Dermatology Flashcards
name 3 functions of the skin
Protection against environment Temperature regulation Neurological - Sensation Storage and synthesis - Vitamin D synthesis Immunosurveillance Stop fluid loss Aesthetics and communication
What cells in the skin present antigens and activate t-lymphocytes ?
langerhans
What are merkel cells
nerve endings for sensation
Function of melanocytes
produce melanin - pigment and protects nuclei from UV radiation induced DNA damage
the epidermis is made from?
keratinocytes (various levels of maturation)
2 types of sweat gland and function
eccrine (skin)
apocrine (axilla, anus, genitalia - only function from puberty, bacteria - body odour).
4 stages of wound healing
Haemostasis
Inflammation
Proliferation
Remodelling
What happens in the stages haemostasis and inflammation
Vasoconstriction and Pt aggregation (clot formation)
Vasodilation, migration NP and MP -> phagocytosis of debris
What happens in proliferation and remodeling
Granulation tissue formation (fibroblasts) and angiogenesis. Re-epithelialization
Collagen fibre-reorganisation, scar maturation
What might you use emollients for?
Rehydrate skin, re-establish surface lipid layer.
Use at dry, scaling conditions as soap substitute
SE of emollients
irritant - rash
Name 3 indications for topical corticosteroids
Anti-inflammatory, anti-proliferative
allergic/immune conditions, blistering, inflammatory skin conditions, connective tissue disease, vasculitis
4 strengths of topical corticosteroid cream - getting stronger
Hydrocortisone
Clobetasone butyrate (Eumovate)
Betamethasone valerate (Betnovate)
Clobetasol propionate (Dermovate)
Name 2 local SEs of topical corticosteroids
Skin atrophy, telangiectasia, striae, exacerbation skin conditions, acne, perioral dermatitis
Name 3 SEs od oral corticosteroids
SHIP DOC
Syndrome (Cushing’s) HTN Immunosuppression Psychosis Diabetes Osteoporosis Cataracts
Eg of topical Abx
Fusidic acid
mupirocin
neomycin
SEs of Abx. Name 3
Local (irritation, allergy)
Systemic: GI upset, rash, anaphylaxis, candidiasis, ABX associated infections
Eg of an oral retinoid
Isotretinoin, acitretin
Indication for oral retinoids . name 2
Acne, psoriasis, disorders of keratinisation
SEs of oral retinoids. Name 2
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)
What is the main SEs of ciclosporin? what should you do?
HTN and renal dysfunction
monitor BP and Ur + Cr
Ciclosporin is what kind of drug?
immunosuppressant
What type of drug is azathioprine? SEs?
Immunosuppressant
Hepatotoxicity and myelotoxicity
what is atopic eczema?
A chronic, relapsing inflammatory skin condition characterised by itchy, erythematous scaly patches.
Where is eczema usually in infants? older?
infants - face and extensor
Older
Flexor surfaces (skin folds)
What is needed for Dx of eczema
Itchy skin + 3 of
History of flexural involvement
Visible flexural dermatitis
Personal history asthma, hayfever (or family if <4)
Generally dry skin in last year
Onset at <2
What might you Ix in atopic eczema
Serum IgE levels,
allergy testing (specific IgE) = skin prick test or RAST (radioallergosorbant test)
Name 2 complications of eczema
Psychological stress
Bacterial superinfection (s.aureus)
Eczema herpeticum (vesicular, HSV) - emergency
SE of treatment
contact dermatitis usually comes with a Hx of contact with irritants / occupational Hx
(REMEMBER THE OSCE STATION YOU FUCKED)
How would you mx Irritant?
Allergic?
Irritant: emollients/topical corticosteroids + irritant avoidance (gloves)
Allergic: topical corticosteroids + allergen avoidance (±topical calcineurin… as AD)
The same basically
Seborrhoeic dermatitis is usually found where?
scalp, nasolabial fold, anterior chest
what is Seborrhoeic dermatitis called in children ? mx?
cradle cap (resolves by 12 months)
emollients and topical corticosteroidsif needed
Stress tends to flare Seborrhoeic dermatitis in adults. Mx of scalp?
non scalp?
What if it lasts >3/12?
(scalp only) -
- topical shampoo (salicylic acid - keratolytic, coal tar, antifungal - ketoconazole)
- topical corticosteroids
Adults (non-scalp)
topical corticosteroids ± topical antifungals (ketoconazole)
Lasting over 3 months - oral antifungal (ketoconazole)
Basically just topical corticosteroids - I’ve left the other stuff in so its recognisable in the MCQ)
What is psoriasis? Characteristic?
Inflammatory disease due to hyperproliferation of keratinocytes and inflammatory cell infiltrate
Seen on biopsy of psoriasis?Name 2 things
focal parakeratosis (retained nuclei,
absent granular layer),
epidermal acanthosis (thickening),
dilated capillaries
2 key associations with psoriasis
50% - nail changes
(pitting, Beau’s lines (horiz) and onycholysis - lift off bed)
10% have psoriatic arthritis
symmetrical polyarthritis, asymmetrical oligomonoarthritis
Most common form of psoriasis?
Plaque
Well-circumscribed, erythematous, scaly plaques with silver scaling
Bleed on scale removal/picking
(Auspitzs sign)
Where is/ appearance of guttate psoriasis ? Who gets it?
Raindrop like on trunk, arms and legs
post streptococcal tonsillitis @young
Mx of psoriasis
General Educate, avoid triggers (drug stress alcohol) emolllients Topical Topical corticosteoids Vid D analouges
Phototherapy (extensive disease)
Oral - Severe
Methotrexate
ciclosporin
acitretin
Biologic
etanercept, infliximab
guttate 1st line
phototherapy
Pustular psoriasis 1st line
oral retinoid (acitretin)
Complications of acne . Name 3
depression
Post-inflammatory hyperpigmentation, scarring, deformity, psychological
Mx of mild acne
Topical keratolytic Eg Benzoyl peroxide OR Topical retinoids Eg isoretinoin \+ Topical Abx if needed (clindamycin/erythromycin)
Mx of mod/severe acne
Topical retinoid + oral antibiotics - (tetracycline, doxycycline)
Anti-androgens (females) - COCP
Oral retinoids (severe only) - isotretinoin (see SE)
Which skin Ca has the highest reccurence and METS?
SCC (from keratinocytes)
BCC and SCC are keratinocytes, melanoma is melanocytes.
What cell are BCCs from?
hair follicle
Rfs for SCC
UV exposure, pre-malignant conditions (actinic keratoses, Bowen’s disease), chronic inflammation (leg ulcer), immunosuppression, whites, outdoor occupation, previous SCC
How would a SCC present?
Keratotic (scaly, crusty), ill-defined nodule ± ulceration± bleeding
What is bowens ?
Superficial red, scaley patch on skin
-Easy to treat
Whats the problem with SCC
SPREAD Quick growing, local metastases (quicker than BCC)m or spread to local LN
Ix for SCC
Biopsy
CT/MRI
What 3 levels of SCC can you see on biopsy?
Keratinocyte atypia - actinic keratosis
SCC-in-situ (Bowen’s) - full thickness atypia with intact basement membrane
Invasive tumour - penetrates bm to dermis
Common mets for SCC
LNs, lung, liver, brain, bone
Mx of SCC in situ
Cryotherapy (destructive), topical chemotherapy (fluoracil - Efudix)
Mx of <2cm invasive SCC
Wide surgical excision
Mx of mets
excision (if on skin) + radiotherapy
BCC RFs
UV exposure, sunburn at childhood, skin type I (burns), increasing age, male, immunosuppression, previous history, genetic predisposition, whites, albinism
How does BCC appear?
rodent ulcer
Seen on biopsy of BCC
small, dark staining (basophilic) basal cells growing in nests (aggregates), invading the dermis
pearly flesh coloured papule
Mx of BCC is usually
surgical (radiotherapy if needed)
What is Mohs micrographic surgery?
excision of lesion and tumour progressively until specimens are free of tumour
- good for high risk / reccurent
BCC/SCC
Non surgical option for low risk BCC
Cryotherapy
Photodynamic therapy
Topical fluorouracil
How do you describe a pigmented lesion ?
ABCDE Asymmetry Border Colour Diameter EVOLUTION!
Whats issue with melanoma
mets early
Rfs melanoma
Excess UV exposure, skin type I (always burns), history of multiple/atypical moles, Fam Hx, immunosuppression, previous melanoma
The most common type of melanoma is superficial spreading mealnoma
Where common? who ?
Appearance
Common on lower limbs
young and middle aged,
large + flat + irregularly pigmented,
grow laterally then invade deep
3 Ix for melanomas
Dermascopy -ABCDE
Biopsy
Assess mets
How big an area do you biopsy for melanoma? 2 descriptions?
Ideal biopsy is full thickness local excision with margins of 2mm
If confined to epidermis = melanoma in situ
If spread to dermis = invasive melanoma
Where is the common site of mets from melanoma?
liver and bone
3 methods of assing mets in melanoma
Sentinel lymph node biopsy
CXR and liver USS (liver and bony mets)
CT chest/abdo/pelvis
Mx melanoma in situ
Wide local excision / Mohs surgery
Mx melanoma
Surgical excision (wide local excision) ± sentinel lymph node biopsy
Complicationof surgery to lymph nodes
lymoedema
How is recurrence of melanoma assessed/
Breslow Thickness:
0.75mm = low risk0.75-1.5mm = medium risk>1.5mm = high risk
What is bullous pemphigoid
chinic blistering disorder usually affecting elderly
what causes bullous pemphigoid
autoantibodies against hemidesmosal antigens in epidermis and dermis
Ix for bullous phphigoid
biopsy for histopathology
Mx of bullous pemphigoid
General
Wound dressing, monitor for infection
Topical
Corticosteroids
Oral (for widespread)
Steroids (pred) + antihistamines (hydroxyzine
Nicotinamide + oral tetracycline
immunosupressives
pemphigus vulgaris is what?
Cause?
Autoimmune blistering skin disorder affecting the middle aged
Autoantibodies against antigens in epidermis
(shallower than bullous)
Mx pemphigus vulgaris
General wound dressing, monitor for infection
Oral
High dose oral steroids, immunosupressants
What is this Golden crust or vesicles/bullae in bullous?
Who gets it and cause?
impetigo
children
s aureus
(very contagious)
What makes you more susceptible to impetigo?
trauma
skin breaks - eg eczema
mx impetigo
Topical fusidic acid
Intranasal mupirocin
Oral flucloxacillin
2 types of herpes and where it affect? mx?
Type 1 = oral herpes - oral ulcer with vermillion border or vesicles
Type 2 = genital herpes
Treat with aciclovir - oral ± topical
Mx of orbital cellulitis
Ceftriaxone (IV) + vancomycin (IV) ± orbital decompression
As risk of blindness / abscess
What causes scalded skin? seen in who?
commonly seen in children caused by production of a circulating epidermolytic toxin from benzylpenicllin-resistant (coagulase positive) staphylococci
All over body - DEHYDRATION IS MASSIVE PROBLEM
Mx of scladed skin
analgesia, antibiotics (IV then oral) + fluids
Flucloxacillin
Ix and Mx of fungal infections
Establish Dx
- with skin scrapings, swabs or hair/nail clippings (dermatophytes)
Treat precipitating factors
-Immunosuppressives, moisture
Topical antifungal
- E.g. terbinafine cream, ketoconazole/selenium sulphate shampoo
Oral antifungal
- E.g. itraconazole, fluconazole
Why should you avoid topical corticosterids in fungal infections
causes tinea incognito
Cause of warts
HPV (6-11) - fleshy condylomata accumulata
Mx of warts
Cryotherapy, silver nitrate, debridement and salicylic acid
What does this describe : Pearly, smooth papule with a central umbilication commonly distributed at face and groin
Mx?
molluscum contagiosum
curettage, cryotherapy
What causes scabies
Infection with mites
Mx of scabies
Treat the whole family + wash clothes >60 degrees
Topical permethrin (5%) + antihistamines: apply from neck down and wash after 8 hours
what 3 things do you check in all ulcers
Site
Edge
Base
What causes venous ulcers
chronic venous insufficiency, immunosuppressed, HF, anyone with poor healing.
What are the signs of chronic venous insufficiency?Name 3
Ulcers
Ankle swelling, hyperpigmentation, lipodermatosclerosis (bound down), heavy legs, dry/scaly skin, telangiectasias, varicose veins, itching
Rfs for venous insufficiency
Age, family history, smoking, DVT, orthostatic occupation
Where are venous ulcers usually
Medial/lateral malleolus.
Between knee and ankle
Appearance of venous ulcers
Large Shallow/sloping edge Painless/mild pain (relieve by elevation) Irregular border Moist granulating base
Ix for venous ulcers ?
ABPI using Doppler for pulses - to exclude arterial
Measure surface area, examine edge, base and note location. Examine other leg
Swabs for microbiology - if signs cellulitis
when to biopsy venous ulcers
if atypical appearance or fail to heal in 12 weeks
Mx of venous ulcers ? When would you give Abx?
Graduated compression + leg elevation (exclude art and neuro!)
- Maximise pressure at ankle/gaiter and decrease as higher. Helps control venous insufficiency
Debridement and cleaning - debride slough
Dressing
- Occlusive hydrocolloidal - allows epthelial migration and influx of leukocytes and moisture
ABX if cellulitis suspected
Cause of arterial ulcers?
atherosclerosis and tissue hypoxia
When would you suspect arterial ulcer?
CV RFs (smoking, DM etc), absent pulses, features of ischaemia
More distal site
painful
grey granulating base
Features of ischemia
pale, pulseless, perishingly cold, parasthesia, paralysis
How to identify peripheral arterial disease?
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
What is key difference in mx of venous vs arterial
NO compressing in arterial
Where do you get neuropathic ulcers?
bottom of foot - pressure points - hallux
Mx of neuropathic ulcers
Seek cause of neuropathy (often diabetes)
Diabetic foot management (socks/shoes/pressure/clean/check sensation)
How does urticaria present\/
itchy wheals - central swelling with peripheral eythema
What causes urticaria? Mx?
increase in permeability of capillaries and venules mediated by histamine derived from skin mast cells
antihistamines
What is angioedema
Swelling of tongues, eyelids and lips
Complications of angioedema
Asphyxia, cardiac arrest and death
Not good
Can get an urticarial rash with it which gives you itchy wheels
- IgE mediated with mast cells and histamine
- anti-histamines are treatment and oral corticosteroids
3 hallmarks of anaphylaxis
Bronchospasm (stridor - beware)
Facial and laryngeal oedema
Hypotension
Mx of 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
mx of chronic urticaria
Loratadine
What is erythema nodosum?
Erythematous lumps form on shins due to inflammation of subcutaneous fat
Causes of erythema nodosum?
Inflammatory bowel disease (UC/Crohn’s)
TB (primary infection)
Throat infection (strep)
Sarcoidosis (assoc with enlarging LNs in lung)
What is erythema multiforme ? Usual cause / prognosis
Hypersensitivity reaction triggered by infection.
Acute , self limiting - usually HSV
Describe the appearance of erythema multiforme
few - 100s of lesions
Target lesions
1 -Outer - bright red
2- Middle - pale pink, oedematous and raised
3- Inner - dusky/dark red with blister/crust
What causes stevens johnson syndrome?
Preceding history of medication use or infection: anticonvulsants, ABX, NSAIDs
(think antiretroviral man in Uganda who fucked it)
toxic epidermal necrolysis is basically more severe form of steven johnson.
What characterises them?
Detachment of epidermis from dermis manifesting as maculopapular rash and bullae (keratinocyte apoptosis) -> Nikolsky sign (sloughing at pressure
Dx of SJS / TEN?
skin biopsy and histopathology
Mx of SJS / TEN
Call for help Withdrawal of causative agent Dressing and topical antibacterial and emollients IV fluids Analgesia
Complicatios of SJS? TEN
Dehydration, infection and sepsis, multi-organ failure
What is necrotising fascitis? cause?
Rapidly spreading infection of deep fascia with secondary tissue necrosis
Group A haemolytic strep (pyogenes)
Staph aureus
[couple others too eg Pseudomonas aeruginosa)
Rfs for nec fasc
Abdominal surgery, diabetes, malignancy
Presentation of nec fasc
SEVERE PAIN
Erythematous, blistering, necrotic skin
Systemically unwell - fever and tachycardia
Crepitus - subcutaneous emphysema
Mx nec fasc
Surgical debridement and haemodynamic support
Empirical broad spectrum ABX e.g. vancomycin and tazocin
How does rosacea present?
Flushing, dilated telangiectasia (facial), facial erythema, inflammatory papules
Chronic skin condition affecting nose, cheeks and forehead and it is SYMMETRICAL
Triggers of rosacea ? name 2
Climate (sunshine), chemical/ingested agents (alcohol), stress, hot baths/drinks
Mx rosacea
Topical antibiotic/anti-inflammatory ± oral antibiotic
- Metronidazole/azelaic acid (top)
- Doxycycline/tetracycline (oral)
What is being described?
Common, multiple, benign lesions affecting over 50s (80-100%)
STUCK-ON lesions, well-circumscribed plaques or papules, may be warty appearance, grey-brown-black, painless
Seborrhoeic keratosis/basal papilloma
Where is Seborrhoeic keratosis/basal papilloma usually found? associations?
torso / head
UV sun damage, white
Mx of Seborrhoeic keratosis/basal papilloma
Itchy - steroids (topical)
Flat - cryotherapy
Raised - curettage or cautery
What is lichen planus?
Who normally gets it?
A self-limiting inflammatory disease affecting skin (+genitals), nails, hair and mucous membranes
middle aged women
Mx of lichen planus
Cutaneous Topical corticosteroid (clobetasol) + antihistamine (e.g. chlorphenamine)
Oral
Topical corticosteroid ± oral corticosteroid
Genital
Topical corticosteroid/calcineurin inhibitor
2ndary causes of systemic itch. Name 2 non malignant and 2 malignant
Renal - CKD caused by urea
Cholestatic - bile salts
haematological - basophils / mast cells
endocrine
hyper/hypo thyroid , DM
Malignant
Hodkin - bradykinin
carcinoid syndrome - serotonin
What 2 orgas usually hit by vasculitis
kidneys skin
What is alopecia
autoimmune affecting hair follicles
3 types of alopecia?
Patchy alopecia areata
Alopecia totalis (scalp)
Alopecia universalis - all body hair
mx of alopecia?
Limited= topical corticosteroid + cosmetic camouflage and support or intralesional corticosteroid
Extensive = topical immunotherapy + cosmetic camouflage + support
Pemphigus vs pemphigoid
pemphigus goes bust
[between epidermis and dermis so close to surface]
-Blisters pop v early so don’t tend to see them
pemphigoid is deeper so blisters tend to last
Layers of the skin
epidermis
dermis - mainly connective tissue produced by fibroblasts (inc hair follicles, sweat glands and nerve endings)
fat cells
Se of topical steroids - give 3
thinning of skin bruising and tearing of skin telangiestasia trigger other skin conditions allergy
pyoderma gangrenous
IBD
small red papule becoming necrotic ulcer
Treatment of erythroderma
WET WRAPS
20-40% fatality
