Derm Flashcards
What does the keratin layer consist of
keratinocytes -> corneocytes which are then shed off
what is included in the keratin layer include
involucrin, filaggrin, keratin
filaggrin is what
skin barrier gene - filament aggregating protein
what do keratinocytes do
sense pathogens and mediate immune system
produce AMPs, cytokines, chemokines
T cells in epidermis T cells in dermis
CD8 in epidermis CD4 and CD8 in dermis CD4 - Th1 - psoriasis Th2 - atopic dermis Th17 - psoriasis, atopic derm
two types of dendritic cells
dendritic DCs - AG presentation and secrete chemo and cytokines plasmacytoid DC (pDC) releases IFM gamma and is found in diseased skin
chromosome 6 class 1 chromosome 6 class 2
class 1 - present on all cells, presents to CD8 cells, endogenous AG Class 2 - present on only APCs, presents to D4 cells, exogenous AG
immunologically mediated drug reactions - allergic or non allergic - dose dependant or not?
non immunologically mediated drug reactions - allergic or non allergic - dose dependant or not?
allergic. not dose dependant
non allergic, can be dose dependent
types(4) of allergic drug reactions
type 1 - direct - urticaria
type 2 - cytotoxic - phemphigoid/phemphigous
type 3 - immune complex mediated - purpura/rash
type 4 - T cell mediated
AGEP
SJS
TEN
DRESS
acute generalised exanthematous pustules - rare
steven johnson syndrome - minor form of toxic epidermal necrolysis
TEN - >30% of epidermal detachment
DRESS - drug reaction with eosinophilia and systemic symptoms
clingfilm helps what
topical drug absorption
investigation for PCT
woods lamp
drug causes of bullous pemphigoid
furosemide, ACEI, penicillin
linear IgA disease drug cause
vancomycin
fixed drug eruption causes
tetracycline, doxycycline, paracetamol, NSAIDs, carbamazapene
causes of itch
pruriceptive - something on skin - asthma
neuropathic - damage to CNS fibres - shingles
neurogenic - no damage to CNS fibres but affect on them - thyroid disease, bile duct disease, liver disease
psychogenic
Type 1 allergy - how can you catch it
stages
investigation
skin contact, injection, ingestion, inhalation
urticaria, angiooedema, asthma/wheezing, anaphylaxis
skin prick if negative - challenge test
Type 4 allergy - how
ix
airborne, skin contact, injection
patch testing - 48 hours then check after 96 hours
psoriasis phototherapy treatment
narrowband UVB and PUVA
what do retinoids do
decrease skin turnover
open comedones
closed comedones
open - blackheads
closed - whiteheads
demadox mite
rosacea
pompholyx eczema
spongiotic vesicles
Tuberose sclerosis - autosomal what
symptoms/signs
dominant
infantile seizures, ash leaf macule, depigmented macule, preiungual fibromas, facial angiofibromas, haemartomas, bone cysts, shagreen patches, enamel pitting
Epidermolysis bullosa types
simplex - epidermis
junctional
dystrophic - dermis
cafe au lait macules
asymp coffee colours flat macule
1-2 are normal
>5 - NF?
NF1
cafe au lait, neurofibromas (soft neural tumours), plexiform neuroma, axillary or inguinal freckling, 2 or more lisch nodules, bony lesions
what do you need derm protection for
group a strep
MRSA
scabies
what is acicilovir an analogue of
guanine
what is the melanocyte: basal keratinocyte ratio
1:5 - 1:10
breslow - how is it measured
melanoma - 5 year survival
from granular layer to deepest point of invasion
different skin types
type 1 always burns, never tans 2 usually burns, can tans 3 can burn, usually tans 4 never burns, always tans 5 brown 6 black
what does a childhood skin burn lead to
a 4x increased likelyhoood of melanoma
what are the three genetic conditions that lead to an increase risk for skin cancer
xeroderma pigmentosum
albinism
nevoid basal cell carcinoma (gorlins syndrome)
what is xeroderma pigmentosum
median age onset
defect in what
photosensitivity, skin cancer on UV exposed sites
8
one of 7 nucleotides
neurological degeneration
what autosomal is gorlins syndrome
dominant
what UV is more damaging than the other
UVC most
UVB
UVA least damaging
what type of melanin is better at absorbing UV light
eumelanin is better than phaemelanin
layers of SCALP
skin connective tissue aponeurosis loose connective tissue periosteum
Functions of the skin
thermoregulation, immune, UV protection, endocrine function (UV -> vit D), sensory, barrier, fluid and electrolyte balance
what kind of epithelium does skin have
stratified keratinising squamous epithelium
what type of collagen is in the dermis
what are the 2 layers of the dermis
type 1 and 2
papillary - thin and beneath epidermis
reticular - thicker bundles of type 1 collagen - contained appendages
inflame skin diseases (4)
spongiotic - intraepidermal oedema - eczema
psoriaform - elongation of rate ridges - psoriasis
lichenoid - basal layer damage - lichen planus
vesicolubullous - blistering - pemphigoid
immunflurescnce of bullous pemphigoid shows what
linear IgA
what AB is in derm herpeitform and what HLA
IgA AB target is gliadin
HLA DQ2 haplotype
dome shaped vascular papule
spitz naeuvus
phytotoxic drug reactions: amiodarone thiazides CCBs psoralen and UV halo dixic acid
immediate prickling with delayed erythema
exaggerated sunburn
exposed telengectasia
delayed (3-5days) erythema and pigmentation
increased skin fragility
What happens in UV induced immunosuppression
dendritic cells lose the ability to present antigens
T cells switch from helper to suppressor
what antibodies does pemphigoid and phemphigois have
goid hemidesmosome ABs
gous desmoglein 3 (more serious)
HSV 16+18
6+11
1-4
cervical cancer
genital warts
warts/verucas
gardisil vaccination
cervarix vaccination
16, 18, 6 +11
only 16 +18 - only cervical cancer
what is arthus reaction
skin testing testing in type 3 hypersensitivity
slower than type 1 but faster than type 4
what are gene changed in tuberose sclerosis and what inhibitor partially corrects it
TSC1 or TSC2
MTOR inhibitors
what is NF1 responsible for
switching off cell cycle
what are auispitz signs
in psoriasis
bleeding sports where psoriatic scales have been scraped off
what is the signature DNA mutation in UV light
pyrimidine dimer mutation
list the precursors of SSC
and the treatment
bowens
actinic keratosis
viral - HPV
cryotherapy, sola raze, 5 FV, imiquiomod, resurfacing
Treatment for SCC and BCC
surgery
5% imiquimod cream
ulcer that has a shallow edge and is around the malleolus
high cliff like edges and that is punched out and is on pressure points
venous
arterial
non adherent dressing for venus ulcers
absorption - hydrocollides
anti bacterial - silver nitrate/manuka honey
where is latina melanoma derived from and where does it occur
lentigo maligna
chronically sun damaged skin
pigmented lesions on an elderly persons palms/soles/nails
pigment extends into his nails
acralantigous melanoma
what does an amelanotic melanoma look like
decreased or no pigment
what may lead to a dermatofibroma and what do they look like
insect bites
firm, increased pigment around rim, deep (dermal), brown/grey
why do naevi happen
due to melanocytes that have failed to migrate or unigrate in utero
peripheral halo of depigmentation and overrun by lymphocytes
halo naevi
dermal naevi. blue
blue naevus
large spindle and or epithelial cells
spitz naevus
plaque - stuck on appearance - greasy - brown/black - on trunk
what is it and the cause
seborreohiec keratosis
bengin proliferation of epidermal keratinocytes
bulli that burst to form erosions
bulli that burst to form raw marks
pemphigoid
pemphigus
bulli either in one area or widespread over his trunk and prox limbs
bulli on scalp, axilla and groin
bulli on elbows and knees symmetrical and they itch
pemphigoid
pemphigus
dermatitis herpetiformis
itchy rash in fingerwebs, wrists and genital area
scabies
thick crusted skin in elderly or immunocompromised
Norwegian scabies
red moist skin with ragged peeling edge and papule/pustules/erythema on the edges
candida
where does candida intertigro occur
in skin folds where area is warm and moist
bulls eye target lesions
erythema multiforme
child
fresh firm umbiilcated nod that is 1-2 mm in dm
mallocusum contagious
can be sexually transmitted
self limiting
liquid nitrogen
blistering rash at the back of the mouth
herpengioma
enterocci
swab. stool sample
self limiting
what is hand foot and mouth disease caused by
enterovirus
primary syphilis secondary tertiary ix rx
painless ulcer rash all over body - snail track ulcers CNS, CVS etc. blood test, swab of ulcer injections of penicillin
