissue necrosis
a chronic condition compared with necrotizing fasciitis
dry gangrene (chronic, distal, severe ischemia) treat with revascularization or allow auto-amputation
wet gangrene: bacterial infection in moist tissue: debridement, possible amputation
gas gangrene: caused by clostridium perfringens
- debridement
- hyperbaric oxygen
- antibiotics