Derm Physiology Flashcards
How do you describe a non pigmented lesion?
SCAM Size/Shape Colour Associated secondary change Morphology/Margin (border)
How do you describe a pigmented lesion?
ABCD Asymmetry irregular Borders 2 or more Colours within lesion Diameter >6mm
What does ABCD description indicate
presence of any feature increases likelihood of melanoma
Naevus
localised malformation of tissue structures
prutitus
itching
lesion
area of altered skin
comedone
plug in sebaceous follicle containing altered sebum, bacteria and cellular debris; can be either open (blackhead) or closed (white head)
Flexural
body folds i.e. groin, neck, behind ears, popliteal and antecubital fossa
extensor
knees
elbows
shins
pressure areas
sacrum
buttocks
ankles
heels
dermatome
area of skin supplied by single spinal nerve
Koebner phenomenon
Linear eruption (rash) arising at site of trauma
discrete and confluent
discrete - individual lesions separated from each other
confluent - lesions merging together
Target
Annular
Discoid/nummular
T- concentric rings
A- like a circle or ring
D- coin shaped/round lesion
Erythema
redness (due to inflam and vasodilation) which blanches on pressure
Purpura
red or purple colour (due to bleeding into skin or MM) which doesn’t blanch on pressure
petechiae
small purpura
ecchymoses
large bruise like purpura
macule
flat area of altered colour
patch
large area of altered colour or texture
papule
solid raised lesion <0.5cm diameter
nodule
solid raised lesion >0.5cm in diameter with a deeper component
plaque
palpable scaling raised lesion >0.5cm in diameter
vesicle (small blister)
raised clear fluid filled lesion <0.5cm diameter
bulla (large blister)
raised clear fluid filled lesion >0.5cm diameter
pustule
pus containing lesion <0.5cm diameter
abscess
localised accumulation of pus in the dermis or subcut tissues
w(h)eal
transient raised lesion due to dermal oedema
Boil/furuncle
staph infection around or in hair follicle
carbuncle
staph infection of adjacent hair follicles (multiple boils/furuncles)
excoriation
loss of epidermis following trauma
lichenification
well defined roughening of skin with accentuation of skin markings
scales
flakes of stratum corneum
crust
rough surface consisting of dried serum, blood, bacteria and cellular debris that has exuded through an eroded epidermis
Scar
new fibrous tissue which occurs post-wound healing and maybe be atrophic, hypertrophic, or keloidal (hyperproliferation beyond wound boundary)
Ulcer
loss of epidermis and dermis
fissure
epidermal crack often due to excess dryness
striae
linear areas which progress from purple to pink to white with histopathological appearance of a scar
hypertrichosis
non-androgen dependent pattern of excessive hair growth
clubbing
loss of angel between posterior nail fold and nail plate
associated with lung disease, cyanotic heart disease, IBS
koilonychia
spooned nails (iron deficiency anaemia, congenital)
onycholysis
separation of distal end of nail plate from nail bed (trauma, psoriasis, fungal nail infection and hyperthyroidism)
Pitting
punctate depressions of the nail plate (psoriasis, eczema, alopecia)
skin functions
- protective barrier
- temp regulation
- sensation
- vit D synthesis
- immunosurveillance
- appearance /cosmesis
4 cell types in epidermis and functions
- 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
4 layers of epidermis
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
epidermal pathophysiology
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)
what is dermis made up of?
collagen, elastin and glycosaminoglycans
immune cells, nerves, skin appendages, lymphatic and blood vessels
dermis pathophysiology
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)
3 Types of hair
1) lanugo - fine long hair in fetus
2) vellus - fine short hair
3) terminal - coarse long hair
