Dermatology Flashcards
What is eczema?
Inflammation of the epidermis.
Usually due to a barrier defect, most commonly abnormal Filaggrin. Increased permeability and reduced microbial function.
What are some features of atopic eczema?
Symmetrical
in the inner folds such as front of elbow and behind the knees. cheeks and chin.
High levels of IgE
What are some complications of atopic eczema?
Bacterial infection
Viral infection - viral warts, molluscum, eczema herpiticum
What features describe seborrhoeic dermatitis and what causes it?
Overgrowth of pityrosporum ovale yeast
Chronic scaly inflammation of the face. scalp and eyebrows
What is the pathogenesis of alopecia areata?
T cells surround the hair follicles. CD8, NK cells release pro-inflammatory cytokines and chemokines that reject the hair.
What is erythroderma?
Intense and usually widespread reddening of the skin due to inflammatory skin disease. Associated with exfoliation.
What skin conditions commonly cause erythroderma?
Psoriasis
Drug eruptions
Dermatitis, especially atopic
What are complications of erythroderma?
Secondary skin infections such as cellulitis and impetigo
Red skin can cause high out-put heart failure
Hypothermia
dehydration and electrolyte abnormalities
What are sézary cells?
Cancerous T cells
What is sézary syndrome?
When>20% circulating sezary cells.
Cuatenous T cell lymphoma
What is the pathogenesis of acne?
- Basel keratinocyte proliferation in pilosebaceous follicle (increased sensitivity to androgens)
- Increased sebum production
- Propionibacterium colonisation
- Inflammation
- Comedones block secretions, nodules, cysts, papule.
How would you manage mild acne?
Topical Benzoyl peroxide or topical retinoid (e.g. Isotretinoin)
Or topical antibiotics
If poorly tolerated - Azelic acid
Tx takes 8 weeks to be effective
How would you manage moderate acne?
- Topical antibiotics + Topical benzoyl peroxide (TO REDUCE BACTERIAL RESISTANCE) or Topical retinoid
- Oral antibiotics (Lymecyclin, doxycyline, tetracycline) + Topical benzoyl peroxide
- Topical Benzoyl peroxide + Topical retinoid
How would you manage severe acne?
Refer to a specialist
- Isotretinoin (oral retinoid, conc Vit A) PO 500mcg in 1-2 divided doses daily. 16 week course
- Reduced sebum production and pituitary hormones
- SE - dry skin and lips, myalgia, nose bleeds, teratogenic, depression, deranged LFTs
What is though to cause Rosacea?
High concentration of Cathelicidins, a normal antimicrobial peptide which causes infiltration of neutrophils into the dermis and vasodilation.
Neutrophils then releases nitric acid to further VD
Fluid from leaky vessels - oedema and pro inflammatory cytokines - increases inflammation, thickened, hardened skin
MMPs activate cathelicidins, such as collagnase and elastase
–> Cutaneous inflammation and thick hardened skin
What are some clinical features of Rosacea?
‘Chronic rash involving the centre of the face. Common in those with fair skin, blue eyes, Celtic origin
Red face - persistent redness or telangiectasia
Dry, flaky skin. Flushing of skin
Red papule/pustules on forehead, nose, cheeks and chin
Rhinophyma (nose)
Blepharophyma (eyelids) - conjictivitus, keratitis
Aggrevated by sun exposure and hot and spicy food and drink. and topical steroids, make up etc
Burning and stinging
Urticaria can be characterised by wheals ± angiodema, explain what these mean?
Wheal - Superficial ,skin coloured or pale skin swelling, usually surrounded by erythema, lasts from few min - 24hr Itchy & burning sensation. Few mm - cm, Widespread
Angioedema - Deeper swelling within skin or mucous membranes, can be red or skin coloured and usually resolves within 72hr. Itchy, painful, usually asymptomatic. Localised - Hands, feet, genitals, face
What causes wheal and angiodema in the skin? (Think of chemicals etc)
In wheals, histamine, platelet activating factor and cytokines are released from basophils and mast cells. These activate sensory nerve which cause VD of the BV and so leakage of fluid into the surrounding tissues.
Angioedema is caused by bradykinin release
What is acute and chronic urticaria?
Acute < 6 weeks duration and usually resolves within hours to days
Chronic > 6 weeks and usually episodic or daily wheals
What rash is associated with an Islet cell tumour of the pancreas?
Necrolytic migratory erythema
AKA glucagonoma syndrome
Erythematous, scaly plaques on acral, periorifical and intertriginous areas
What rash is described as ‘Reddened concentric bands of whorled woodgrain pattern’ and what is it linked to?
Erythema gyratums repens
Lung cancer*
But also breast, cervical and GI
Pruitis and peripheral eosinophilia
What is Acanthosis nigricans and its types?
Smooth, velvet like hyperkeratotic plaque on the intertriginous areas.
Type 1 - Adenocarcinoma usually gastric cancer - sudden onset and more extensive
Type 2 - familial, AD, no malignancy, present at brith
Type 3 - Obesity and insulin resistance - most common
What skin change may indicate ovarian cancer?
Erythema annular (red ring like pattern)
What is sweets syndrome?
Also known as acute febrile neutrophilic dermatosis.
Present with a fever and inflamed and blistered skin and mucosal lesions, indicating leukaemia could be present
What skin changes occur in Vit B deficiency? (B6, B12, B3)
B6- Pyridoxine - Dermatitis
B12 - cobalamin - Angular cheilitis
B3 - Niacin - Pellagra - Dermatitis, dementia and diarrhoea
What skin change can occur in Zinc deficiency?
Acrodermatitis enteropathica
Mutation in SLC39A - an intestinal zinc transporter
Pustules, bullae and scaling in acral and perioral regions
Typically cellulitis is caused by strep pyogenes, what antibiotic would you use to treat it?
Ampicillin or Flucloxacillin
Pus forming cellulitis may be caused by s.aureus or MRSA, what antibiotics would you use for these?
S.aureus - Flucloxacillin
MRSA - Vancomycin
What organisms can cause Necrotising fasciitis and what treatment and antibiotics would you use?
Strep e.g. pyogenes, staph e.g. aureus, E.coli, Pseudomonas, clostridium perfringes
Fluid resus
IV Abx - Come Feel My Penis Girl
Clindamycin, flucloxacillin, metronidazole, penicllin, gentamicin,
SURGERY - debridement
What is Necrotising fasciitis?
A rapidly spreading infection of the subcutaneous fascia, over hours. Toxin mediated.
A medical emergency
Initial pain becoming painless, Rapid spread, Systemically unwell. Colour change from red-purple to dusky blue/grey with necrosis. May have skin crepitus
What is Erysipelas?
Superficial form of cellulitis involving the upper dermis and superficial lymphatics.
Involves ears - Milians ear sign. Can cause a Butterfly rash
Streptococcal Pyogenes - Elevated levels of anti-streptococcal antibody titre at 10days
What is impetigo?
Staphylococcal infection of the epidermis
Honey coloured crust, usually perioral
1. Remove crust gently
2. Flucloxacillin
What might you suspect in a patient with recurrent or multiple boils?
PVL producing Staph aureus
PVL toxin destroys WBC
What might a scarlet fever rash look like and why might it occur?
Occurs after a sore throat or impetigo
Group A strep exotoxins or erythrogenic toxins
Tiny pink/red spots covering the whole body.
Strawberry tongue, fever
Occlusion of sweat glands give it a sandpapery touch
What is acne fulminans?
A severe sudden onset ± fever and arthralgia
What treatment is used in severe acne vulgaris?
Oral Isotretinoin (Oral retinoid) Concentrate form of Vitamin A Reduces sebum plugging and bacteria 16 week course SE - nose bleed, dry lips, dry skin, myalgia
What is Psoriasis?
Chronic relapsing, remitting scaly skin disease.
might have PSORS gene on Chromosome 6
Overproduction of skin cells - Red, scaly patched.
T cell mediated AI - produces inflammatory cytokines increasing Keratinocyte proliferation.
What is it called when psoriasis forms at the point of scars and trauma?
Koebner phenomenon
What treatment is available for psoriasis?
- Topical therapy and creams
- Vit D analgoue (Slow keratinocyte proliferation& coal tar)
- Steroids - Reduce redness, inflammation and itching
- Moisturiser to reduce dryness and flaking
- Salicyclic acid (dissolve thick, dead skin) - Phototherapy (UVB)
- Reduced T cell proliferation, encourages Vit D and reduced skin turnover - Systemic therapy
- Immunosuppression: Methotrexate or cyclosporin
- Dimethyl fumerate
- Apremilast
- Acitretin (Oral retinoid) - Biologics
- Adalimumab (anti-TNF) or Ustekinumab (anti-IL12/23)
What pathways may lead to skin cancer?
- Direct effects of UV damage on keratinocytes and neoplastic transformation due to damaged DNA
- Effects of UV on the immune system
What is the most common type of skin cancer and what is the mutation?
Basal cell carcinoma
Slow growing on the face. Due to basal Cell DNA mutation
PTCH gene may predispose
What treatment is available for basal cell carcinoma?
Gold standard - Surgery 3-4mm margin
Curettage and Cautery - scrap and apply heat
Cryotherapy - freeze it
Photodynamic therapy - stimulate bodies immune system
Topical imiquimod / 5-FU - stimulate bodies immune system to target tumour cells
Mohs micrographic surgery - microscope checks margins
What are the subtypes of basal cell carcinoma?
- Nodular: >0.5mm raised, shiny, central ulceration, telangiectasia
- Superficial: flat, broken lightening bolt vessels
- Pigmented: shiny, pigmented, curved edges
- Morphoeic/sclerotic - harder to see
What is the second most common skin cancer?
Squamous cell carcinoma
Arises from keratinocytes
Scaly, yellow, keratin crust
Occurs on areas regularly exposed to sunlight to UV
Risk of mets 10-30% to ears, lips or burns
What skin cancer has premalignant variants and what are they?
Squamous cell
Actinic keratosis - crumbly, yellow, white crust
Bowens disease - red/brown scaly plaque (e.g. on lower legs)
How would you treat Squamous cell carcinoma?
Gold standard - Surgery - 4mm margin
Mutation to what cells can cause melanoma?
Melanocytes
BRAF or NRAS
Spread via lymphatics
How can you stage a melanoma?
Clarks staging and breslows thickness. For 5 year survival Stage 1 = Epidermis 2 = into the papillary dermis 3 = into papillary - reticular junction 4 = into the reticular dermis 5 = into the subcutaneous tissue
What is the most common type of melanoma?
Superficial spreading malignant melanoma
What is the premalignant melanoma called?
Lentigo maligna - pigmented
What systemic therapy can you use in treating melanoma?
Pembrolizumab
What treatment can you use in melanoma?
Surgical excision (<1mm breslow thickness - 1cm margin, >1mm - 2cm margin)
Immunotherapy - Ipilimumab, Nivolumab
Biologica - Debrafanib - BRAF inhibitor
What causes Erythema infectiosum and what is it also known as?
Fifths disease (slapped cheeks)
Human parvovirus B19 via respiratory droplets
Runny nose, fever, headache, pruritic rash
Arthropathy, glove and socks syndrome characterised by popular, purpuric eruptions in the hands and feet.
Acute cessation of RBC production - Aplastic crisis, chronic red cell aplasia, hydrops fetalis, congenital anaemia
What causes hand, foot and mouth disease?
Coxsackie Virus A16
Highly contagious virus in the first few weeks
Oral and distal extremities affected
Fever, headache, oropharyngeal ulcers, sore throat, loss of appetite, rash
What rash characterises measles?
3 days into infection - Koplik spots (on buccal mucosa)
3-5 days = Maculopapular rash
Starts on face and hair line as flat spots
Where does the herpes simplex virus remain latent?
Sensory nerve ganglia
HSV rash- Vesicular and painful
Where does the varicella zoster virus causing shingles remain dormant?
Dorsal root ganglion
Dermatomal distribution
What are some primary skin lesions/ Derm terms?
Macule - flat, not raised, less than 1cm e.g. petechia
Patch - flat, not raised, greater than 1cm e.g. vitiligo
Plaque - flat, elevated, greater than 1cm e.g. psoriasis
Papule- elevated, solid, less than 1cm e.g. angioma, wart
Nodule - elevated, solid, greater than 1cm e.g. epidermal inclusion cyst
Pustule - elevated, pus filled, less than 1cm e.g. acne
Vesicle - elevated, fluid filled, less than 1cm e.g. herpes
Bulla - Elevated, fluid filled, greater than 1 cm e.g. bullous pempighoid
What are secondary skin changes?
As a result of scratching, inflammation or the break down of skin.
Excoriation, crust, scale, ulcer, fissure, lichenification, striae, scar
What is a rash?
A collection of multiple primary skin lesions ± secondary skin changes
4 main types:
Maculopapular, erythematous, vesico-bullous, petechial/purpura
What is the cause of a salmon pink patches affecting the upper back that only appears when pyrexial?
Adult onset stills disease -
Inflammatory arthritis - Rash, Fever and joint pain (particularly wrists)
What is a Herald patch, and what is it seen in?
A single plaque appearing 1-20days before the generalised rash.
Pityriasis Rosea - Viral rash lasting 6-12weeks. Following an URTI. In teens and young adults.
Oval, pink, scaling, edge looks like a collaret
What is Kawasaki disease?
Medium vessel vasculitis!
Acute febrile illness with inflammation of the small and medium blood vessels particular the coronary arteries.
Fever, swelling of hands and feet, lymphadenopathy, oral or ocular signs
How would you describe SJS?
< 10% of the body surface area affected plus widespread erythematous/ purpuric macular rash or flat atypical targets
What scoring tool is used in SJS and TEN?
SCORTEN -
HR, age, presence of malignancy, urea, glucose, bicarbonate, % epidermal detachment
What is the SJS TEN over lap?
10-30% body surface area involvement with widespread purpuric macules or flat atypical targets
TEN >30% epidermal detachement
What are the 5 patterns of psoriatic arthropathy?
Asymmetrical mono- or oligoarthritis Symmetrical poly arthritis Spodyloarthritits Distal interphalangeal arthritis Arthritis Mutalins
What nail signs do you need to look out for in psoriasis?
Pitting, onycholysis, subungual hyperkeratosis, leukonychia, oil drops (yellow orange spots)
What are the patterns of psoriasis?
Plaques (most common)
Erythrodermic
Guttate (often triggered by strep throat, numerous small red patches. in children and adolescents)
Flexural - Anogenital fold and submammary axilla. Pink/red, may have superimposed candida
Palmoplantar - scaling on palms and soles
Pustular - generalised pustular psoriasis is a dermatological emergency
What is a concern about severe allergic urticaria?
May lead to anaphylactic shock - broncospam and collapse
What is Vasculitis?
An AI, inflammatory disease of the blood vessel walls causing destruction (aneurysm or rupture) or stenosis
What are the ANCA associated vasculitis’?
Granulomatosis with polyangitis
Eosinophilic grnaulomatosis with polyangitis
Microscopic polyangitis
What are some clinical features seen in Giant cell arteritis?
GCA - Rare < 50, peak 70-79
Females
Temporal headache with tenderness - noticed scalp tenderness when brushing hair
Jaw claudication - pain on chewing, relieved when stop
Polymyalgia Rheumatica
Visual symptoms - complication: Acute ischaemic optic neuritis - SUDDEN PAINLESS IRREVERSIBLE VISUAL LOSS - interrupted flow in the posterior ciliary artery - isachamia of the optic nerve
Constitutional upset - Weight loss, fever, myalgia, malaise
What investigations can you do for Giant cell arteritis?
Look for Temporal artery asymmetry, thickening, loss of pulsility?
GOLD STANDARD - Temporal artery biopsy - Remove a long segment as the internal elastic lamina has interrupted* inflammatory infiltrate such as multinuclear giant cells. Segmental*
Temporal artery USS - Hypoechoic halo sign
How would you manage giant cell arteritis?
If suspected IMMEDIATELY start steroids to prevent progression to visual loss!!
60mg Prednisolone for 1 month then try to taper to 15mg by 12 weeks, then try stop by 1-1.5y
If relapse - Methotrexate, tocrilizumab (anti-IL-6), mycophenolate mofetil
What is a small vessel vasculitis that can be seen in children and is ANCA negative?
Henoch- Schönlein Purpura - IgA vasculitis
Triggered by an URTI. Self-limiting 4-16weeks
Seen in children, but mean age 43, M>F
IgA depositions in BV
Palpable purpura on bum and legs
Joint pain - arthralgia
Abdomina pain, Diarrhoea
Renal involvement - IgA nephropathy
What is characteristic about granulomatosis with polyangitis or Wegners granulomatosis?
TRIAD: Involved Upper and lower respiratory tract and kidneys. -
Granulomatous necrotising inflammatory lesions of the URT (e.g. rhinitis, chronic sinusitis, saddle nose deformity) and LRT (alveolar haemorrhage)
Pauci-immune glomerulonephritis
ANCA positive - PR3 (c-ANCA)
Constitutional Sx.
What does p-ANCA with strong MPO suggest?
microscopic polyangitis or eosinophilic granulomatosis with polyangitia
c-ANCA with strong PR3 - GPA
How would you manage GPA?
In severe disease
Induction (3-6 months)
Prednisolone + cyclophosphamide
Maintenance (2+ years) - Methotrexate, azathioprine or mychophenolate mofetil
Non-severe - induction (3-6m) Methotrexate + Pred
maintenance - methotrexate
What is cellulitis?
A bacterial infection of the lower dermis and the subcutaneous tissue.
Strep progenies, Staph aureus
Risks- Diabetes, CKD, CLD, alcoholism, obesity, HIV, tattoos, bites, venous insufficiency, burns
Red, painful, swollen skin with systemic Sx (bacteraemia, first presentation of cellulitis may be unwell - rigors, fever, chills, before becoming a localised skin lesion)
What organism might cause cellulitis due to entry through a puncture wound?
Pseudomonas aeruginosa
What are some complications of severe or rapidly progressive cellulitis?
Necrotising fasciitis Gas gangrene Severe sepsis Infection - pneumonia, osteomyelitis, meningitis Endocarditis
What clinical features are seen in cellulitis?
Peu d’orange, warmth, blistering, abscess, purpura, erosion and ulceration, abscess formation
What is an abscess?
A collection of pus surrounded by a pyogenic membrane
Red, hot, tender swelling. Its generally unwell
What is a leg ulcer?
A full thickness loss of the leg below the knee or foot due to any cause that usually takes > 2 weeks to heal.
Arterial, venous, neuropathic, pressure
What are the risk factors for leg ulcers?
Chronic venous insufficiency, chronic arterial insufficiency, Diabetes, HTN
CVI - improper functioning of valves, reflux, poor pumping action of calves - pooling of blood. Inc venous pressure - fibrin deposits around cap, barrier to flow of O2 and nutrients - ulceration
CAI - poor circulation to lower foot and leg due to Atherosclerosis - narrowing, fail to deliver blood and nutrients to tissue - death of tissue - ulcer
Describe venous and arterial ulcers.
Venous - Between lower calf and medial malleolus. Associated with varicose veins, lipodermatosclerosis, phlebitis, DVT. Shallow and flat, mod-heavy exudate, slough and granulation tissue. Haemosiderin stained, thickened skin. Painless. Relieved when resting and elevated. Compression banding helps.
Arterial - Feet, heels, toes. Atherosclerosis. Punched out deep with irregular borders, some necrotic tissue. Little exudate. Reduced or absent pulses, reduced CRT, shiny, pale, cool, hairless skin. Intermittent claudication. Painful, esp at night when legs at rest and elevated. Relieved with feet on floor when gravity allows better blood flow. Revascularise, anti-platelets, Tx risk factors
What is a pressure ulcer?
Caused by uninterrupted pressure on the skin leading to ulcers and extensive, painful SC destruction, e.g. on heel, sacrum, greater trochanter and elbows
Implicating factors:
- Shearing forces from sliding down the bed
- Moisture from incontinence
- Friction when dragged across a bed sheet
What is a complication of a pressure ulcer?
Osteomyelitis
What are the types of burns?
Superficial/1st - Epidermis only - dry/red, painful, blanched on pressure. healing <7days
Partial thickness/2nd - Epidermis and dermis - painful, blisters, heals <21d, Abx/surgery/graft
Full thickness/3rd - to subcutaneous tissue - non-blanching, painless - surgery
4th degree - to muscle/bone/fascia - surgery
What is bullous pemphigoid?
Chronic blistering disorder. in Elderly
IgG to hemidesmosomes, Subepidermial bullae on a erythematous or utricarical base
Associated with stroke or dementia
What is bullous pemphigus?
In younger people - Due to ACEi, NSAIDs
IgG to desmosomes so keratinocytes separate
