Dermatology basics Flashcards
What’s included in examination of the skin?
Inspect:
- site and no. lesions
- pattern and configuration
Describe individual lesions: SCAM
- Size
- Colour
- Associated 2ndary change
- Morphology + Margin
Palpate:
- Surface
- Consistency
- Mobility
- Tenderness
- Temperature
Systematic check:
- Scalp + hair
- Nails
- Mucous membranes
What are some good ways to describe individual lesions?
SCAM
- Size
- Colour
- Associated 2ndary change
- Morphology + Margin
What is meant by ‘secondary changes’?
Secondary lesions
Problems that the rash/skin problem has caused. I.e. not part of original pathology
Define:
- Pruritus
- Lesion
- Rash
- Comedone
Pruritus: itching
Lesion: an area of altered skin
Rash: An eruption of areas of altered skin
Comedone: A plug in a sebaceous follicle containing altered sebum, bacteria and cellular debris. Two types: open (blackheads) and closed (whiteheads)
List and define some ways to describe lesion distribution?
Generalised: all over
Widespread: extensive cover
Localised: restricted to one area
Flexural: body folds (groin, neck, behind ears)
Extensor: Knees, elbows, shins
Pressure areas: sacrum, buttocks, heels
Dermatome: area supplied by single spinal nerve
Photosensitive: sun exposed areas (face, neck, back, hands
Koebner’s phenomenon: linear eruption arising at trauma site
What is Koebner’s phenomenon?
A linear eruption arising at the site of trauma
What is meant by
- Configuration
- Distribution
- Morphology
The pattern or shape of grouped lesions
The pattern of spread of lesions
Structure of the lesions themselves
List and define some ways to describe lesion configuration?
Discrete: individual lesions separated from each other
Confluent: lesions merging together
Linear: in a line
Target: concentric rings (circles within circles, like a dart board)
Annular: ring, circle
Discoid: round
Skin can change colour when there’s pathology. List and define terms used to describe.
Erythema: redness, caused by inflammation and vasodilatation
Petechiae, purpura, ecchymoses: red, purple colour, due to bleeding into skin or mucous membrane
Hypo-pigmentation: area of paler skin
De-pigmentation: areas of white skin due to absence of melanin
Hyper-pigmentation: darker areas of skin, can be post-inflammation
List and define terms used to describe morphology?
Macule: a flat area of altered skin
Patch: large flat area of altered skin
Papule: solid raised lesion < 5mm
Nodule: solid raised lesion >5mm
Plaque: palpable scaling raised lesion > 5mm
Vesicle: raised, clear, fluid filled lesion < 5mm
Bulla: raised, clear, fluid filled lesion > 5mm
Pustule: pus containing lesion < 5mm
Abscess: localised accumulation of pus in dermis or subcutaneous tissues
Wheal: transient raised lesion due to dermal oedema, i.e urticaria
Boil: staph infection around or within a hair follicle
Carbuncle: staph infection of adjacent hair follicles
List and define some examples of secondary lesions?
Lichenification: thickened, roughened, darkened skin due to excess itching
Excoriation: loss of epidermis due to itching
Scale: flakes of stratum corneum
Fissure: crack in skin die to excessive dryness
Crust: rough surface of dried serum, blood, bacteria, cellular debris that’s exuded through epidermis
Scar: new fibrous tissue which occurs post wound healing
Ulcer: loss of epidermis and dermis
Striae: linear areas that occur after pregnancy, growth spurt, steroid use
What types of scar are there?
Atrophic: thinning
Hypertrophic: hyperproliferation within wound boundary
Keloidal: hyperproliferation beyond wound boundary
What colours do striae progress through?
Purple to pink to white
Define:
- alopecia
- hirsutism
- hypertrichosis?
Alopecia: loss of hair
Hirsutism: androgen dependent hair growth in women
Hypertrichosis: non-androgen dependent pattern of hair growth, like in a naevus
List and define nail problems that are seen in dermatology.
Clubbing: loss of angle between posterior nail fold and nail plate
Koilonychia: spoon shaped depression of nail plate
Onycholysis: separation of the distal end of the nail bed
Pitting: punctuate depressions of nail plate
Causes of:
- clubbing
- koilonychia
- onycholysis
- pitting?
Clubbing: cyanotic heart disease, respiratory disease, IBD
Koilonychia: iron deficiency anaemia, congenital
Onycholysis: trauma, psoriasis, fungal nail
Pitting: psoriasis, eczema, alopecia
What are the functions of the skin?
Protective barrier against environment Temperature regulation Sensation Vitamin D synthesis Immune system Appearance
What three layers of skin are there?
List the skin appendages? Why are they called this?
Epidermis
Dermis
Sub-cutaneous layer
Hair Nails Sebaceous glands Sweat glands Because they’re formed by skin derived cells
Describe the layers of the epidermis? Give a brief description of each layer.
4 layers, going from deep to superficial - BSGC
- Stratum basale: actively dividing layer, deepest
- Stratum spinosum: differentiating cells
- Stratum granulosum: cells lose nuclei and contain granules of keratohyaline
(in thick skin i.e. soles there’s an extra layer: Stratum lucidum)
- Stratum corneum: layer of keratin, superficial layer
Which epidermis layer is this:
- Contains granules of keratohyaline
- Deepest layer
- Superficial layer
- Contains paler keratin
- Contains differentiating cells
- Contains cells with no nuclei
- Contains actively dividing cells
- Is also called the Horny layer
- Only seen in thick skin
- Granulosum
- Basale
- Corneum
- Lucidum
- Spinosum
- Granulosum
- Basale
- Corneum
- Lucidum
List and briefly describe the types of cells found in the epidermis?
Keratinocytes: produce keratin
Langerhans cells: present antigens and activate T lymphocytes
Melanocytes: produce melanin
Merkel cells: contain specialised nerve endings
What’s the function of:
- Keratin
- Melanin
Keratin: acts as a protective barrier
Melanin: gives pigment to skin and protects DNA from UV damage
What is the structure of the dermis? Explain the function of each component
Mainly collagen, also elastin and glycosaminoglycans
These provide strength and elasticity
Immune cells Nerves Skin appendages (sebaceous glands, hair follicles) Lymph vessels Blood vessels
What produces collagen, elastin and glycosaminoglycans in the dermis?
Fibroblasts
What are the different types of hair?
Lanugo hair: fine, long hair in the foetus
Vellus hair: fine, short hair on all body surfaces
Terminal hair: coarse, long hair on scalp, eyebrows, eyelashes, pubic areas
Describe the structure of a hair?
Hair shaft: keratinised tube
Hair bulb: actively dividing cells and melanocytes giving pigment to hair
What’s the growth cycle of a hair follicle?
ACT
Anagen: long growing phase
Catagen: short regressing phase
Telogen: resting/shedding phase
What’s the structure of a nail? List some pathologies that occur in each bit?
Nail plate: hard keratin
Discoloured, thickened nails
Nail matrix: at posterior nail fold, where the keratin arises
Pits and ridges
Nail bed: capillaries
Splinter haemorrhages
What is a sebaceous gland?
Produces sebum via a hair follicle
Secrete sebum onto the skin to lubricate and waterproof the skin
What is a pilosebaceous unit?
Sebaceous gland + hair follicle
What stimulates sebaceous glands?
What does sebum do?
Conversion of androgens to dihydrotestosterone
So they become active at puberty
Sebum lubricates and waterproofs the skin
What are the types of sweat gland?
Eccrine: all over skin
Apocrine: in axillae, areolae, genitalia, anus
Only function from puberty onwards
What controls sweat glands?
Sympathetic nervous system
List and give examples of pathologies that can occur in the epidermis?
Epidermal turnover time: psoriasis is when there’s a reduced epidermal turnover time
Change in structure or loss of epidermis: scales, ulcers, crusting
Change in pigmentation: hypo or hyper-pigmented
List and give examples of pathologies that can occur in the dermis?
Loss of dermis or change in contour: papules, nodules, skin atrophy
Disorders of skin appendages: hair problems, sebaceous glands (acne)
Lymphatic and blood vessel: erythema (vasodilation), urticaria (increased permeability of small vessels), purpura (capillary leakage)
List and give examples of pathologies that can occur in the hair?
Reduced or absent melanin pigment production: grey or white hair
Changes in duration of growth cycle: hair loss (premature entry of hair follicles into the telogen phase)
Shaft abnormalities
What’s the pathogenesis of hair loss?
Premature entry of hair follicle into the telogen phase, which is shedding
List and give examples of pathologies that can occur in the sebaceous glands?
Increased sebum production + bacterial colonisation: acne
Sebaceous gland hyperplasia
What is:
- Sebaceous gland hyperplasia
- Hidradenitis suppurativa
- Hyperhidrosis?
**
List and give examples of pathologies that can occur in the sweat glands?
Inflammation/infection of the apocrine glands: hidradenitis suppurativa
Overactivity of eccrine glands: hyperhidrosis
What are the stages of wound healing?
- Haemostasis:
- Vasoconstriction
- Platelet aggregation
- Clot formation - Inflammation:
- Vasodilatation
- Migration of macrophages + neutrophils
- Phagocytosis of cell debris and bacteria - Proliferation
- Granulation tissue formed by fibroblasts
- Angiogensis
- Re-epithelialisation - Remodelling
- Collagen fibre re-organisation
- Scar maturation
What is re-epithelialisation?
Which stage of wound healing is it?
Epidermal cell proliferation and migration
In stage 3: proliferation
