Dermatology Flashcards by Hend R

What is BCC?

Basal cell carcinoma::: slow growing :::: locally invasive :::: malignant :::: irregular growth :::: sun exposure :::: white ppl

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What is the classic description of BCC?

small, translucent, pearly, raised areas with telangiectasia
rodent ulcer - indurated edge and ulcerate centre

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What are the different types of BCC?

Nodular - solitary, shiny red with large telangiectasia

Superficial - erythematous well-demarcated scaly plaques

Morphoeic - thickened yellow plaques, poorly defined borders

Pigmented - brown, blue or greyish

Basosquamous - mixed BCC and SCC

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What is SCC? How does it present?

Squamous cell carcinoma ::: malignant tumour ::: can metastasise ::: UV light exposure

Presentation:
- usually indurated nodular keratinising or crusting tumour, may ulcerate
- non-healing growth or ulcer
- very variable clinical appearance

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What is the management of SCC?

2ww referral

Surgical excision with 4mm margin is lesion <20mm in diameter, 6mm if >20mm in diameter

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What are some indications of poor prognosis in SCC?

poorly differentiated tumour
> 20mm in diameter
> 4mm deep
immunosuppression

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What bacteria causes inflammation in acne?

Propionibacterium acnes

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How does acne present?

open or closed comedones (blackheads and whiteheads)
papules, pustules, nodules, cysts

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What is the pathophysiology of acne?

increased sebum production
follicular hyperkeratinisation
colonisation with P. acnes
inflammation

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What is the management of mild to moderate acne vulgaris?

a 12-week course of topical combination therapy should be tried first-line:
- a fixed combination of topical adapalene with topical benzoyl peroxide
- a fixed combination of topical tretinoin with topical clindamycin
- a fixed combination of topical benzoyl peroxide with topical clindamycin

topical benzoyl peroxide may be used as monotherapy if these options are contraindicated or the person wishes to avoid using a topical retinoid or an antibiotic

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What is the management of moderate to severe acne?

a 12-week course of one of the following options:
- a fixed combination of topical adapalene with topical benzoyl peroxide (same as mild)
- a fixed combination of topical tretinoin with topical clindamycin (same as mild)
- a fixed combination of topical adapalene with topical benzoyl peroxide + either oral lymecycline or oral doxycycline
- a topical azelaic acid + either oral lymecycline or oral doxycycline

avoid tetracyclines in pregnant and breastfeeding women

COCP

oral isotretinoin under specialist supervision

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What is the management of eczema?

topical emollients
soap substitutes
avoid triggers

topical steroids :
- Mild: Hydrocortisone 0.5%, 1% and 2.5%
- Moderate: Eumovate (clobetasone butyrate 0.05%)
- Potent: Betnovate (betamethasone 0.1%)
- Very potent: Dermovate (clobetasol propionate 0.05%)

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“symmetrical, brown, velvety plaques that are often found on the neck, axilla and groin”

Acanthosis nigricans

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What are some causes of acanthosis nigricans?

things to do with insulin resistance e.g. T2DM, obesity, PCOS, acromegaly, Cushing’s, hypothyroid, Prader-Willi
GI cancer
familial
drugs (COCP, nicotinic acid)

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“multiple small crusty/scaly lesions, pink/red/brown/skin colour, sun-exposed areas”

actinic keratoses

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What is the risk of actinic keratosis?

What are management options for it?

it’s premalignant

Mx:
- avoid sun exposure
- fluorouracil cream (2-3wks) - causes redness and inflammation
- topical diclofenac, topical imiquimod
- cryotherapy
- curettage and cautery

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What are the types of alopecia?

Scarring (trauma, burns, other skin conditions - destruction of hair follicle)
Non-scarring (male-pattern baldness, drugs, iron/zinc deficiency, telogen effluvium/stress)

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What drugs can cause alopecia?

cytotoxic drugs, carbimazole, heparin, oral contraceptive pill, colchicine

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What are treatments for alopecia areata?

hair usually regrows in 50% of pts within 1 yr
- topical or intralesional corticosteroids
- topical minoxidil
- phototherapy
- dithranol
- contact immunotherapy
- wigs

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“elderly patient, itchy, tense blisters around flexures heal without scarring, no mucosal involvement”

Bullous pemphigoid

Skin biopsy shows: immunofluorescence shows IgG and C3 at the dermoepidermal junction

Mx: referral to derm for biopsy, PO corticosteroids

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How can you assess extent of burns?

Wallace’s Rule of Nines:
head + neck = 9%, each arm = 9%, each anterior part of leg = 9%, each posterior part of leg = 9%, anterior chest = 9%, posterior chest = 9%, anterior abdomen = 9%, posterior abdomen = 9%

Lund and Browder chart is most accurate

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How can you assess the depth of a burn?
1) 1st deg - superficial epidermal
2) 2nd deg - partial thickness, superficial dermal
3) 2nd deg - partial thickness, deep dermal
4) 3rd deg - full thickness

1) Red and painful, dry, no blisters
2) Pale pink, painful, blistered. Slow capillary refill
3) Typically white but may have patches of non-blanching erythema. Reduced sensation, painful to deep pressure
4) White (‘waxy’)/brown (‘leathery’)/black in colour, no blisters, no pain

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When are IV fluids needed in burns?
How is fluid requirement calculated?

Children with burns >10%
Adults with burns >15%

Parkland formula: volume of fluid = total body surface area of the burn % x weight (Kg) x4.
Half of the fluid is administered in the first 8 hours.

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When are escharotomies indicated in burns?

circumferential full thickness burns to torso or limbs

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"painful nodule on the ear, usually in old men"

Chondrodermatitis nodularis helicis benign condition

"erythematous plaques covered with a silvery-white scale, typically on the extensor surfaces"

Chronic plaque psoriasis

"autoimmune blistering skin disorder associated with coeliac disease, itchy, vesicular skin lesions on the extensor surfaces"

Dermatitis herpetiformis skin biopsy: direct immunofluorescence shows deposition of IgA in a granular pattern in the upper dermis Mx: - gluten free diet - dapsone

"solitary firm papule or nodule, typically on a limb, typically around 5-10mm in size, overlying skin dimples on pinching the lesion"

Dermatofibroma benign fibrous lesion

"child with atopic eczema, rapidly progressive painful rash, monomorphic punched-out erosions (circular, depressed, ulcerated lesions) usually 1-3 mm in diameter"

Eczema herpeticum life-threatening needs admission and IV aciclovir

"reticulated, erythematous patches with hyperpigmentation and telangiectasia, exposure to infrared radiation"

Erythema ab igne risk of SCC

"target lesions, back of hands and feet spreads to torso , mild pruritis"

Erythema multiforme Causes - viruses: herpes simplex virus (the most common cause), Orf* - idiopathic - bacteria: Mycoplasma, Streptococcus - drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine - connective tissue disease e.g. Systemic lupus erythematosus - sarcoidosis - malignancy

"tender, erythematous, nodular lesions, typically over shins"

Erythema nodosum Causes - infection: streptococci, tuberculosis, brucellosis - systemic disease: sarcoidosis, IBD, Behcet's - malignancy/lymphoma - drugs: penicillins, sulphonamides, COCP - pregnancy

"acute onset, tear drop papules on the trunk and limbs, 2-4wks after strep infection"

Guttate psoriasis Mx: resolve spontaneously - or same Tx as psoriasis, UVB phototherapy

"2-3 of: epistaxis, telangectasia, visceral lesions (e.g. AVMs), family history"

hereditary haemorrhagic telangiectasia

What are some treatment options for hyperhidrosis?

Management options include - topical aluminium chloride preparations are first-line. Main side effect is skin irritation - iontophoresis: particularly useful for patients with palmar, plantar and axillary hyperhidrosis - botulinum toxin: currently licensed for axillary symptoms - surgery: e.g. Endoscopic transthoracic sympathectomy. Patients should be made aware of the risk of compensatory sweating

"'golden', crusted skin lesions typically found around the mouth"

Impetigo (staph aureus, strep pyogenes)

What is the management for limited impetigo?

- hydrogen peroxide 1% cream for 'people who are not systemically unwell or at a high risk of complications' - topical Abx cream: fusidic acid, mupirocin

What is the management of extensive impetigo?

oral flucloxacillin, oral erythromycin if penicillin-allergic

What are the rules around school exclusion for impetigo?

children should be excluded from school until the lesions are crusted and healed or 48 hours after commencing antibiotic treatment

How can keloid scars be treated?

intra-lesional steroids e.g. triamcinolone

"said to look like a volcano or crater, initially a smooth dome-shaped papule, rapidly grows to become a crater centrally-filled with keratin"

Keratoacanthoma benign epithelial tumour, urgent surgical excision if difficult to differentiate from SCC

"purple, polygonal, pruritic. white-lines (Wickham's striae), Koebner phenomenon"

Lichen planus Lichenoid drug eruptions - causes: - gold, quinine, thiazides Mx: - topical steroids - benxydamine mouthwash for oral lichen planus

"white patches, itchy, usually on genitalia"

Lichen sclerosus Mx: top steroids and emollients inc risk of vulval Ca

What are the main subtypes of malignant melanoma?

- Superficial spreading - Nodular (most aggressive) - Lentigo maligna - Acral lentiginous

What are the main diagnostic features of malignant melanoma?

The main diagnostic features (major criteria): Change in size Change in shape Change in colour

"pinkish or pearly white papules with a central umbilication, which are up to 5 mm in diameter, close contact transmission, mainly in children"

molluscum contagiosum self-limiting

"itchy, red patches which are typically confused with eczema or psoriasis initially, lesions tend to be of different colours in contrast to eczema/psoriasis where there is greater homogenicity"

Mycosis fungoides - rare form of T-cell lymphoma

"dermatitis, diarrhoea, dementia"

Pellagra

"mucosal ulceration, skin blistering (flaccid, easily ruptured)"

Pemphigus vulgaris steroids first line

"herald patch, erythematous, oval, scaly patches, a 'fir-tree' appearance"

Pityriasis rosea self-limiting

"type of eczema which affects both the hands and feet, precipitated by humidity and high temp"

Pompholyx Mx: cool compress, emollients, topical steroids

What is the 1st line treatment for chronic plaque psoriasis?

a potent corticosteroid applied once daily plus vitamin D analogue applied once daily

"acute onset small pustule/red bump/blood blister on lower limb, develops into painful ulcer, with purple edge, may be deep/necrotic, associated with fever"

Pyoderma gangrenosum - PO steroids 1st line

"small red/brown spot, rapidly progress within days to weeks forming raised, red/brown lesions which are often spherical in shape, may bleed profusely or ulcerate"

Pyogenic granuloma (misnomer) benign

What are some adverse effects of retinoids (e.g. isotretinoin)?

- teratogenecity (use COCP) - dry skin/eye/mouth - low mood - raised triglycerides - hair thinning - epistaxis - ICH - photosensitivity

What is the management of rosacea?

- sunscreen - brimonidine - topical ivermectin for papules/pustules - topical vermectin and oral docycyline for mod-severe papules/pustules

What is the management of scabies?

permethrin 5% is first-line malathion 0.5% is second-line

What are some causes of SJS?

- penicillin - sulphonamides - lamotrigine, carbamazepine, phenytoin - allopurinol - NSAIDs - oral contraceptive pill

"maculopapular with target lesions, Nikolsky sign is positive in erythematous areas - blisters and erosions appear when the skin is rubbed gently, mucosal involvement, fever, arthralgia"

Steven-Johnson Syndrome

"scalded appearance over an extensive area, systemically unwell, positive Nikolsky's sign: the epidermis separates with mild lateral pressure"

Toxic epidermal necrolysis life-threatening Drugs known to induce TEN: - phenytoin - sulphonamides - allopurinol - penicillins - carbamazepine - NSAID Mx: - supportive care - IV Ig

"ulceration above medial malleolus, ABPI 0.9-1.2"

Venous ulceration Mx: compression bandaging PO pentoxifylline