Week 3: Dermatology Flashcards
Taking a dermatological history
- presenting complaint- nature, site and duration of problem
- history of presenting complaint
- Initial appearance and evolution of lesion*
- Symptoms (particularly itch and pain)*
- Aggravating and relieving factors
- Previous and current treatments (effective or not)
- Recent contact, stressful events, illness and travel
- History of sunburn and use of tanning machines*
- Skin type (see page 70)*
- PMH
- history of atopy, skin cancer, suspicious skin lesions
- family history
- family history of skin disease
- social history
- occupation
- improvement of lesion when away from work
- medication and allergies
- regular
- recent
- over the counter
- impact on quality of life
examining the skin
There are four important principles in performing a good examination of the skin: INSPECT, DESCRIBE, PALPATE and SYSTEMATIC CHECK
inspect
- General observation
- Site and number of lesion(s)
- If multiple, pattern of distribution and configuration
describe : lesion
SCAM
- Size (the widest diameter),Shape
- Colour
- Associated secondary change
- Morphology, Margin (border)
describe : pigmented lesion
ABCD
(the presence of any of these features increase the likelihood of melanoma):
- Asymmetry (lack of mirror image in any of the four quadrants)
- Irregular Border
- Two or more Colours within the lesion
- Diameter > 6mm
palpate
Surface
Consistency
Mobility
Tenderness
Temperature
examples
- Indurated (SCC)
- Hard (dermatofibroma)
- Soft (skin tag)
- Sclerotic (venous stasis ulcers)
systematic check
Examine the nails, scalp, hair & mucous membranes General examination of all systems
pruritus
itching
lesion
area of altered skin
rash
an eruption
naevus
a localised malformation of tissue structure
e.g. pigmented melanocytic naevus (mole)
comdedone
A plug in a sebaceous follicle containing altered sebum, bacteria and cellular debris; can present as either open (blackheads) or closed (whiteheads)
generalised
all over the body
widespread
extensive
localised
restricted to one area of skin only
flexural
Body folds i.e. groin, neck, behind ears, popliteal and antecubital fossa
extensor
knees, elbow, shins
pressure areas
Sacrum, buttocks, ankles, heels
dermatome
An area of skin supplied by a single spinal nerve
photosensitive
Affects sun-exposed areas such as face, neck and back of hands
koebner
A linear eruption arising at site of trauma
e.g. psoriasis
discrete
individual lesions separated from each other
confluent
lesions merging together
linear
in a line
targert
concentric rings -like a dart board
e.g. erythema
annular
like a circle or ring
e.g. tinea corporis - ringworm
discoid/nummular
coin shaped/round lesion
e.g. discoid eczema
erythema
Redness (due to inflammation and vasodilatation) which blanches on pressure
e.g. palmar erythema
purpura
Meaning
Redness (due to inflammation and vasodilatation) which does not blanches on pressure
Example:
Red or purple colour (due to bleeding into the skin or mucous membrane) which does not blanch on pressure – petechiae (small pinpoint macules) and ecchymoses (larger bruise-like patches)
e.g. henoch-schonlein purpura (palpable small vessel vasculitis)
hypo-pigementation
area of paler skin
e.g. pityriasis versicolor (superficial fungus infection)
de-pigmentation
white skin due to absence of melanin
e.g. vitiligo (loss of skin melanocytes)
hyperpigmentation
darker skin which may be due to various causes e.g. post-inflammatory
e.g. melasma
macule
A flat area of altered colour <1cm
e.g. freckle
patch
Larger flat area of altered colour or texture
>1cm
papule
Solid raised lesion < 0.5cm in diameter
nodule
Solid raised lesion >0.5cm in diameter with a deeper component
plaque
Palpable scaling raised lesion >0.5cm in diameter
e.g. psoriasis
vesicle
Raised, clear fluid-filled lesion <0.5cm in diameter
bulla
Raised, clear fluid-filled lesion >0.5cm in diameter
pustule
Pus-containing lesion <0.5cm in diameter
abscess
Localised accumulation of pus in the dermis or subcutaneous tissues
whealTransient raised lesion due to dermal oedema
Transient raised lesion due to dermal oedema
boil/furuncle
Staphylococcal infection around or within a hair follicle
carbuncle
Staphylococcal 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
scale
flakes of stratum corneum
e.g. psoriasis showing silvery scales
\
crust
Rough surface consisting of dried serum, blood, bacteria and cellular debris that has exuded through an eroded epidermis (e.g. from a burst blister)
e.g. impetigo
scar
New fibrous tissue which occurs post-wound healing, and may be atrophic (thinning), hypertrophic (hyperproliferation within wound boundary), or keloidal (hyperproliferation beyond wound boundary)
e.g. keloid
ulcer
Loss of epidermis and dermis (heals with scarring)
fissure
An epidermal crack often due to excess dryness
e.g. eczema
striae
Linear areas which progress from purple to pink to white, with the histopathological appearance of a scar (associated with excessive steroid usage and glucocorticoid production, growth spurts and pregnancy)
alopecia
loss of hair
e.g. alopecia areata
hirsutism
Meaning
Loss of hair Example:
Androgen-dependent hair growth in a female
hypertrichosis
Non-androgen dependent pattern of excessive hair growth
clubbing
Loss of angle between the posterior nail fold and nail plate (associations include suppurative lung disease, cyanotic heart disease, inflammatory bowel disease and idiopathic)
koilonychia
Spoon-shaped depression of the nail plate
(associations include iron-deficiency anaemia, congenital and idiopathic)
onycholysis
Separation of the distal end of the nail plate from nail bed (associations include trauma, psoriasis, fungal nail infection and hyperthyroidism)
pitting
Punctate depressions of the nail plate
(associations include psoriasis, eczema and alopecia areata)
function of normal skin
i) Protective barrier against environmental insults
ii) Temperature regulation
iii) Sensation
iv) Vitamin D synthesis
v) Immunosurveillance
vi) Appearance/cosmesis
structure of normal skin
It is composed of the epidermis and dermis overlying subcutaneous tissue. The skin appendages (structures formed by skin-derived cells) are hair, nails, sebaceous glands and sweat glands.
epidermus has how many layers
4
/ 5
In areas of thick skin such as the sole, there is a fifth layer, stratum lucidum, beneath the stratum corneum. This consists of paler, compact keratin.
name 4 layers of epidermis
cells in the epidermis
Pathology of the epidermis may involve:
a) changes in epidermal turnover time - e.g. psoriasis (reduced epidermal turnover time)
b) changes in the surface of the skin or loss of epidermis - e.g. scales, crusting, exudate, ulcer
c) changes in pigmentation of the skin - e.g. hypo- or hyper-pigmented skin
dermis
The dermis is made up of collagen (mainly), elastin and glycosaminoglycans, which are synthesised by fibroblasts. Collectively, they provide the dermis with strength and elasticity.
The dermis also contains immune cells, nerves, skin appendages as well as lymphatic and blood vessels.
pathology of the dermis
a) changes in the contour of the skin or loss of dermis e.g. formation of
papules, nodules, skin atrophy and ulcers
b) disorders of skin appendages e.g. disorders of hair, acne (disorder of
sebaceous glands)
c) changes related to lymphatic and blood vessels e.g. erythema
(vasodilatation), urticaria (increased permeability of capillaries and small venules), purpura (capillary leakage)
types of hair
There are 3 main types of hair:
a) lanugo hair (fine long hair in fetus)
b) vellus hair (fine short hair on all body surfaces)
c) terminal hair (coarse long hair on the scalp, eyebrows, eyelashes andpubic areas)
structure of hair
Each hair consists of modified keratin and is divided into the hair shaft (a keratinized
tube) and hair bulb (actively dividing cells, and melanocytes which give pigment to
the hair).
hair follicles
Each hair follicle enters its own growth cycle. This occurs in 3 main phases:
a) anagen (long growing phase)
b) catagen (short regressing phase)
c) telogen (resting/shedding phase)
pathology of the hair
a) reduced or absent melanin pigment production e.g. grey or white hair
b) changes in duration of the growth cycle e.g. hair loss (premature entry of
hair follicles into the telogen phase) c) shaft abnormalities
nails
The nail is made up of a nail plate (hard keratin) which arises from the nail matrix at the posterior nail fold, and rests on the nail bed.
The nail bed contains blood capillaries which gives the pink colour of the nails.
pathology of the nails
a) abnormalities of the nail matrix e.g. pits and ridges
b) abnormalities of the nail bed e.g. splinter haemorrhage
c) abnormalities of the nail plate e.g. discoloured nails, thickening of nails
sebaceous glands
- Sebaceous glands produce sebum via hair follicles (collectively called a pilosebaceous unit). They secrete sebum onto the skin surface which lubricates and waterproofs the skin.
- Sebaceous glands are stimulated by the conversion of androgens to dihydrotestosterone and therefore become active at puberty.
- Pathology of sebaceous glands may involve:
a) increased sebum production and bacterial colonisation e.g. acne b) sebaceous gland hyperplasia
sweat glands
Sweat glands regulate body temperature and are innervated by the sympathetic nervous system.
They are divided into two types: eccrine and apocrine sweat glands.
eccrine sweat glands
universally distributed
apocrine
Apocrine sweat glands are found in the axillae, areolae, genitalia and anus, and
modified glands are found in the external auditory canal. They only function from
puberty onwards and action of bacteria on the sweat produces body odour.
