Derm Flashcards
erythema multiforme looks like
target lesions with erythema
erythema multiforme associated with
HSV
drug eruptions
mycoplasma pneumoniae
herpangina
virus causing painful mouth blisters
common in kids
coxsackie & echovirus
resolves itself
orf
parapoxvirus
caused by handling infected sheep
firm, fleshy nodule on hand commonly that can be red/blue
-> pustule -> crust over
cllears itself in 3-6weeks
Primary syphilis infection
chancre (painless ulcer)
local non-tender lymphadenopathy
secondary syphilis infection
systemic symptoms: fevers, lymphadenopathy
rash on trunk, palms and soles
buccal ‘snail track’ ulcers (30%)
condylomata lata (painless, warty lesions on the genitalia )
tertiary syphilis infection
gummas (granulomatous lesions of the skin and bones)
ascending aortic aneurysms
general paralysis of the insane
tabes dorsalis
Argyll-Robertson pupil
Investigations for syphilis
bloods
swab chancre for PCR
treponoma pallidum
syphilis
borrelia burgdorferi
lyme disease
early + late signs lyme disease
early: erythema migrans
late: heart block, nerve palsies, arthritis
necrotising fasciitis types
type 1 is caused by mixed anaerobes and aerobes (often occurs post-surgery in diabetics). This is the most common type
type 2 is caused by Streptococcus pyogenes
tuberous sclerosis non-derm signs
epilepsy
tuberous sclerosis tumours
periungal fibromas
facial angiofibromas
hamartomas aka angiomyolipomas
bone cysts
tuberous sclerosis skin
ash-leaf macules
shagreen patches
erythema infectiosum
slapped cheek, parvovirus b19
investigation for parvovirus b19
antibody test for parvovirus b19 IgM
NF1 tumours & skin
cafe-au-lait macuels
neurofibromas
azillary or inguinal freckling
optic glioma
lisch nodules
NF1 non-derm sign
learning difficulty
superficial melanoma site
trunk and limbs
acral/mucosal lentiginous melanoma site
acral: soles of feet, hands and nailbeds
lentigo maligna melanoma sites
sun damaged face/scalp/neck
nodular melanoma sites
anywhere but often trunk
most common sites for melanoma mets
lung
brain
liver
melanoma types from most common to least
superficial spreading
nodular
lentigno maligna
acral
major criteria melanoma
change in size
change in shape
change in colour
Secondary features (minor criteria) melanoma
Secondary features (minor criteria)
Diameter >= 7mm
Inflammation
Oozing or bleeding
Altered sensation
margins for excision if breslow thickness 0-1mm thick
1cm
margins for excision if breslow thickness 1-2mm thick
1-2cm
margins for excision if breslow thickness 2-4mm thick
2-3cm
margins for excision if breslow thickness >4mm thick
3cm
5 year melanoma survival if breslow thickness < 0.75 mm
95-100%
5 year melanoma survival if breslow thickness >4mm
50%
BCC what skin layer
keratinocytes in basal layer of epidermis
SCC what skin layer
keratinocytes in suprabasal layers
keratoacanthama looks like and may be confused with
looks like fast growing papule with keratin plug
may be confused with SCC
Bowen’s disease
RED SCALY patches
often 10-15 mm in size
slow-growing
often occur on sun-exposed areas such as the head (e.g. temples) and neck, lower limbs
Actinic keratosis
small, CRUSTY or scaly, lesions
may be pink, red, brown or the same colour as the skin
typically on sun-exposed areas e.g. temples of head
multiple lesions may be present
SCC excision margins
if <20mm - excision margin 4mm
If >20mm - excision margin 6mm
rodent ulcers
BCC
Scabies treatment
permethrin 5% is first-line
malathion 0.5% is second-line
everyone in household
do full body TWICE, 7 days apart
pompholyx
hands and feet
worse in sweaty and hot
small blisters
very itchy
management: emollients and topical steroids
Dermatitis in acral, peri-orificial and perianal distribution
→ ?zinc deficiency
SCC poorer prognosis if
diameter >20mm and depth >4mm
high-risk patients and in cosmetically important sites treatment for scc?
Mohs
SCC in situ AKA
Bowen’s disease
SCC in situ AKA
Bowen’s disease
Positive non-treponemal test + positive treponemal test
consistent with active syphilis infection
consistent with active syphilis infection
Positive non-treponemal test + negative treponemal test
consistent with a false-positive syphilis result e.g. due to pregnancy or SLE
Negative non-treponemal test + positive treponemal test
consistent with successfully treated syphilis
RPR and VDRL are what type of syphilis tests
non-treponemal
Syphilis management
IM Benzathine penicillin
OR doxy if pen allergic
then monitor non-treponemal levels: should decrease 4fold
Fournier’s gangrene
nec fasc of the perineum
which DM drug is most associated with fourniers gangrene
SGLT2 i
pain, swelling, erythema at the affected site
often presents as rapidly worsening cellulitis with pain out of keeping with physical features
extremely tender over infected tissue with hypoaesthesia to light touch
skin necrosis and crepitus/gas gangrene are late signs
necrotising fasciitis
