Pathophysiology

Question 1

Psoriasis pathophysiology?

Answer 1

genetic component

1) Keratinocytes under stress (intiated by trauma/drugs/unknown allergen) lead to activation of dermal dendrites
2) Dermal dendrites activate T helper cells
4) T helper cells release growth factors (TNFa), adhesion molecules and other cytokines which propel inflammation and epidermal turnover

Question 2

Psoriasis presentation?

Answer 2

Epidermal cell turnover increased (silvery scales)
Granular layer absent
Affects extensor surfaces
itchy - bleed
thinning epidermal over blood vessels, multiple bleeding pts
Well demarcated papulo-squamous red scaly plaques

Question 3

Eczema?

Answer 3

Impairment of skin barrier function due to mutations in fillagrin gene (fillagrin holds keratin filaments together.)
This leads to stressed keratinocytes, which attract dermal dendritic cells (Ag presenting, chemokine releasers), and therefore T cells. Immune response intiated.
Defective barrier allows access/sensitization to allergens and promotes bacterial colonisation

Question 4

Eczema presentation?

Answer 4

Red inflamed patches
Flexor surfaces
common children

Question 5

Hyperkeratosis

Answer 5

Increased thickness of keratin layer

Question 6

Parakeratosis

Answer 6

Persistence of nuclei in the keratin layer

Question 7

Acanthosis

Answer 7

Increased thickness of prickle cell layer

Question 8

Basic biochemistry of porphyrias?

Answer 8

Porphyrias deposit in skin, energy from sun absorbed.

Porphyria moves deeper into the skin and can intiate a secondary reaction and inflammatory immune response.

Question 9

Photoallergy is also known as - , it is a form of - - -

Answer 9

photodermatitis,

allergic contact dermatitis

Question 10

Phototoxcitiy does not involve the - -. It is a - induced skin reaction.

Answer 10

immune system, chemically

Question 11

Erythropoetic protophoryia usually presents in - and most cases are -. Clinical presentation involves - - - and - within few mins exposure to sun.

Answer 11

childhood
congenital (inborn metabolic defects)
pruritus, erythema, swelling and pain

Question 12

Porphyria cutanea tarda typical clinical presentation involves - and - as well as -pigmentation, -trichosis and solar -

Answer 12

Blister, fragility
Hyperpigmentation
Hypertrichosis
Solar urticaria 
morphoea which is localised (patches on skin)
scleroderma (hard bits of skin)

Question 13

Acute intermittent porphyria presents with acute -, as well as peripheral neuropathy syndromes such as – syndrome, and - multiplex.

Answer 13

abdomen
gullian barre
mononeuritis
psychosis

Question 14

Lesion is

Answer 14

Lesion is traumatic or pathogic loss of normal tissue continuity, structure or function

Question 15

Rash is

Answer 15

temporary eruption of skin

Question 16

Flat lesions called?

Answer 16

Macule is flat spot <1cm

Patch >1cm

Question 17

Raised lesions called

Answer 17

Nodule if >0.5cm

Papule if <0.5cm

Question 18

Plaque is

Answer 18

ELEVATED edges and flatter surface >1cm

Question 19

Wheal is

Answer 19

localised skin edema, compressible

Question 20

Lichenification

Answer 20

thickened leathery roughening of skin caused by scratching

Question 21

Blisters are

Answer 21

Circumscribed elevations f skin caused by fluid under or within epidermis

Question 22

Pustules are

Answer 22

sircumscribed elevations of skin -pus filled

Question 23

Vesicles are

Answer 23

<1cm blister

Question 24

Bullae are

Answer 24

> 1cm blister

Question 25

Erosion is

Answer 25

loss of superficial epidermis, surface moist but does not bleed

Question 26

Ulcer is

Answer 26

Skin defect where there is loss of epidermis and papillary layer of dermis - may extend to subcutaneous tissue

Question 27

Callus is?

Answer 27

Hyperkeratotic plaque of skin develops because of pressure or friction

Question 28

Purpura is

Answer 28

reddening of skin due to extraversion of blood - doesn't blanche

Question 29

Petechia

Answer 29

small (1-2mm) area of purpura

Question 30

Cyst is?

Answer 30

Nodule containg semi-solid material

Question 31

Onycholyisis is?

Answer 31

seperation of nail plate from nail bed

Question 32

Alopecia?

Answer 32

loss of hair

Question 33

Hypertrichosis

Answer 33

general excess growth (hair, nails etc)

Question 34

Hirsutes?

Answer 34

excess growth in male pattern (i.e. beard in women)

Question 35

Enzyme deficient in acute intermittent porphyria?

Answer 35

PBG Deaminase (high up metabolic pathway)

Question 36

Enzyme deficient in porphyria cutanea tarda?

Answer 36

Uroporphyrinogen Decarboxylase (middle metabolic pathway)

Question 37

Enzyme deficient in erythropoietic protoporphyria?

Answer 37

Ferrochelatase (bottom of metabolic pathway)

Question 38

Discoid eczema is?

Answer 38

well defined, erythematus and scaly "discs" of eczema | Often atopic

Question 39

Diagnostic criteria for eczema?

Answer 39

``` Itch plus 3+ of: Visible flexural rash* History of flexural rash* Personal history of atopy (or first degree relative if under 4 yo) Generally dry skin Onset before age 2 years ```

Question 40

Immunopathology of contact allergic dermatitis?

Answer 40

Langerhans cell in epidermis processes antigen antigen is then presented to Th cells Sensitised T cells proliferate epidermis and cause damage = spongiosis

Question 41

Contact allergic dermatitis is inflammation in contact with an?

Answer 41

allergen

Question 42

Irritant contact dermatitis is inflammation in response to?

Answer 42

non-specific physical irritation rather than a specific allergic reaction e.g. soap, detergent, nappy difficult to distinguish from allergic ?

Question 43

Atopic eczema is caused by?

Answer 43

Genetic & environmental factors resulting in inflammation itching,not sleeping, affects whole family w kids

Question 44

Chronic changes of atopic eczema?

Answer 44

Lichenification Excoriation – erosion brought about by scratching Secondary infection – high carriage Staph A, erosions good carrier bacteria

Question 45

Eczema herpeticum is caused by? Presents as?

Answer 45

Herpes simplex virus monomorphic punched out lesions fecer

Question 46

Stasis eczema is secondary to?

Answer 46

hydrostatic pressure oedema red cell extravasation

Question 47

What is "cradle cap"?

Answer 47

Seborrhoeic dermatitis

Question 48

Pompholyx eczema is characterised by?

Answer 48

Spongiotic vesicles

Question 49

Photosensitive eczema is in response to sun exposure t/f

Answer 49

t

Question 50

What is a chronic leg ulcer?

Answer 50

open lesion between the knee and ankle joint that remains unhealed for at least 4 weeks.

Question 51

60-80% of leg ulcers are arterial in nature

Answer 51

F | 60-80% of leg ulcers are VENOUS in nature

Question 52

Features of arterial ulcers? FEED P

Answer 52

Full thickness defect Embolic "showering" on the toes Extremities Diabetics Punched out appearance

Question 53

Features of venous ulcers? VVERD

Answer 53

``` Varicose veins Varying depths Exudative and painful Recurrent Distal leg and ankle ```