Pathology of Rashes Flashcards
What is hyerkeratosis?
increased thickness of keratin layer
What is parakeratosis?
persistence of nuclei in the keratin layer
What is acanthosis?
increased thickness of epithlieum
What is papillomatosis?
Irregular eptihelial thickening
What is spongiosis?
oedema fluid between squames increases prominence of intercellular prickles
-in severe case vesicles filled by oedema fluid develop
4 main reaction patterns?
- spongiotic-intraepidermal oedema
- psoriasiform-elongation
- lichenoid-basal layer damage
- vesiculobullous-blistering
What type of reaction pattern is eczema?
spongiotic-intraepidermal oedema
What type of reaction pattern is psoriasis?
psoriasiform-elongation of the rete ridges
What type of reaction is lichen planus and lupus?
lichenoid-basal layer damage
What type of reaction is pemphigoid, pemphigus and dermatitis herpetiformis?
vesiculobullous-blistering
what is the basic pathogenesis of psoriasis?
epidermal hyperplasia leading to increased epidermal turnover
What gene type is psoriasis linked to sometimes?
associated specific HLA types
What do lichenoid disorders look like?
itchy flat topped violaceous papules (violet)
Lichen planus histology?
- irregular sawtooth acanthosis
- hypergranulosis + orthohyperkeratosis
- bad-like upper dermal infiltrate of lymphocytes
- basal damage with formation of cytoid bodies
range of lichenoid disorders?
- lichen planus
- vacuolar interface change
pemphigus
autoimmune bullous disease
basic pathology of pemphigus
loss of integrity of epidermal cell adhesion i.e. epidermal cells float apart
most common pemphigus?
pemphigus vulgaris
Pemphigus vulgaris pathology?
-IgG auto-antibodies made against desmoglein 3 desmoglein 3 maintains demosomal attachments, immune complexes form on cell surface, complement activation & protease realease -> acantholysis
What is acantholysis?
lysis of intercellular adhesion sites
What body parts does pemphigus vulgaris usually involve?
- scalp
- face
- axillae
- groin
- trunk
- may effect mucosa e.g. mouth + resp.tract
bullous pemphigoid where is blister?
subepidermal blister
-no evidence of acantholysis
What do IgG antibodies react with in bullous pemphigoid?
antigen of hemidesmosomes anchoring basal cells to basement membrane
Dermatitis herpetiformis what is it and what does it tend to be associated with?
autoimmune bullous disease associated with coeliac disease
What antibody associated with dermatitis herpetiformis?
IgA
Acne common places
face, upper back, anterior chest
What are 4 triggers of rosacea?
- sunlight
- alcohol
- spicy foods
- stress
What is link with rosacea and demodex mites?
sometimes mites get like stuck in the hair follicles and get caught up in the inflammatory process
