dermatology Flashcards
Describing a rash
DCM!
D = distribution - skin folds/flexural
C = configuration (grouping) - linear, annular (ring), discoid (coin like), cluster
M = Morphology - cyst/fissue/macule/papule/polyp/pustule/nodule
define macule
flat (non-palpable) are of altered colour <0.5cm eg freckle
define patch
Flat area of altered colour >0.5cm e.g. port-wine stain
define papule
Solid raised lesion <0.5cm e.g. xanthomata
define nodule
Solid raised lesion >0.5cm with deeper component e.g. granuloma
define plaque
Flat, palpable, raised scaling lesion, well circumscribed e.g. psoriasis
define vesicle
Raised, clear, fluid filled lesion <0.5cm e.g. HSV
define bulla
Raised, clear, fluid filled lesion >0.5cm
define pustule
Pus containing lesion <0.5cm e.g. acne
define abscess
Localised accumulation of pus in dermis or subcutaneous e.g. periungual
define wheal
Transient, raised lesion due to dermal oedema e.g. urticaria
define boil
Staphylococcus infection around or within hair follice
define secondary excoriation
Loss of epidermis following trauma e.g. eczema
define lichenification
Well-defined roughening of skin with attenuation of skin markings
define scale
flakes of stratum corneum e.g. psoriasis (silver scaling)
define crust
Rough surface of dried blood, serum or bacteria e.g. burst blister
define scar
New fibrous tissue occurring post wound healing, may be atrophic (thinning), hypertrophic (hyperproliferation within boundary), or keloidal (beyond boundary)
define ulcer
Loss of epidermis and dermis
define fissure
Epidermal crack due to excess dryness, e.g. eczema
define striae
Linear areas, purple, pink, or white e.g. steroids
layers of skin
top to bottom:
1 - epidermis
2 - dermis
3 - subcutaneous layer
function of normal skin
Protection against environment Temperature regulation Sensation Vitamin D synthesis Immunosurveillance Stop fluid loss
epidermis 4 main cell types
- Keratinocytes - produce keratin (protective layer)
- Langerhans’ cells - present antigens and activate T-lymphocytes
- Melanocytes - produce melanin - pigment and protects nuclei
from UV radiation induced DNA damage - Merkel cells - Special nerve endings for sensation
what do the 4 layers of the epidermis represent
the different stages in maturation of the keratinocytes
4 layers of epidermis
brown slugs grab cocks - excuse my french tehe - bottom to top
1. Stratum basale (basal) - actively dividing cells
2. Stratum spinosum (prickle) - differentiating cells
3. Stratum granulosum (granular) - cells lose nuclei, contain granules of keratohyaline, secrete lipid to extracellular space
3a – Stratum lucidum - paler compact keratin - only at thick skin (sole)
5. Stratum corneum (horny) - layer of keratin
what does the dermis consist of?
Dermis made up of collagen (mainly), elastin and glycoaminoglycans (GAG) - synthesised by fibroblasts.
Also contains immune cells, nerve cells, skin appendages, lymphatic/blood vessels
problems with epidermis and dermis
epidermis - Increased turnover (psoriasis), changes in surface/loss (scales, crust), changes in pigmentation
dermis - Changes in contour (papules, nodules), disorders of appendages (hair/acne), lymphatic and bv problems (erythema - vasodilation, purpura - capillary leak)
Hair-
types?
structure?
3 types-
- lanugo - fine,
- vellus - body,
- terminal - coarse i.e. scalp, eyelash)
structure -
made of modified keratin, divided into shaft (keratinised tube) and bulb (actively dividing cells and melanocytes)
Nails
Made of nail plate (hard keratin) arising from matrix at posterior nail fold and rests on nail bed (contains capillaries)
Pathology: matrix (pits + ridges), bed (splinter haemorrhages), plate (thickened + discoloured)
therapies
medical
physical
FTU
MEDICAL - topical or systemic Deliver Rx to affected area and reduces SE side effects. Suitable at local + less severe. Active constituent transported to skin by base. FORMS Lotion - liquid Cream (oil in water) Gel (polymers in liquid) Ointment (oil with little water) Paste (powder in ointment)
PHYSICAL
cryotherapy, phototherapy, photodynamic therapy, laser/surgery
FTU - finger tip unit - crease to top = 0.5g
emollients indications directions SE examples
indications
Rehydrate skin, re-establish surface lipid layer. Use at dry, scaling conditions as soap substitute
directions
In direction of hair liberally
SE
Irritant - rash
eg Aqueous cream, emulsifying ointment, liquid paraffin (all 500g/tub) Diprobase (cream) Double base (gel) Dermol (antibacterial)
topical/oral corticosteroids
least -> most potent
when used
- Hydrocortisone (YOU BET DERM)
- Clobetasone butyrate (Eumovate)
- Betamethasone valerate (Betnovate)
- Clobetasol propionate (Dermovate)
Come in 30g tubes (enough to cover whole body once)
Anti-inflammatory, anti-proliferative
allergic/immune conditions, blistering, inflammatory skin conditions, connective tissue disease, vasculitis
topic steroid SE
Skin atrophy, telangiectasia, striae, exacerbation skin conditions
acne, perioral dermatitis
topical abx examples +SE
Fusidic acid, mupirocin, neomycin
Local (irritation, allergy)
Systemic: GI upset, rash, anaphylaxis, candidiasis, ABX associated infections
oral retinoids
examples
indications
SE
Isotretinoin, acitretin
indications:
Acne, psoriasis, disorders of keratinisation
SE
Mucocutaneous reactions: dry skin, lips, eyes
Disordered liver function (LFT)
Hypercholesterolaemia (Blood test)
Myalgia, arthralgia, depression
Teratogenicity (effective contraception one month before, during and after isotretinoin, 2 years after acitretin)
ciclosporin + tacrolimus
what are they
SE
Calcineurin inhibitors
SE - HTN and renal dysfunction
monitor BP and Ur + Cr
azathioprine
what is it
how does it work
SE
Pro-drug for mercaptopurine
Inhibits enzymes required for DNA synthesis of T and B cells
SE:
Hepatotoxicity and myelotoxicity
contact dermatitis pres types ix mgmt
pres
History of contact with irritants and occupational history
Localised burning, stinging, itching, blistering, redness, swelling at area of contact
types
Irritant - direct toxicity without prior sensitisation
Allergic - delayed hypersensitivity (history of atopy)
ix
Patch testing may identify agent
mgmt
Irritant: emollients/topical corticosteroids + irritant avoidance (gloves)
Allergic: topical corticosteroids + allergen avoidance (±topical calcineurin… as AD)
seborrhoeic dermatitis
pres
mgmt
pres
Pruritic, erythematous, scaly patches on scalp, nasolabial fold,
anterior chest
Infant - cradle cap (resolves by 12 months)
Adult - Flares with stress. Uninflamed scalp form is dandruff
or pityriasis capitis (fungus pityrosporum ovale)
mgmt
Infants - emollients and topical corticosteroids
Adults (scalp only) - topical shampoo (salicylic acid - keratolytic, coal tar, antifungal - ketoconazole) or topical corticosteroids
Adults (non-scalp) - topical corticosteroids ± topical antifungals (ketoconazole)
Lasting over 3 months - oral antifungal (ketoconazole)
types of cancer
melanoma - 10%
non -melanoma:
1. BCC - 70% - hair follicle, mets rare, low recurrance
2. SCC - 20% - keratinocytes, premalignant = actinic keratosis, in-situ - bowen’s, METS common, high recurrance
approach to describing pigmented lesion
ABCDE Asymmetry Border Colour Diameter EVOLUTION!
breslows thickness and clarkes level
assessing MM
Breslow’s thickness = depth of invasion, measured on histology
Thin = 1mm
Intermediate = 1-4mm
Thick = 4mm
Clark’s level = less accurate measure of tumour thickness
bullous pemphigoid what is it causes pres ix mgmt
what is it
A chronic blistering (sub-epidermal) skin disorder normally affecting the elderly
Caused by autoantibodies against hemidesmosal antigens in epidermis and dermis = sub-epidermal split in skin
pres
Tense fluid filled blisters on erythematous base
Often itchy and presents on trunk and limbs.
Symmetrical and favour flexures
Preceded by nonspecific itchy rash
ix
Skin biopsy for histopathology
Sub-epidermal blister with dermal inflammatory cell infiltrate rich in eosinophils
mgmt
General measures:
Wound dressing, monitor for infection signs
Topical therapies (for localised):
- Corticosteroids
- Tacrolimus
Oral therapies (for widespread lesions):
1. Steroids - prednisolone (short term) + sedating antihistamines - hydroxyzine
2. Nicotinamide (B3) + oral tetracycline
3. Immunosuppressives (azathioprine, methotrexate, ciclosporin)
pemphigus vulgaris
what is it
mgmt
Autoimmune blistering skin disorder affecting the middle aged
Autoantibodies against antigens in epidermis causing intra-epidermal split in skin (shallower)
Flaccid easily ruptured blisters forming erosions and crusts (painful)
Affects mucosal areas
Management
General measures - wound dressing, monitor for infection, oral care
Oral therapies - high dose oral steroids, immunosuppressants (methotrexate, azathioprine, cyclophosphamide, mycophenolate mofetil)
impetigo who pres cause mgmt
Common in children
Golden crust or vesicles/bullae in bullous impetigo
S.aureus
Susceptible post trauma/skin breaks e.g. eczema
Highly contagious
Treat with antibiotics
Topical fusidic acid
Intranasal mupirocin
Oral flucloxacillin
herpes simplex
types
mgmt
Type 1 = oral herpes - oral ulcer with vermillion border or vesicles
Type 2 = genital herpes
Treat with aciclovir - oral ± topical
warts aka def cause mgmt
aka
Verrucae vulgaris
def Elevated, round, hyperkeratotic skin papules with rough grey or brown surface
cause
HPV (6-11)
mgmt
Cryotherapy, silver nitrate, debridement and salicylic acid
molluscum contagiosum
cause
pres
mgmt
Viral - affects 20% children
Acquired through skin to skin contact, sexually in adults
Pearly, smooth papule with a central umbilication commonly distributed at face and groin
Manage children expectantly. Avoid sharing towels/clothing
Adult STD: curettage, cryotherapy
scabies causes pres dx mgmt
Caused by infection with mites, transmission via skin to skin contact. Often seen in overcrowded living conditions
Pruritus, erythematous papules, linear burrows in interdigital web space
dx
Confirmed by microscopic visualisation of mites, eggs, faeces in skin scrapings
mgmt
Treat the whole family + wash clothes >60 degrees
Topical permethrin (5%) + antihistamines: apply from neck down and wash after 8 hours
ulcer
def
what do you check?
most common
Abnormal breaks in the epithelial surface
Need to check 3 things in all ulcers
- Site
- Edge
- Base
Most common ulcers are venous (80%), then arterial (20%)
pathophys of venous ulcers
Chronic venous insufficiency (affects 7% of population)
Incompetent valves in veins of lower leg
Blood squeezed into superficial veins rather than to heart -> dilation (varicosities) and raised pressure
Raised pressure -> oedema, venous eczema and extravasation of fibrinogen
Extravascular fibrin deposition
Poor oxygenation of surrounding skin + ulceration
venous ulcer site appearance ix mgmt
Medial/lateral malleolus. Between knee and ankle
appearance Large Shallow/sloping edge Painless/mild pain (relieve by elevation) Irregular border Moist granulating base
ix
ABPI using Doppler for pulses - to exclude arterial
Measure SA
Swabs for microbiology - if signs cellulitis
Biopsy if atypical appearance or fail to heal in 12 weeks
mgmt
Graduated compression + leg elevation (exclude art and neuro!)
Maximise pressure at ankle/gaiter and decrease as higher.
Debridement and cleaning - debride slough
Dressing - Occlusive hydrocolloidal - allows epthelial migration and influx of leukocytes and moisture
ABX if cellulitis suspected
arterial ulcers causes suspect if site appearance ix mgmt
causes
atherosclerosis
tissue hypoxia
suspect if
CV RFs
6 ps
site
more distal
dorsum of foot or toes
appearance
Painful, initially irregular edge (may become more clear), grey granulating base, no bleeding on debridement, punched out, cold shiny surrounding skin
ix
ABPI: BP cuff on lower calf above ankle. Doppler probe on dorsalis pedis. Divide systolic at ankle by arm (highest) -> <0.9 implies peripheral arterial disease
mgmt
vascular surgeon problem lol
neuropathic ulcers
site
appearance
mgmt
Under callouses or over pressure points (plantar aspect of 1st and 5th metatarsophalangeal joint
Punched out + deep sinus
Surrounded by chronic inflammatory tissue
Probing and debridement leads to brisk bleeding
Painless
Sloughy/necrotic base
mgmt
Seek cause of neuropathy (often diabetes)
Diabetic foot management (socks/shoes/pressure/clean/check sensation)
mgmt of urticaria, angioedema, + anaphylaxis
Acute urticaria ± angioedema with airway involvement
->IM adrenaline (1 in 1000) + airway protection + IV antihistamines (chlorphenamine/dipenhydramine = 2nd generation) + IV corticosteroids (hydrocortisone) + trigger identification + avoidance
Acute urticaria ± angioedema without airway involvement
2nd gen antihistamine, H1 receptor antagonist - (e.g. loratadine, non sedating) + systemic corticosteroid (prednisolone) + trigger avoidance
Chronic urticaria
Loratadine
anaphylaxis
adult - 0.5mg 1:1000 adrenaline, 200mg hydrocortisone, chlorphenamine 10mg
6-12 - 0.3mg, 100mg, 5mg
<6 - 0.15mg, 50mg, 2.5mg
rosacea def pres triggers mgmt
def Common chronic skin condition affecting convexities of face + forehead
pres
Flushing, dilated telangiectasia (facial), facial erythema, inflammatory papules
Prominent sebaceous glands - fibrosis and rhinophyma
Ocular - blepharitis
triggers
Climate (sunshine), chemical/ingested agents (alcohol), stress, hot baths/drinks
mgmt
Topical antibiotic/anti-inflammatory ± oral antibiotic
- Metronidazole/azelaic acid (top)
- Doxycycline/tetracycline (oral)
seborrhoeic keratosis def pres location assoc mgmt
Common, multiple, benign lesions affecting over 50s (80-100%)
pres
STUCK-ON lesions, well-circumscribed plaques or papules, may be warty appearance, grey-brown-black, painless
loc
Torso or head
assoc
UV sun damage, white
Milia-like cysts and comedone-like openings
mgmt
Itchy - steroids (topical)
Flat - cryotherapy
Raised - curettage or cautery
lichen planus what is it location pres mgmt
A self-limiting inflammatory disease affecting skin (+genitals), nails, hair and mucous membranes. Most common in middle aged women. Associated with intense pruritus (80%) and scarring alopecia
Characteristic eruption:
Itchy, shiny, flat-topped violaceous papules and plaques
Location:
Extremities
Visible at mucosa/cutaneous lesions
Wickham’s striae (overlying lacy white network) and oral erosions
mgmt
Cutaneous
-> Topical corticosteroid (clobetasol) + antihistamine (e.g. chlorphenamine)
Oral
-> Topical corticosteroid ± oral corticosteroid
Genital
-> Topical corticosteroid/calcineurin inhibitor
ddx of itch
Renal pruritus (chronic renal failure) - Urea mediated
Cholestatic pruritus = Bile salt mediated
Haematological pruritus (polycythaemia vera)- increased number basophils and mast cells in skin
Endocrine pruritus - hyper (kinin) /hypothyroidism (xerosis), DM
Malignant pruritus:
1. Hodgkin lymphoma - bradykinin mediated
2. Carcinoid syndrome - serotonin mediated
vasculitic skin changes
Vasculitis commonly affects the skin and the kidneys: therefore do a urine dip
Think of cutaneous vasculitis when on renal/cardiovascular
Small vessels: purpura, petechiae, ulcers
Medium vessels: nodules and livedo reticularis
alopecia areata what is it assoc types pres ddx mgmt prog
Autoimmune disease: inflammatory cells (T-lymphocytes) target hair follicles - preventing growth
Common disorder - affects 2% of population. Strong association HLA (class 2). May be family Hx of AI disease
Small round patch of hair loss which may regrow spontaneously.
Patchy hair-loss. In non-scarring follicular markings/orifices are retained -> consider reversible. Exclamation mark hairs (narrower near skin). Positive hair pull test (>5 hairs)
Types:
Patchy alopecia areata
Alopecia totalis (scalp)
Alopecia universalis - all body hair
ddx
Scarring alopecia. Lack of follicular markings + inflammation, scale and erythema. On biopsy = lymphocyte or neutrophil infiltrate
mgmt
Limited= topical corticosteroid + cosmetic camouflage and support or intralesional corticosteroid
Extensive = topical immunotherapy + cosmetic camouflage + support
prog
Relapses. In 2 years most will have spontaneous regrowth
androgenic alopecia aka what is it inheritance pattern mgmt ix
Genetically determined patterned progressive hair loss from scalp.
Dominantly inherited with variable penetrance therefore family Hx relevant.
Men (onset 20-25):
Progressive shortening of anagen phase with increased telogen phase.
Androgen (DHT) mediated follicular miniaturisation -> fine, short, non-pig vellus hair
Testosterone to DHT by 5-alpha-reductase
Pattern: receding frontal hairline, thinning in temporal areas progressing to crown
Rx = topical minoxidil ± oral finasteride (not for women) ± cosmetic aids (minoxidil = 3/6 months see some growth)
Women (onset menopause, assoc PCOS):
Diffuse thinning on crown but preservation of frontal hair line
Ix: Hair pull (<3 hairs - areata), TFT (hyperthyroidism), dermatoscopy (follicular miniaturisation)
