derm Flashcards
eczema pathophysiology
null mutations in filaggrin gene
> epidermal permeability
Th2 inflammatory response
topical steroids for eczema
mild- hydrocort
mod- clobetasone butyrate/eumovate
potent- betamethansone/betnovate
v potent- clobetasol propionate/dermovate
specialist treatment for eczema
calcineurin inhib- tacrolimus/pimecrolimus
UVB or PUVA
ciclosporin or azathioprine
alitretinoin (hand dermatitis)
BCC treatment and types
surgical excision, routine referral to derm
imiquimod for small low risk BCC
vismodegib for advanced/metastatic
nodular (most common) pearly raised edges, telangiectasia, may ulcerate
morphoeic (sclerosing) mostly on face, waxy
pigmented
superficial (plaques) most common in younger adults
mixed basosquamous, more aggressive
7 point checklist for malignant melanoma
major (2 points):
change in size
irregular shape/border
irregular colour
minor (1 point):
diameter > 7mm
inflammation
oozing/crusting
change in sensation
refer if 3 points
bullous pemphigoid antibodies
BP antigen II BP180
BP antigen I BP230
IgG
inflam cells release proteases
> degrade hemidesmosomal proteins connecting basal cells to lamina lucida
pemphigoid treatment
dx:
skin biopsy for light microscopy
skin biopsy for direct immunofluorescence
indirect immunofluorescence on serum
topical steroids for local disease
systemic for widespread
azathioprine/ciclosporin if steroid resistant
usually self limiting within months-years
pemphigoid risk factors
previous chronic inflam skin diseases
furosemide, abx, NSAIDs
PD, epilepsy, dementia
cellulitis organisms
staph and strep pyogenes
strep pneum, haem infl, gram neg, anaerobes- injury, burns
pseudomonas aeruginosa- hot tubs, sponges, nail puncture
vibrio vulnificus- salt water
aeromonas hydrophila- fresh water
erysipelothrix- butcher, vet, fish handler
myobacterium marinum- aquarium
pasteurella, capnocytophaga- cat/dog bite
eikenella- human bite
streptobacillus moniliformis- rodent bite
eron classification of cellulitis
1: no systemic symptoms or comorbidities
2: systemically unwell or comorbidity
3: severe systemic symptoms (tachy/hypotensive) or unstable comorbidities
4. severe infection e.g. nec fasc
cellulitis admission criteria
severe infection or systemic symptoms
infection close to eyes or nose
might be caused by uncommon organism
not responding to oral tx
lymphangitis
cellulitis treatment
fluclox
clari or doxy if pen allergic
erythromycin if pregnant
coamox or clari +metro if near eyes
amox if lymphoedema
abstinence and testing after chlamydia
abstain for 7 days after treatment with azithromycin
re-test after 3-6 months
test of cure only for pregnant people (3 weeks after treatment)
dermatitis herpetiformis biopsy
microabscessses containing neutrophils and eosinophils
granular IgA deposits
treating dermatitis herpetiformis
oral dapson
sulfapyridine
rituximab
steroids
causes of erythema multiforme
HSV, HIV, hepB, EBV
mumps
mycoplasma
psittacosis
rickettsia
barbiturates, penicillins, sulfonamides
SLE, polyarteritis nodosa, sarcoid
causes of erythema nodosum
strep, salmonella, campylobacter, tb
sarcoid, UC, crohns
lymphoma, leukaemia
penicillin, tetracycline, OCP
pregnancy
erythroderma risk factors
eczema, psoriasis
lymphoma
sezary syndrome
drug reactions
blistering conditions
pityriasis rubra pilaris
HIV
other malignancies
erythroderma dx and tx
raised IgE
tx:
urgent admission
IV fluids
emollients, wet dressings
topical steroids
warm room to prevent hypothermia
erythroderma
> 90% skin inflammation and shedding
what drugs can cause alopecia?
retinoids
anticoagulants
anti mitotics
OCP
carbimazole
thiouracil
lithium
causes of scarring alopecia
ichthyosis
TB, syphilis
burns, RTx
kerion, tinea capitis
lichen planus
lupus, sarcoid, pemphigoid
morphoea
alopecia areata associations
nail dystrophy
cataracts
vitiligo
autoimmune thyroid disease
pernicious anaemia
addisons
anagen/telogen effluvium
anagen effluvium:
hair loss during anagen stage
pointed tip
alopecia areata, CTX, retinoids
telogen effluvium
hair loss when increased number of hairs enter telogen stage and shed
postpartum, trauma, illness, stress, weight loss
types of hypersensitivity reaction
1:
IgE, mast cells, basophils
atopy, anaphylaxis, contact dermatitis
2: antibody dependent
IgG
drug induced haemolysis, acute transfusion, goodpastures
3: immune complex
serum sickness, SLE, post strep GN
4: delayed cell mediated
helper and cytotoxic T cells
contact dermatitis, BCG
lichen planus treatment
topical steroids
tacrolimus ointment
oral steroids if widespread
MTX for hair and nails
UVB second line
types of melanoma
superficial spreading- irregularly pigmented macule/plaque
nodular- often rapidly growing
lentigo- irregularly pigmented macule, older patients and slowly expanding
acral- pals, soles, toenails
amelanotic
melanoma treatment
CTX for metastatic unresectable
vemurafenib for v-raf murine sarcoma BRAF mutation
ipilimumab
resect with 2mm margin
molluscum contagiosum treatment
not normally indicated
hydrogen peroxide cream or iodine
pdophyllotoxin
topical salicylic acid
cantharidin
strawberry naevi
treat if it obstructs vital structures
> propranolol and prednisolone
Kasaback Merritt- low platelets, enlarging haemangioma, haemolysis, consumption coagulopathy
PHACE- posterior fossa defects, arterial anomalies, cardiac defects, eye anomalies
sebaceous naevi
present at birth on scalp/face
can undergo neoplastic change after puberty
neurocutaneous melanosis
melanocytic naevi
EEG abnormalities
raised ICP, hydrocephalus, SOL
neurofibromatosis
1:
NF1 chromo 17, auto dom
neurofibromas, cafe au lait
freckles
dermatofibromas
lisch nodules
2:
NF2, chr 22, auto dom or de novo
b/l acoustic neuromas
meningiomas, glial tumours
fewer cafe au lait spots
reduced life expectancy
schwannomatosis:
tender cutaneous schwannomas without vestibular neuroma
high tumour load
pemphigus HLA alleles and antibodies
paraneoplastic: HLA DR4, HLA DQ1
vulgaris: HLA DRB1
IgG mediated
vulgaris: desmoglein 1 and 3 antibodies
foliaceus: desmoglein 1 antibodies
paraneoplastic pemphigus compared to pemphigus vulgaris
nikolsky negative
no scalp pruritus
no dysphagia
background malignancy
drug causes of photosensitivity
doxy, fluoroquinolones, voriconazole
chlorpromazine, prochlorperazine
furosemide, thiazires
sulfonamides, amiodarone, promethazine, NSAIDs, metformin, vemurafenib
pityriasis versicolour cause
malassezia
vitiligo treatment
topical steroid or pimecrolimus
cause of plantar warts
HPV 1, 2, 4, 27, 57
psoriasis pathophysiology
expansion of Th1, Th17, Th22
> release cytokines IL 17, !L 22, TNF a
what drugs might exacerbate psoriais?
beta blockers
lithium
antimalarials
interferon
withdrawal of oral steroids
systemic treatment for psoriasis
MTX (need to monitor P3NP)
ciclosporin (first line if acute control is needed or palmar pustular)
retinoids
etanercerpt, adalimumab, infliximab (TNFa inhib)
ustekinumab (IL 12 and 23 antibody)
conditions associated with pyoderma gangrenosum
UC, crohns
RA, ank spond
chronic hepatitis, PBC, sclerosing cholangitis
leukaemia, lymphoma, myeloproliferative
DM, thyroid, sarcoid, granulomatosis w/ polyangiitis
rosacea treatment
mild/mod: topical metro or azelaic acid
mod/severe: bromonidine (for erythema alone), PO abx
refer to derm for persistent flushing and telangiectasia for beta blockers, clonidine, isotretinoin
SCC referral
2ww
low risk of malignancy but early treatment prevents extensive treatment
lesions related to SCC
keratoacanthoma (excision)
bowens (cryo, excision or 5FU)
actinic keratoses (cryo, excision, 5FU, diclofenac or imiquimod cream)
causes of SJS and TEN
allopurinol
cephalosporin
NSAIDs
phenytoin
carbamazepine
sulfasalazine
sertraline
antivirals
HSV, resp infections, mumps
EBV, coxsackie, influenza
HLA B1502, HLA B1508 increases risk
SJS vs TEN
SJS: < 10% total body surface area skin detachment, widespread macules or targets
overlap: 10-30% skin detachment with widespread macules or targets
TEN: > 30% body surface area skin detachment with macules or targets
OR > 10% with large epidermal sheets and no purpuric macules
