Skin

Question 1

Hyperkeratosis

Answer 1

More keratin = more cells in S. corneum.

Psoriasis and Lichen planus.

Question 2

Parakeratosis

Answer 2

Retained nuclei in S granulosum, thinning, more turnover.

Psoriasis and dandruff.

Question 3

Acanthosis

Answer 3

Thickening of S spinosum

Question 4

Acantholysis

Answer 4

Lose desmosomes, so less cohesion between keratinocytes.

Pemphigus vulgaris.

Question 5

Spongiosis

Answer 5

Intercellular oedema in epidermis.

Vesicles in eczema (dermatitis).

Question 6

Histology of eczema/dermatitis

Answer 6

Acute: spongiosis, inflam infiltrate in dermis, dilated capillaries.
Chronic: acanthosis, crusting, scaling.

Question 7

Clinical features of Atopic dermatitis (eczema)

Answer 7

Infants: face & scalp.

Children+ : Flexural areas. Lichenification if chronic.

Question 8

Features of Contact dermatitis (eczema)

Answer 8

Erythma, swelling, pruritis.

Type IV hypersensitivity (nickel, rubber…), so affects ear lobes, neck, wrist, feet.

Question 9

Features of Seborrhoeic dermatitis

Answer 9

Inflammatory reaction to the yeast Malassezia.
Infants: cradle cap.
Adults: mild erythema, fine scaling, mild pruritus - eyebrows, eyelids, ears, chest.

Question 10

Layers of epidermis

Answer 10

S. corneum,
S. granulosum,
S. spinosum,
S. basale.

Question 11

Histology of Psoriasis

Answer 11

Parakeratosis, 
loss of S granulosum, 
clubbed rete ridges ("test tubes in a rack"), 
Munro's microabscesses. 
Proliferation.

Question 12

Associated features of Psoriasis

Answer 12

Nail changes: Pitting, Onycholysis, Subungual Hyperkeratosis;
Arthritis.

Question 13

Psoriasis - commonest form, with appearance

Answer 13

Chronic plaque psoriasis.

Salmon pink plaques, silver scale, outside of knees, elbows, scalp.

Question 14

Auspitz’ sign

Answer 14

Pin-point bleeding in psoriasis

Question 15

Koebner phenomenon

Answer 15

Linear lesions after trauma.
Seen in Psoriasis & Lichen planus (scratching),
and linear exposure to Molluscum & Warts.

Question 16

Lichen planus lesions

Answer 16

Pruritic, Purple, Polygonal, Papules, Plaques.

Mother of pearl sheen, Wickam’s striae.

Question 17

Histology of Lichen planus

Answer 17

Hyperkeratosis,
saw-toothing of rete ridges,
basal cell degeneration.

Question 18

Erythema multiforme appearance

Answer 18

Annular target lesions on hands and feet.

Pleomorphic (varied) lesions.

Question 19

Causes of Erythema multiforme

Answer 19

Infections: HSV, mycoplasma;
Drugs: penicillin, salicylates, anti-malarials.

Question 20

Nikolsky’s sign

Answer 20

Exfoliation with light rubbing.

Seen in TEN/SJS and pemphiguS.

Question 21

Sheets of skin detachment,

Answer 21

Stevens Johnson Syndrome

Question 22

Sheets of skin detachment, >30% body SA

Answer 22

Toxic Epidermal Necrolysis

Question 23

Causes of SJS/TEN

Answer 23

Drugs: sulfonamide Abx, anticonvulsants.

Question 24

Pityriasis rosea

Answer 24

Salmon pink rash (herald patch), then oval macules in Christmas tree distribution.
After viral illness.
Remits spontaneously.

Question 25

PemphiGoiD

Answer 25

Deep bullae (subepidermal). Robust.
IgG binds hemidesmosomes of basement membrane, linearly.
Elderly.
Eosinophils.

Question 26

PemphiGuS

Answer 26

Superficial bullae pop.
Skin and mucosal membranes.
IgG binds desmosomal proteins inside epidermis.
Net-like pattern. Acantholysis.

Question 27

DermAtitis herpetiformis

Answer 27

Itchy vesicles outside elbows. (Bullous.)
Subepidermal bullae (like pemphigoiD).
IgA binds basement mebrane: Neut & IgA at tips of dermal papillae.
Assoc: Coeliac.

Question 28

Seborrhoeic keratosis

Answer 28

Benign.
Rough waxy plaques, “stuck on”.
Elderly.

Question 29

Actinic keratosis

Answer 29

= Solar. 
Premalignant. 
Rough sandpaper. 
Sun. 
Spain: Solar elastosis, Parakeratosis, Atypical cells, Inflam, Not full thickness.

Question 30

Bowen’s disease

Answer 30

Pre-malignant - intra-epidermal SCC in situ.
Flat red scaly patches. Sun.
Full thickness, but BM intact.

Question 31

Keratoacanthoma

Answer 31

Rapid dome, ?necrotic centre.
Clears after 2-3 weeks of growth.
Looks like SCC.

Question 32

SCC

Answer 32

Bowen’s has involved dermis. May ulcerate.

Atypical cells spread through dermis.

Question 33

BCC

Answer 33

Rodent ulcer. Pearly. Telangectasia.
Slow. Rarely metastatic.
Mass of basal cells push into dermis.

Question 34

Melanocytic naevus

Answer 34

Benign melanoma

Question 35

Breslow thickness

Answer 35

Stage / prognosis of Malignant melanoma

Question 36

Malignant melanoma histology

Answer 36

Atypical melanocytes.
First grow horizontally - radial.
Then vertically, showing Buckshot (scatter) appearance.