Pathology of Skin Flashcards
What is the peidermis mainly made up of
Maturing squamous cells
Where are melanocytes found
At the dermo-epidermal junction and in the basal layer
What is the ratio of melanocytes to basal cells
1:10
What is the granular layer rich in
Keratohyalin granules
What is the corneal layer made up of
Differentiated keratinised cells
What happens to corneocytes
They are shed from the surface and cause house dust
How is pigment shown
Melanocytes transfer pigment to keratinocytes via dendritic processes
Where are the Langerhan cells located
In the upper and mid-epidermis
Why are Langerhans cells important
In initiating inflammation
What is the difference in melanocytes in a pale skinned person compared to a darker skinned person
They have the same number of melanocytes but darker skinned people make more melanin
The matrix of the dermis is made up of what
Type 1 and type 3 collagen
What colour is a) collagen when and b) elastin when stained
Collagen is pink and elastin is blue
What is the ground substance of the dermis made up of
Hyaluronic acid and chondriotin sulphate
Describe the appearance and location of the papillary dermis
Thin and lies just beneath the epidermis
Describe the appearance and location of the reticular dermis
Thicker than the papillary dermis and contains type 1 collagen
What does the reticular dermis contain
Appendage structures - sweat glands, pilosebaceous units
What is the epidermal Basment Membrane made of
laminin and collagen IV
What type of cells appear to have halos around them
Melanocytes
What is parakeratosis
Persistence of nuclei in the keratin layer - the skin turnover is too high
Define papillomatosis
irregular epithelial thickening
Give an example of papillomatosis
Acanthiosis nigricans
What are the 4 main reaction patterns of inflammatory skin diseases
Spongiotic-intraepidermal oedema (eczema)
Psoriasiform-elongation of the rete ridges (psoriasis)
Lichenoid-basal layer damage (pemphigoid, pemphigus and dermatitis herpetiformis)
What are Munro micro abscess
A collection of neutrophils and classsically psoriasis
Where are 3 common sites of acne
Face
Upper back
Anterior chest
What are open comedones
Blackhead since it is oxidised
What causes a yellow head
A build up of Sebum and keratine cloggasge
Describe the aetiology of acne
Increased androgens at puberty, increased angrogen sensitivity of sebaceious glands
keratin plugging of pilosebaceious units
infection with anaerobic bacterium corynebacterium acnes
Rosacea is more common in females than males. true or false
True
What are some common features of rosacea
Recurrent facial flushing
Visible blood vessels
Pustules
Thickening of skin - rhinophyma
What are some triggers of rosacea
Sunlight
Alcohol
Spicy foods
Stress
What are sometimes found in the hair follicles under the microscope in patients with rosacea
Demodex mite in the sebaceious glands
What 2 things occur as a secondary phenomenon in many skin disease
eczema
herpes virus infection
burns
what type of disease have blisters as the primary feature
Immunobullous diseases
What are 3 examples of immunobullous diseases
Pemphigus
Bullous pemphigoid
Dermatitis Herpetiformis
What histologically happens in pemphigus
Loss of integrity of epidermal cell adhesion
What is the general treatment for pemphigus
Steroids
Who is usually affected by pemphigus
Middle aged men or women
In simple terms, describe pemphigus
Rare autoimmune bullous disease which is a problem involving cell to cell adhesion
What is the end result in pemphigus vulgaris
Acantholysis
What forms on the cell surface of pemphigus vulgaris
Immune complexes
What is the role of desmoglein 3 in pemphigus vulgaris
It maintains desmosomal attachments
What does Pemphigus Vulgaris produce
Fluid filled blisters which rupture to form shallow erosions
What areas of the body are affected by Pemphigus Vulgaris
Scalp Face Axillae groin Trunk
What process is common to all variants of pemphigus ?
Acantholysis (lysis of intercellular adhesion sites)
What is bullous pemphigoid
Subepidermal blister
What do the IgG antibodies do in Bullous pemphigoid
They react with a major and/or minor antigen of the hemidesmosomes anchoring basal cells to the basement membrane.