Dermatology Flashcards
What are the layers of the skin?
Come Lets Get Sun Burnt Stratum Corneum Stratum Lucidum Stratum Granulosum Stratum Spinosum Stratum Basale Dermis
What are the cells that give skin its pigmentation, and which layer are they found in?
Melanocytes
Stratum basale
When describing skin lesions, what pattern should be followed?
DCM:
Distribution
Configuration
Morphology
What conditions are associated with the following distribution patterns? Flexures Extensors Face Dermatomal Symmetrical
Where on the body it is: Flexures: eczema Extensors: psoriasis Face: seborrheic Dermatomal: shingles
Pattern
Symmetrical: vitiligo
Which conditions are the following configurations associated with? Linear Targeted Annular Discoid Reticular
Linear: Koebner phenomenon (eg psoriasis) Targetoid: Erythema multiforme Annular: tinea, lupus Discoid: discoid lupus, discoid eczema Reticular: livedo reticularis
Give 4 words for describing the morphology of a skin lesion
Macule Papule Plaque Nodule Vesicle Crust Scale
What is the most important diagnosis to consider with any type of skin lesion?
Cancer
What are the Fitzpatrick skin types?
I - never tans, always burns (red hair, freckles)
II - usually tans, always burns
III - always tans, sometimes burns (dark hair, brown eyes)
IV - always tans, rarely burns (olive skin)
V - sunburn and tan after extreme UV (brown skin)
VI - black skin, never tans/burns
Give 4 RFs for BCC
UV exposure - elderly (over long timeframe)
Fair skin (fitzpatrick 1/2)
Immune suppression
Genetic susceptibility
Give 4 features of a BCC
Shiny 'pearly' surface Telangiectasia Central nodule Surface ulceration Rolled edge Locally invasive - do not metastasise Slow-growing
Management of BCC?
Excision (Moh’s micrographic surgery)
Radiotherapy
Give 4 RFs for malignant melanoma
UV light exposure Fair skin (fitz 1/2) Red hair >100 naevi on body >5 atypical naevi FHx
What are the features of malignant melanoma?
ABCDE Asymmetrical Border irregularity Colour irregularity Diameter >6mm Evolving
What is the most common type of melanoma?
Give 3 other types
Superficial spreading
Nodular
Lentigo maligna
Melanoma of the nails
What is the most important prognostic indicator for malignant melanoma?
BRESLOW THICKNESS
Thickness of melanoma - measured from granular layer down to deepest part of invasion
Used in TNM staging
Thicker = worse prognosis
How is malignant melanoma treated?
Excision
Chemo, radio and immunological therapy for palliative patients with widely metastatic disease
Where do malignant melanomas commonly metastasise to?
Lungs
Brain
Give 4 RFs for SCC
UV light exposure over long timeframe
Immune suppression
Actinic keratoses and Bowen’s disease
Smoking
Long-standing leg ulcers (Marjolin’s ulcer)
Genetic conditions - albinism, xeroderma pigmentosum
What are the features of SCC?
High risk sites - lips and ears
Keratotic appearance
Potential to metastasise
How are SCCs treated?
Surgical excision (4mm margins if <20mm, 6mm margins if >20mm)
Moh’s micrographic surgery may be used in high-risk patients and in cosmetically important sites
What are the 3 types of ulcers seen on the skin?
Arterial
Venous
Neuropathic
Give 4 features of a venous ulcer
Commonly over medial malleolus Varicose veins Haemosiderin patches/deposits in skin Lipodermatosclerosis Venous eczema (dry and shiny)
Due to venous insufficiency
How are venous ulcers managed?
Compression bandages
DO NOT USE IF ABPI <0.9
If this doesn’t work, consider referral to vascular surgeons
What is the most important investigation to perform for skin ulcers?
ABPI
Normal is 0.9-1.2. DO NOT USE COMPRESSION BANDAGES IF <0.9 as sign of arterial disease and could lead to critical limb ischaemia
Give 4 features of arterial ulcers
Peripherally located - distal points, pressure sites Deep, punched out, necrotic Painful Shiny skin Increased CRT May not be able to feel pulses in feet Signs of hypoperfusion RFs for arterial disease present Abnormal ABPI
How are arterial ulcers managed?
Referral to vascular surgeons for revascularisation surgery
Exercise (build up collateral blood supply)
Modify cardio RFs
Give 4 features of neuropathic ulcers
Plantar surface of metatarsal head and hallux
Occur on pressure sites
Punched out/necrotic
Sensory impairment to area
How are neuropathic ulcers managed?
Education on diabetic foot health to prevent
Cushioned shoes to reduce callous formation
What are some triggers/causes of eczema?
Dry skin
Hot/cold
Irritants
Allergy
How does eczema present?
Patches of dry, red, itchy skin on flexor surfaces
(face and trunk in babies)
If contact dermatitis: specific pattern depending on where on body the patient is exposed
Management of eczema?
EMOLLIENTS
Topical steroids for acute flares
Steroid sparing agents
Give some examples of steroid sparing agents that may be used in treating eczema
Topical calcineurin inhibitors (tacrolimus)
Antihistamines
2nd line systemic agents (e.g. methotrexate)
What is eczema herpeticum?
LIFE THREATENING EMERGENCY
Skin infection (HSV 1/2)
More common in children with pre-existing eczema
May have s.aureus superinfection, leading to impetigo
Management of eczema herpeticum?
Admit to hospital
IV Aciclovir
What is psoriasis?
Chronic skin condition - scaly plaques form on extensor surfaces of the body
Can also affect scalp and nails
What is the most common type of psoriasis?
Give 6 other types
Chronic plaque psoriasis
Flexure psoriasis (ask about genitals) Scalp Guttate Palmar-plantar Nail Generalised pustular (hospitalisation may be needed)
Give 3 nail features of psoriasis
Pitting
Onycholysis (nail separating from skin beneath)
Thick/hyperkeratotic nails
What is the term for when psoriasis spreads to an area of skin that has been broken?
Koebner phenomenon
How is psoriasis managed?
Emollients
Topical steroids + Vit D analogues (e.g. calcitriol)
UV light therapy
Systemic therapies (retinoids, MTX, ciclo)
Biologics (Infliximab, adalimumab)
What are the corticosteroids that may be prescribed in psoriasis? (list in increasing order of strength)
HI YOU BET DERM Mild: Hydrocortisone Mod: Eumovate Potent: Betnovate V potent: Dermovate
What are 2 extra-dermal complications of psoriasis?
Psoriatic arthritis
Increased risk of cardiovascular disease
Patient with sore throat for the last few days. Presents with raindrop shaped plaques with silvery scale on their trunk. Likely diagnosis?
Guttate psoriasis
What is the typical trigger for guttate psoriasis?
Strep throat (Group A Streptococcus)
How is guttate psoriasis investigated and treated?
Ix: throat swab for anti-streptolysin O titre
Rx: most self-resolve in 2-3 months, topical agents (like normal psoriasis)
What is the causative organism of acne vulgaris?
Propionibacterium acnes
What are the features of acne?
Comedones (dilated sebaceous follicles) Papules Pustules Nodules Cysts Scarring - ice pink, hypertrophic
Management of acne vulgaris?
1) Single topical therapy (retinoids or benzyl peroxide)
2) Topical combination (tetracycline + stage 1 topical)
3) Oral Abs (oxytetracycline/doxycycline)
4) Oral isotretinoin
What are some side effects of isotretinoin? (Roaccutane)
Dry skin Depression LFT derangement Increased serum triglycerides Teratogenic Hair thinning Nose bleeds Idiopathic intracranial hypertension Photosensitivity
What is Wallace’s rule of 9s for burns?
Head = 9 Arm = 9 each Torso = 9 front, 9 back Abdo = 9 front, 9 back Leg = 9 front, 9 back
What are the different gradings for burns?
1) Superficial - red, painful
2) Superficial dermal - red, painful, blistered
3) Deep dermal - decreased sensation, white, blistered
4) Full thickness - white, no pain, no blisters. May have muscle/bone involvement
What is the Parkland formula for burns?
Fluid requirement in burns victims over 24h. Fluid requirement (ml) = TBSA% x weight (kg) x 4
TBSA = total body surface area affected
How are burns managed?
ABCDE Stop the burning Layered clingfilm Monitor U+Es Emollients (if superficial) Escharotomy if circumferential Appropriate analgesia Non-adherent dressing
What are some indications for burns to be referred to secondary care?
Affects face, neck, hands, feet or genitals Deep dermal/full thickness Smoke inhalational injury Chemical/electrical Non-accidental injuries
What are the features of acne rosacea?
Flushing
Telangiectasia
Affects nose, cheeks, forehead
Persistent erythema with papules and pustules
Rhinophyma
Ocular involvement - blepharitis, keratitis, conjunctivitis
What is rhinophyma?
Large, bulbous nose associated with granulomatous infiltration, commonly due to untreated rosacea
Management of acne rosacea?
Metronidazole (topical) Oxytetracycline (systemic antibiotics) Daily suncream Camouflage cream Laser treatment for telangiectasia Surgical repair of rhinophyma
What is bullous pemphigoid?
Autoimmune, sub-epidermal blistering of skin Affects elderly patients Itchy, tense blisters Typically around flexures Usually heal without scarring Mouth spared
What would you see on biopsy of bullous pemphigoid?
IgG and C3
How is bullous pemphigoid managed?
Refer to derm - biopsy to confirm diagnosis
Oral corticosteroids
What is vitiligo?
Autoimmune disease
Loss of melanocytes leading to depigmentation
Affects 1% population
Commonly presents 20-30yrs
How is vitiligo managed?
Sunscreen for affected areas
Camouflage makeup
Topical corticosteroids (may reverse changes if applied early)
Role for tacrolimus and phototherapy
Give 5 diseases associated with vitiligo?
T1DM Addison's Pernicious anaemia Autoimmune thyroid disease Alopecia areata
What is alopecia areata? What would you see?
Autoimmune, localised hair loss
Well-demarcated patches
May be small broken ‘exclamation’ hairs
How is alopecia areata managed?
Hair tends to regrow in 50% by 1 year - need to explain this to patient
Treatments: Topical steroids Topical minoxidil Phototherapy Contact immunotherapy Wigs
What is erythema nodosum?
Inflammation of subcutaneous fat
What are the features of erythema nodosum?
Tender
Erythematous
Nodular lesions
Usually over shins but may occur elsewhere too
Give 5 causes of erythema nodosum
1) Infection (TB, strep)
2) Systemic disease (IBD, sarcoidosis, Behcet’s)
3) Malignancy (lymphoma)
4) Pregnancy
5) Drugs (penicillin, COCP, sulphonamides)
Management of erythema nodosum?
Usually self-resolves within 6 weeks
Lesions heal without scarring
Symptomatic treatment, e.g. analgesia
What are the features of pellagra?
4 Ds Diarrhoea Dementia/depression Dermatitis (brown, scaly skin on sun-exposed sites) Death (if not treated)
What causes pellagra?
Deficiency of NICOTINIC ACID (Vit B3)
May occur as result of isoniazid therapy
More common in alcoholics
Management of pellagra?
Vitamin B3 supplementation
What is keratoacanthoma? What is it important to rule out?
Benign epithelial tumour filled with keratin
Looks like volcano/crater
Rule out SSC
Management of keratoacanthoma?
Excision (5% progress to SCC)
However, usually regresses in 3 months (scars)
Itchy, red patches seen in T-zone and in naso-labial folds. Likely diagnosis? What is this due to?
Seborrheic dermatitis Malassezia furfur (over-proliferation of normal skin inhabitant)
Give 2 RFs for seborrheic dermatitis
HIV
Parkinson’s
Which parts of the body does seborrheic dermatitis affect?
Sebum-rich areas: Scalp (may cause dandruff) Periorbital Auricular Nasolabial folds Cheeks
Management of seborrheic dermatitis:
a) On face and body?
b) On scalp?
a) Ketoconazole (topical anti fungal), Topical steroids
b) Head and shoulders shampoo (contains zinc pyrithione), Ketoconazole, Topical steroid (selenium)
What are seborrheic warts? Management?
Benign, epidermal plaques
Vary in colour
May be removed if they are irritating (curettage, cryosurgery, shave biopsy)
What are actinic keratoses?
Premalignant condition associated with chronic sun exposure
What is the spectrum of disease associated with actinic keratosis?
Photodamage > Actinic keratosis > SSC in situ (Bowen’s disease) > Invasive SCC
Give 4 features of actinic keratosis?
Small, crusty, scaly lesions
Vary in colour (pink, red, brown, skin-colour)
Sun-exposed areas (temples of head)
Multiple lesions may be present
Management of actinic keratoses?
Sun avoidance + sunscreen (avoid further risk)
Fluorouracil cream
Cryotherapy
Curettage + cautery
What is the name of the rash you might get due to heat exposure?
Erythema ab igne
What cancer is a patient with erythema ab igne at risk of developing?
SCC
Patient with brown/black velvety hyperpigmentation in body folds (neck, axilla, groin, umbilicus). What is this condition called?
Acanthosis nigricans
What condition is acanthosis nigricans associated with?
Insulin resistance (T2DM) Paraneoplastic (pancreatic, gastric malignancies - suspect if mucous membranes involved)
What would you worry about if you see a patient with acanthosis nigricans that affects the mucous membranes?
Malignancy (e.g. pancreatic, gastric)
How does pyoderma gangrenosum develop?
Starts as small red papule. Develops into deep, red, necrotic ulcer with purple border
May have systemic symptoms (fever, myalgia)
Which part of the body does pyoderma gangrenosum typically affect?
Lower limbs
What are the causes of pyoderma gangrenosum?
50% idiopathic IBD Connective tissue disease - RA, SLE Myeloproliferative disorders Lymphoma, myeloid leukaemia Monoclonal gammopathy Primary bilbos cirrhosis
How is pyoderma gangrenosum treated?
Oral steroids (first line) Immune suppression (ciclosporin, infliximab)
What are the features of lichen sclerosis?
Inflammatory condition affecting vulva
White plaques due to atrophy of epidermis
ITCHY
Management of lichen sclerosis?
Topical steroids
Emollients
Careful follow up due to increased risk of vulval cancer
What are the features of lichen planus?
4 Ps: Purple Polygonal Papules Pruritic
Commonly on palms, soles, genitals
White lace pattern on surface - Wickham’s striae
May see Koebner phenomenon
Oral involvement in 50%
Nail signs: thinning of nail plate, longitudinal ridging
Give 3 causes of lichenoid drug eruptions
Gold
Quinine
Thiazides
How is lichen planus managed?
Topical steroids
Oral disease - benzylamine mouthwash
Oral steroids/immune suppression for extensive disease
What is molluscum contagiosum? What causes it?
Viral disease caused by close personal contact/contaminated surfaces (shared towels, flannels)
What are the features of molluscum contagiosum?
Pink/pearly white papules Central umbilication <5mm diameter Clusters Spares palms and soles
Management of molluscum contagiosum?
Advice: Self-limiting (<18 months), contagious (avoid towel sharing etc)
Treatment: squeeze after bath, cryotherapy, steroids (if itchy), antibiotics if crusty/infected
When would someone with molluscum contagiosum require specialist input?
HIV positive
Eyelid/ocular margin lesions
Anogenital lesions - refer to GUM
What organism causes scabies?
Who does it tend to affect?
Where are the eggs laid?
Sarcopetes scabeii
Children and young adults (uni students in shared houses)
Eggs in stratum corneum
Features of scabies?
ITCH - worse on trunk and between fingers
Linear burrows
Excoriations
Itch persists for about a month after treatment
How is scabies treated?
Permethrin 5% (topical)
Ensure whole household treated on same day. Clothes, bedding, towels washed at high temp.
What is hyperhidrosis and how is it managed?
Excess sweating
Topical aluminium chloride
Electric current - iontophoresis
Botox of axilla
Surgery - endoscopic transthoracic sympathectomy
What is petechiae on tongue/inside gum and telangiectasia on skin suggestive of?
Hereditary haemorrhagic telangiectasia
How is hereditary haemorrhagic telangiectasia inherited?
Autosomal dominant
What are the 4 key diagnostic criteria for HHT?
1) Epistaxis
2) Telangiectasia
3) Visceral lesions
4) FHx
What are the features of pityriasis roses?
Acute self-limiting rash - resolves after 4-12 weeks
Young adults
Associated with HHV-7
‘Herald patch’ - appears on trunk
Followed by erythematous, oval scaly patches on trunk (‘fir tree’)
May have URTI prodrome
What is Steven-Johnson Syndrome?
Systemic reaction to drug
<10% body surface area affected
What is Toxic Epidermal Necrolysis?
Systemic reaction to drug
>35% surface area affected
