Pathology of the Skin Flashcards
Parakeratosis
Persistence of nuclei in the keratin layer, due to excessive differentiation of keratinocytes and high speed of turnover
Hyperkeratosis
Increased thickness of keratin layer
Acanthosis
Increased thickness of epithelium
Papillomatosis
Irregular epithelial thickening
Spongiosis
Oedema fluid between squamous appears to increase prominence of intercellular prickles
What are the 4 main classifications of inflammatory skin disease?
- Spongiotic (intraepidermal oedema)
- Psorisiform (elongation of rete ridges)
- Lichenoid (basal layer damage)
- Vesiculobullous (blistering)
Koebner Phenomenon
Refers to skin lesions appearing on lines of trauma
What are the histological characteristics of Psoriasis?
Elongation, clubbing and fusion of the rate ridges, parakeratosis and superficial blood vessels
What is the most common lichenoid disorder?
Lichen planus - Itchy flat topped violaceous papules
What are histological features of lichen planus?
Irregular sawtooth acanthosis, pigment incontinence (pigments have dropped into the dermis due to damage to basal layer)
Which antibodies are involved in pemphigus vulgaris and bullous pemphigoid?
IgG
Which antibodies are involved in dermatitis herpetiformis?
IgA
Pemphigus
Rare autoimmune bulls disease, of which there are 4 types - the most common being pemphigus vulgaris
What is common to all variants of pemphigus?
Acantholysis - lysis of intercellular adhesion sites (cells all separate)
In pemphigus vulgaris, what do the autoantibodies act against?
Desmoglein 3 (maintains desmosomal attachments)
In bullous pemphigoid, what do the autoantibodies act against?
Antigen of the hemidesmosomes anchoring basal cells to basement membrane.
What is a hallmark of immunofluorescence in BP?
Linear arrangement of IgG fluorescence along basement membrane
What is the hallmark of dermatitis herpetiformitis?
Papillary dermal micro abscesses, particularly on the buttocks - look like ‘scratch lesions’