Dermatology Flashcards
(33 cards)
What are the stages of wound healing
Haemostasis: vasoconstriction and platelet aggregation, clot formation
Inflammation: vasodilation, migration of neutrophils + macrophages, phagocytosis of debris and bacteria
Proliferation: granulation tissue formation (fibroblasts) and angiogenesis, re-epithelialisation (epidermal cell proliferation + migration)
Remodelling: collagen fibre reorganisation, scar maturation
Urticaria patho, Px, Mx
Local increase in permeability of capillaries + small venules, histamine and inflammatory mediators, induced by immunological or non mechanisms
Px: itchy wheals (superficial swelling, epidermis raised), angioedema (swelling of tongue + lips)
Mx: antihistamines;+ corticosteroids
Anaphylaxis patho, Px, Mx
Anaphylaxis: primarily IgE mediated hypersensitivity, sensitisation during initial exposure to allergen (antigen presenting cells, T cells, T helper 2 (cytokines), IgE antibodies, mast + basophils), effector phase (mast + basophils)
Anaphylaxis: bronchospasm, facial + laryngeal oedema, hypotension. Swelling of throat / tongue - hoarse + stridor, wheeze, dyspnoea, hypotension, tachycardia. Generalised pruritus, widespread rash
anaphylaxis: IM adrenaline (adults 500 micrograms / 0.5ml 1 in 1000) every 5 minutes; more than 2: IV fluids, senior help +/- IV
Following anaphylaxis: chlorphenamine, serum tryptase can be used to determine, new diagnoses to specialist allergy clinic. Can discharge after 2h if good response, 6h-12 depending
Erythema nodosum patho, Px
IV hypersensitivity response to: Group A beta-haemolytic strep, primary TB, pregnancy, malignancy, sarcoidosis, IBD, chlamydia, leprosy
Px: discrete tender nodules (may become confluent), appear for 1-2w and leave bruise like discolouration when resolve, shin most common site
Erythema mulitforme / SJS / toxic epidermal necrolysis description, Px, Mx, causes
Erythema multiforme: often unknown cause, acute self limiting inflammatory condition, herpes simplex virus main precipitating factor (other infections, drugs), mucosal involvement maximum one surface
Target lesions (central necrosis surrounded by erythema), hands / feet / torso. Major = mucosal involvement, and systemic sx
SJS: mucocutaneous necrosis with at least 2 mucosal sites, skin involvement ranges, drugs or infections + drugs. Extensive necrosis (seen on histopathology with few immune cells)
Px: painful burning eruption, loss of epidermis, prodromal illness (URTI), nikolsky sign positive - soft rubbing of skin results in removal
Hospital admission, supportive care with fluids
TEN: extensive skin and mucosal necrosis accompanied by systemic toxicity, usually drug induced. Histopathology has full thickness with subepithelial detachment
Nikolsky sign positive, fever + tachycardia, leads to sepsis and hypovolaemic shock
IV abx and IV IG
Common drugs: antibiotics (sulfonamides, penicillins, cephalosporins), antiepileptics (phenytoin, carbamazepine, lamotrigine), allopurinol, nevirapine (antiviral), piroxicam (NSAID)
Erythroderma description, Px, Mx
Exfoliative dermatitis involving at least 90% skin surface; previous skin disease, lymphoma, drugs, idiopathic
Px: inflamed, oedematous, scaly, systemically unwell (lymphadenopathy, malaise
Mx: treat cause, emollients, wet wraps, topical steroids
Eczema herpeticum Px, Mx, complications
Px: rapidly worsening painful eczema, vesicular (blistering) rash, punched-out uniform erosions 1-3mm, starts in affected areas then spreads to normal skin 1-2w, systemically unwell (fever, malaise)
Mx: aciclovir 5* 10-14d, antibiotics for secondary infection if required. Referral to dermatologist, same day ophthalmologist if eye involvement
Complications: herpes hepatitis, encephalitis, DIC, recurrent herpes
Necrotising fasciitis description, Px, Ix, Mx
Severe and rapidly progressive soft tissue infection causing necrosis of subcutaneous tissues and fascia (sometimes muscle). Most commonly in diabetes, following trauma / surgery. Can affect limbs, perineum, genitals (Fournier’s gangrene) or abdominal wall
Px: swelling, severe pain, erythema / blistering / necrotic, induration. Rapid progression, blistering and bullae, failure to response to abx, grey skin, skin crepitus. Systemic: diarrhoea + vomiting, tachycardia, fever, hypotension, tachypnoea, sepsis
Ix: NF score bloods (Hb, WCC, Na, creatinine, glucose, CRP); Xray may show subcutaneous gas, CT / MRI, incisional biopsy
Mx: urgent surgical debridement - fasciotomy, IV abx depending on organism (flucloxacillin, benzylpenicillin)
Eysipelas vs cellulitis, Px, Ix, Mx
Erysipelas is acute superficial form of cellulitis involving dermis and upper subcutaneous tissue. Cellulitis is infection of deep subcutaneous. Usually strep pyogenes or staph aureus
Px: usually unilateral and leg, swelling, erythema, warmth pain. Systemically fever, malaise, rigours. Erysipelas has well defined raised red border
Bilateral or slowly progressive less likely, rapidly progressive blistering consider necrotising fasciitis
Ix: bloods (FBC, U+Es, CRP / ESR), wound swab, blood cultures in IC or atypical
Mx: analgesia, oral flucloxacillin (clarithromycin); severe: co-amoxiclav / clindamycin / cefuroxime. Elevate area, sterile dressings, mark areas to check progression
Referral: Eron class III or IV: significant systemic upset, unstable comorbidities, is immunocompromised, significant lymphoedema, facial / periorbital cellulitis
Staph scladed skin syndrome Px, Mx
Px: develops quickly, face / neck / axillae / groin, scalded appearance followed by large flaccid bulla, perioral crusting, painful lesions
Mx: flucloxacillin, erythromycin, analgesia
What are the 3 main groups of fungal infections, Ix, Mx
3 main groups: dermatophytes (tinea / ringworm), yeasts (candidiasis, malassezia), moulds (aspergillus)
Ix: clinical, skin scrapings / nail or hair clippings, skin swabs (yeast)
Mx: topical terbinafine, oral itraconazole (fluconazole) in systemic or nail, correct predisposing factors
Px of tinea corporis / pedis / manuum / capitis / unguium / incognito / vesicolour, candidiasis
Tinea corporis: trunk + libs, itchy, circular / annular lesions, clearly defined, scaly edge
Tinea pedis (athlete’s foot): moist scaling + fissuring in toewebs, spreads to sole + dorsum
Tinea manuum: hands, scaling + dryness, palmar creases
Tinea capitis (scalp ringworm): patches of broken hair, scaling and inflammation
Tinea unguium: nail, yellow discolouration, thickened and crumbly nail
Tinea incognito: inappropriate treatment with steroid, ill defined and less scaly
Pityriasis / tinea vesicolour (malassezia furfur): scaly brown patches on upper trunk, fail to tan in sun, asymptomatic
Candidiasis: white plaques on mucosal surface, erythema with satellite lesions in flexures
Scabies patho, Px, Mx
Mite sarcoptes scabiei colonises skin and lays eggs in epidermis, T4 hypersensitivity to eggs (up to a month after exposure - skin to skin), inflammatory cytokine release
Px: pruritus, worse at night, linear burrows (thread like grey lines with small vesicle and black dot at end), erythematous papules on side of fingers / web spaces / under nails
Mx: whole household, whole body permethrin (8-12h) or malathion (24h); severe: topical insecticide and oral ivermectin
Squamous cell carcinoma Patho, RF, Px, Mx
Locally invasive malignant tumour of epidermal keratinocytes or appendages, potential to metastasise
RF: UV exposure, premalignant conditions (actinic keratoses), chronic inflammation, IC
Px: keratotic, scaly, crusty, ill defined nodule which may ulcerate
Mx: surgical excision (or Mohs micrographic), radiotherapy for non resectable
Malignant melanoma patho, Px, Ix, prognosis indicator, Mx
Invasive malignant tumour of epidermal melanocytes. Radial growth along epidermis + superficial dermis, vertical growth into deep dermis
Px: starts as unusual freckle / mole, becomes abnormal (ABCDE): asymmetry, borders irregular, colour not uniform, diameter >6mm, evolution of lesion. Bleeding, itching
(Superficial spreading (70%): limbs and torso of young people. Nodular: most aggressive, bleeds. Lentigo maligna: slowly progressive in situ. Acral lentiginous: rare form with pigmentation under nails / palms / soles of black and asian people)
IX: biopsy and sentinel lymph node mapping
Prognosis - depth of tumour (Breslow thickness) most important factor: <1mm 95% 5y survival, >4mm 50%
Mx: surgical removal (second wide local excision often needed) +/- sentinel lymph node biopsy, chemo / radio / targeted therapy
Atopic eczema patho, Px, Mx
Primary genetic defect in skin barrier function (filaggrin protein), mediated by increased Th2 cells, promoted pathogen specific IgE (TI hypersensitivity) - eosinophils and mast cells. Irritants enter easier and cause inflammatory response
Exacerbating factors: infections, allergens (chemicals, food, dust, pet fur), sweating, heat, occupation, stress
Px: acute: erythematous fissuring, itchy papules + vesicles, weepy; chronic: dry, clay patches; distribution: babies - face and torso, older - flexor surfaces + face creases (sweat concentration)
Chronic scratching leads to lichenification, hypopigmentation, nail pitting / ridging
Mx: avoid exacerbating agents, frequent emollients (hydromol, diprobase) +/- bandages. Topical steroids for active areas (10:1 with emollient, 1 fingertip for double area of hand); hydrocortisone (weakest), eumovate, betnovate (potent), fucidin H (hydrocortisone + fusidic acid for infections)
Tacrolimus (calcineurin inhibitor), for maintenance in severe, phototherapy and immunosuppression (azathioprine) in severe non responsive
Px of eczema secondary infections, discoid, sebhorrhoeic, contact, dyshidrotic
Secondary infections: bacterial (crusted, weepy) - flucloxacillin, eczema herpeticum (extensive crusted papules, blisters, swollen lymph glands + fever, untreated can lead to eyes / brain / lung) - aciclovir. Molluscum - pearly papules with central umbilication
Discoid eczema: round erythematous patches, arms and legs, starts as red spots that merge together. Mild steroids
Seborrheic: chronic in sebum rich areas (scalp and face), abnormal response to malassezia furfur leading to inflammation. Yellow scale on scalp (cradle cap), regular shampoo, ketoconazole in severe. Adults will be pink thin scaly plaques in folds, mild steroids in flare, ketoconazole
Contact: redness, dryness, swelling, fissuring, only areas exposed (usually hands). Avoid contact, less soap, better gloves, emollients, steroids
Dyshidrotic: blisters on fingers / palms / soles, unknown cause but related to seasonal allergies. Intense itching, burning, large painful blisters which flake off, lasts up to 3w. Emollients + steroids
Psoriasis patho and types
Chronic inflammatory condition due to hyperproliferation of keratinocytes and T cell activity. Genetic predisposition and environmental triggers (stress, trauma, infection, medications)
Plaque: most common (90%), well defined, red, scaly patches, extensor surfaces + head
Flexural (inverse): smooth, well defined plaques, folds + genitals
Guttate: self resolving teardrop lesions, following strep infection
Generalised pustular: flares of pustules superimposed of red painful skin
Psoriasis Px, Ix, Mx
Px: red salmon rash, plaque formation, nail changes (pitting, onycholysis), auspitz sign (removal of scales leads to pinpoint bleeding), Koebner phenomenon (new plaques at sites of skin injury), psoriatic arthritis in roughly 30%
Ix: mostly clinical, skin biopsy, bloods, rheumatology screening. Psoriasis area severity index (PASI) - extent of surfaces, intensity of redness, thickness and scaling
Mx: avoid triggers, emollients; FL: topical steroids + calcitriol (Vit D) for 4w; add phototherapy; methotrexate, etanercept, apremilast for refractory disease
Acne vulgaris Px, Mx, referral
Px: early: open (blackheads) and closed (whiteheads) comedones; inflammatory: papules, pustules; severe: nodules, cysts. Face / chest / back as highest concentration of sebaceous glands
Leads to ice-pick and hypertrophic scars
Drug induced: monomorphic - steroids cause pustules
Mx (12w): mild: adapalene / tretinoin (retinoid) + benzoyl peroxide; inflammatory: add topical clindamycin or azelaic acid; moderate: tretinoin / adapalene and oral lymecycline or doxycycline; severe: oral isotretinoin +/- oral / injection steroids
Hormonal in women: COCP, spironolactone
Referral: any not responded to 2 courses, not responded to oral abx, scarring / persistent pigmentary changes, persistent psychological distress. Only dermatologists can prescribe oral retinoids
Roascea Px, Ix, Mx
Px: nose / cheeks / forehead, flushing, telangiectasia, erythema with papules + pustules, rhinophyma (large, red, bumpy), sunlight exacerbates
Ix: clinical diagnosis, exclusion of acne / seborrhoeic dermatitis / lupus
Mx: high factor suncream; erythema / flushing - brimonidine (alpha agonist); papules / pustules: ivermectin, severe ivermectin + oral doxycycline
Referral for persistent or rhinophyma
Bullous pemphigoid Px, Mx
Autoantibodies against antigens between epidermis and dermis causing subepidermal split in skin, typically elderly
Px: tense, fluid filled blisters, erythematous base, itchy, trunk and limbs (sometimes mucosa)
Mx: wound dressings, monitor infection, topical steroids; systemic: oral steroids, tetracycline + nicotinamide
Pemphigus vulgaris Px, Mx
Autoantibodies against antigens within epidermis - intraepidermal split in skin, typically middle aged
Px: flaccid, easily ruptured blisters forming erosions and crusts, painful, mucosal most common
Mx: wound dressing, monitor infection, high dose oral steroids, methotrexate / azathioprine
Vitiligo Px, Mx
AI condition resulting in loss of melanocytes. Unknown cause, associated with: T1DM, addison’s, AI thyroid, pernicious anaemia, alopecia
Px: any age, well demarcated patches of depigmented skin (often symmetrical), face / hands / feet / body folds / genitalia, Koebner phenomenon
Mx: minimise injury, suncream +/- makeup for affected areas, potent topical steroids (mometasone) can reverse if applied early enough, tacrolimus and phototherapy also used. Severe: methotrexate, oral dexamethasone, surgery
