derm Flashcards
layers of epidermis?
surface to base (Californians Like Girls in String Bikinis): Corneum (keratin) Lucidum Granulosum Spinosum (desmosomes) Basale (stem cells)
zonula occludens?
= tight junction
apical side of epithelial cell
claudins and occludins
prevents paracellular solute movement
zonula adherens?
= adherens junction
below zonula occludens
connects actin cytoskeletons of adjacent cells with cadherins (Ca dependent)
** loss of E-cadherin –> metastasis
macula adherens?
= desmosomes
below zonula adherens
keratin interactions –> structural support
** autoAbs –> pemphigus vulgaris
epithelial cell gap junctions?
made up of connexons
allow communication
epithelial cell integrins?
at basolateral surface
proteins that bind to collagen and laminin in basement membrane
hemidesmosomes?
at basolateral surface
connect keratin of basal cells to basement membrane
** autoAbs –> bullous pemphigoid
increased thickness of stratum corneum?
hyperkeratosis
seen in psoriasis, calluses
hyperkeratosis with retention of nuclei in stratum corneum?
parakeratosis
seen in psoriasis
epidermal accumulation of edematous fluid in intercellular spaces?
spongiosis
seen in eczematous dermatitis
separation of epidermal cells?
acantholysis
seen in pemphigus vulgaris
epidermal hyperplasia (increased stratum spinosum)?
acanthosis
decreased melanin production, normal melanocyte number?
albinism
defect in tyrosinase activity or tyrosine transport; or failure of neural crest cell migration in development
** increased risk of skin cancer
preggo with hyperpigmented areas on face?
melasma (chloasma)
assoc with preg or OCP use
autoimmune destruction of melanocytes?
vitiligo
melanocytic nevus?
common mole
** intradermal nevus: papular; junctional nevus: flat
epidermal changes in psoriasis?
increased stratum spinosum and stratum corneum
decreased stratum granulosum
rhinophyma?
bulbous deformation of nose
from chronic inflammatory changes of rosacea
sudden appearance of multiple seborrheic keratoses?
Leser Trelat sign = sign of underlying malignancy
- GI, lymphoid
honey colored crusting?
impetigo
S aureus or S pyogenes
(bullous usually S aureus)
well-defined demarcation b/w infected and normal skin?
erysipelas
upper dermis and superficial lymphatic involvement
S pyogenes
MC organism in skin abscess?
MRSA
bullae, purple skin, crepitus?
nec fasc
anaerobes or S pyogenes
fever and generalized erythematous rash with sloughing?
staph scalded skin
** exotoxin destroys keratinocyte attachments in stratum granulosum ONLY
white painless NON-scrapeable tongue plaques?
hairy leukoplakia
EBV
flaccid intraepidermal bullae, oral involvement, Nikolsky +?
pemphigus vulgaris - potentially fatal
IgG Abs to desmoglein (anti-desmosome)
immunofluorescence: Abs in reticular pattern around epidermal cells
** bullae caused by acantholysis
tense blisters, no oral involvement, Nikolsky -?
bullous pemphigoid - not as bad as vulgaris
IgG Abs to hemidesmosomes
immunofluorescence: Abs in linear pattern at epidermal/dermal junction
** blisters contain eosinophils
pruritic papules, vesicles, bullae; often at elbows?
dermatitis herpetiformis
IgA deposits at tips of dermal papillae
assoc with celiac
multiple lesion types, including target lesions?
erythema multiforme infections: mycoplasma, HSV drugs: sulfa, beta lactams, phenytoin cancer autoimmune dz
SJS/SJS-TEN/TEN?
SJS < 10% BSA
SJS-TEN: 10-30%
TEN > 30%
small rough red/brown papules/plaques?
actinic keratosis
premalignant –> squamous cell ca
caused by sun exposure
painful lesions on anterior shins?
erythema nodosum
subQ fat lesions
** assoc with sarcoid, coccidio, histo, TB, strep, leprosy, Crohn
pruritic, purple, polygonal, planar papules and plaques?
lichen planus
mucosal involvement: Wickham striae (white lines)
sawtooth lymphocytic infiltrate at dermal-epidermal junction
** assoc with HCV
UVA vs UVB?
UVA –> tanning, photoaging
UVB –> sunburn
UV radiation –> DNA mutation, keratinocyte apoptosis
pink pearly nodule, rolled borders, central crusting/ulceration?
basal cell carcinoma
MC skin cancer
locally invasive, rare mets
** palisading nuclei
ulcerative red lesions with frequent scale; sun-exposed areas?
squamous cell carcinoma
2nd MC skin cancer
locally invasive, LN spread possible, rare mets
- keratin pearls on histo
- assoc with arsenic exposure
melanoma marker?
S-100
melanoma mutation?
BRAF kinase activating mutation
** BRAF V600E - can try vemurafenib (BRAF kinase inhibitor)