Derm Physiology

Question 1

How do you describe a non pigmented lesion?

Answer 1

SCAM
Size/Shape
Colour
Associated secondary change
Morphology/Margin (border)

Question 2

How do you describe a pigmented lesion?

Answer 2

ABCD
Asymmetry
irregular Borders
2 or more Colours within lesion
Diameter >6mm

Question 3

What does ABCD description indicate

Answer 3

presence of any feature increases likelihood of melanoma

Question 4

Naevus

Answer 4

localised malformation of tissue structures

Question 5

prutitus

Answer 5

itching

Question 6

lesion

Answer 6

area of altered skin

Question 7

comedone

Answer 7

plug in sebaceous follicle containing altered sebum, bacteria and cellular debris; can be either open (blackhead) or closed (white head)

Question 8

Flexural

Answer 8

body folds i.e. groin, neck, behind ears, popliteal and antecubital fossa

Question 9

extensor

Answer 9

knees
elbows
shins

Question 10

pressure areas

Answer 10

sacrum
buttocks
ankles
heels

Question 11

dermatome

Answer 11

area of skin supplied by single spinal nerve

Question 12

Koebner phenomenon

Answer 12

Linear eruption (rash) arising at site of trauma

Question 13

discrete and confluent

Answer 13

discrete - individual lesions separated from each other

confluent - lesions merging together

Question 14

Target
Annular
Discoid/nummular

Answer 14

T- concentric rings
A- like a circle or ring
D- coin shaped/round lesion

Question 15

Erythema

Answer 15

redness (due to inflam and vasodilation) which blanches on pressure

Question 16

Purpura

Answer 16

red or purple colour (due to bleeding into skin or MM) which doesn’t blanch on pressure

Question 17

petechiae

Answer 17

small purpura

Question 18

ecchymoses

Answer 18

large bruise like purpura

Question 19

macule

Answer 19

flat area of altered colour

Question 20

patch

Answer 20

large area of altered colour or texture

Question 21

papule

Answer 21

solid raised lesion <0.5cm diameter

Question 22

nodule

Answer 22

solid raised lesion >0.5cm in diameter with a deeper component

Question 23

plaque

Answer 23

palpable scaling raised lesion >0.5cm in diameter

Question 24

vesicle (small blister)

Answer 24

raised clear fluid filled lesion <0.5cm diameter

Question 25

bulla (large blister)

Answer 25

raised clear fluid filled lesion >0.5cm diameter

Question 26

pustule

Answer 26

pus containing lesion <0.5cm diameter

Question 27

abscess

Answer 27

localised accumulation of pus in the dermis or subcut tissues

Question 28

w(h)eal

Answer 28

transient raised lesion due to dermal oedema

Question 29

Boil/furuncle

Answer 29

staph infection around or in hair follicle

Question 30

carbuncle

Answer 30

staph infection of adjacent hair follicles (multiple boils/furuncles)

Question 31

excoriation

Answer 31

loss of epidermis following trauma

Question 32

lichenification

Answer 32

well defined roughening of skin with accentuation of skin markings

Question 33

scales

Answer 33

flakes of stratum corneum

Question 34

crust

Answer 34

rough surface consisting of dried serum, blood, bacteria and cellular debris that has exuded through an eroded epidermis

Question 35

Scar

Answer 35

new fibrous tissue which occurs post-wound healing and maybe be atrophic, hypertrophic, or keloidal (hyperproliferation beyond wound boundary)

Question 36

Ulcer

Answer 36

loss of epidermis and dermis

Question 37

fissure

Answer 37

epidermal crack often due to excess dryness

Question 38

striae

Answer 38

linear areas which progress from purple to pink to white with histopathological appearance of a scar

Question 39

hypertrichosis

Answer 39

non-androgen dependent pattern of excessive hair growth

Question 40

clubbing

Answer 40

loss of angel between posterior nail fold and nail plate

associated with lung disease, cyanotic heart disease, IBS

Question 41

koilonychia

Answer 41

spooned nails
(iron deficiency anaemia, congenital)

Question 42

onycholysis

Answer 42

separation of distal end of nail plate from nail bed (trauma, psoriasis, fungal nail infection and hyperthyroidism)

Question 43

Pitting

Answer 43

punctate depressions of the nail plate (psoriasis, eczema, alopecia)

Question 44

skin functions

Answer 44

• protective barrier
• temp regulation
• sensation
• vit D synthesis
• immunosurveillance
• appearance /cosmesis

Question 45

4 cell types in epidermis and functions

Answer 45

• keratinocytes: produce keratin as protective barrier
• Langerhans: present antigens and active T lympho
• Melanocytes: produce melanin for pigmentation and protection from UV
• Merkel: contain specialised nerve endings for sensation

Question 46

4 layers of epidermis

Answer 46

1) stratum corneum: keratin, most superficial
2) straum granulosum: cells lose nuclei and contain granules of keratohyaline. They secrete lipid into intercellular spaces
3) stratum spinosum: differentiating cells
4) stratum basale: actively dividing cells, deepest
5) stratum lacidum: present in areas of thick skin (sole) paler, compact keratin

Question 47

epidermal pathophysiology

Answer 47

1) changes in epidermal turnover time (psoriasis)
2) changes in surface of skin or loss of epidermis (scales, crusting, exudate)
3) changes in pigmentation of skin (hypo/hyper pigmentation)

Question 48

what is dermis made up of?

Answer 48

collagen, elastin and glycosaminoglycans

immune cells, nerves, skin appendages, lymphatic and blood vessels

Question 49

dermis pathophysiology

Answer 49

1) changes in contour of skin or loss of dermis (papules, nodules, atrophy)
2) disorders of skin appendages (hair, acne)
3) changes related to lymphatic and blood vessels (erythema. urticaria)

Question 50

3 Types of hair

Answer 50

1) lanugo - fine long hair in fetus
2) vellus - fine short hair
3) terminal - coarse long hair