Epidermal & Dermal Response to Injury Flashcards
why should a gross description of a lesion be submitted with a biopsy
skin biopsies are small (usually 6 mm punch biopsies)
requires adequate description of the gross appearance to achieve a final diagnosis
what are the two main steps of describing dermatologic lesions
- patterns - cell arrangement
- subcategories
what are the subcategories to describe patterns
- character of cell infiltrate
- superficial vs deep
- primary spongiosis
- necrotizing
- ulcerative
- hyperplastic
perivascular dermatitis
inflammation surrounding the vessels of the dermis
how common and how diagnostic is perivascular dermatitis
very common - ALL dermatitis starts as perivascular because cells extravasate from vessels
LEAST diagnostic pattern
what epidermal changes are seen in perivascular dermatitis
- pruritus
- inflammation
- scratching/licking
acute histologic lesions of perivascular dermatitis
- spongiosis
- parakeratosis
- hypogranulosis
chronic histologic lesions of perivascular dermatitis
- compact hyperkeratosis
- hypergranulosis
what does the depth of perivascular dermatitis tell you
superficial only: indicates an outside –> in process
superficial + deep: indicates an inside –> out process
what does type of cell infiltrate tell you about perivascular dermatitis
chronicity
cell type changes over time
what are specific features associated with perivascular dermatitis
- keratinocyte swelling (intracellular edema)
- diffuse superficial epidermal lysis
- diffuse parakeratosis
- keratinocyte apoptosis
what disease process is most consistent with keratinocyte swelling
viral infection
what disease process is most consistent with parakeratosis
metabolic process
cytotoxic interface dermatitis
single cell necrosis or apoptosis of keratinocytes
causes keratinocytes to become VACUOLATED
what are etiologies for cytotoxic interface dermatitis
- autoimmune
- immune-mediated
- viral
- ischemic
cell-rich interface
lichenoid inflammation associated with single cell necrosis
- subepidermal band of inflammatory cells
cell-poor interface
minimal to mild perivascular inflammation
pigmentary incontinence
damage to keratinocytes leading to “drop out” of melanin that gets phagocytized by dermal macrophages
causes leukoderma and leukotrichia
subepidermal clefting
basal cell damage leading to BMZ failure and dermal-epidermal separation
causes ulceration
vasculitis
inflammation of the blood vessels (arteries, veins, small vessels)
what causes vasculitis
infectious
immune mediated
signs of acute vasculitis
erythema
ecchymosis
hemorrhagic macules
palpable purpura
superficial ulcers
necrosis
no blanching on diascopy
diascopy
pressing a glass slide against redness to determine if true color change or vasodilation
histology of vasculitis
inflammatory cells migrating through vessel wall with NECROSIS of the wall
target of cell attack is the vascular wall
cell rich vasculitis
intact and degenerate inflammatory cells within wall
various degrees of degenerative change
cell poor vasculitis
degenerative changes of the vascular walls
lack of inflammation
intraepidermal vesicular/pustular dermatitis
accumulation of fluid (vesicles) or fluid + inflammatory cells (pustules) within the epidermal layer
what do vesicles and pustules turn into
rupture to form erosions and crusting
erosions
loss of the epidermis with intact basal cell layer
crusts
degenerated cells + serum + WBCs, RBCs
what lesions would you want to sample the edge for biopsy
vesicles/pustules
erosions/ulcers
subepidermal vesicular/pustular dermatitis
accumulation of fluid or fluid + inflammatory cells below the epidermis (in BMZ)
what lesion occurs from sub epidermal dermatitis
ulceration due to splitting at the BMZ
what can lead to subepidermal dermatitis as a secondary lesion
- cytotoxic interface dermatitis
- neutrophilic inflammation
- hypoxia
- steroid drugs
folliculitis
inflammation of the hair follicle
perifolliculitis
perifollicular perivascular/nodular dermatitis
furunculosis
ruptured hair follicle leading to free keratin and hair shaft in the dermis
elicits an immune response to foreign body in dermis
perforating folliculitis
superficial rupture of hair follicles
luminal folliculitis
inflammatory cells that cross the follicular epithelium and accumulate in the lumen of the follicle
what causes luminal folliculitis
infectious (bacterial, fungi, demodex, pelodera)
mural folliculitis
inflammatory cells migrate into the follicular epithelium (NOT the lumen)
what causes mural folliculitis
infectious
auto-immune
immune-mediated
bulbitis
inflammation of the hair bulb and deep hair follicle
leads to alopecia with no other superficial lesions due to no hair follicle
what causes bulbitis
autoimmune
nodular to diffuse dermatitis
inflammation of the dermis in nodular aggregates or generalized/diffuse distribution
what causes nodular/diffuse dermatitis
neoplasia vs inflammatory (infectious vs noninfectious)
panniculitis
inflammation of the subcutis that occurs as an extension of dermatitis (dermal inflammation)
what causes panniculitis
infectious
metabolic
immune mediated
idiopathic
