Dermatology Flashcards

Question

venous ulceration - useful Ix? normal and abn values? - where are they ususally? - mx?

Answer 1

Ix most useful in determining mx: ABPI Mx: compression bandaging, usually four layer NOTES typically seen above the medial malleolus Investigations • ABPI: important in non-healing ulcers to assess for poor arterial flow which could impair healing ○ 'normal': 0.9 - 1.2 ○ <0.9: arterial disease ○ >1.3 may also indicate arterial disease, in the form of false-negative results secondary to arterial calcification (e.g. In diabetics)

Answer 2

- Features: flushing, abdo pain + urticaria pigmentosa ○ UP: produces a wheal on rubbing (Darier's sign) - Dx: urinary histamine - Cause: neoplastic proliferation of mast cells - Ix: high serum tryptase, high urinary histamine, monocytosis on blood film

Answer 3

- Cause: Malassezia furfur - Tx: ketoconazole shampoo (2nd line oral itraconazole + skin scraping to confirm dx) - Multiple hypopigmented/pink/brown patches on trunk w scale and itch. - RF: cushings, immunosuppression, malnutrition

Answer 4

``` Mx: watchful waiting for spontaneous remission Other treatment options include: • topical or intralesional corticosteroids • topical minoxidil • phototherapy • dithranol • contact immunotherapy • wigs ```

Answer 5

- Itchy rash over face/scalp + otitis externa, blepharitis - Cause: malassezia furfur - Ass HIV and PD - Scalp: over the counter stuff, then ketoconazole. Face/body: topical ketoconazole

Answer 6

LS: itchy white spots typically seen on the vulva of elderly women NOTES Features: can occur on genitals, thighs, anal region. In M: glans penis usually = balanitis xerotica obliterans Dx: usually clinical, but can do biopsy if atypical fts Mx: topical steroids and emollients Increased risk of vulval cancer

Answer 7

HSV 1 or 2 (uncommonly coxsackievirus) Admit children for IV aciclovir (as potentially fatal) NOTES PC: rapidly progressing painful rash - In kid with atopic eczema monomorphic punched-out erosions (circular, depressed, ulcerated lesions) usually 1–3 mm in diameter

Answer 8

Management • Mild: topical metronidazole (i.e. Limited number of papules and pustules, no plaques) • Mainly flushing (limiting telangiectasia): topical brimonidine gel • more severe: systemic antibiotics e.g. Oxytetracycline Also • high-factor sunscreen OD • camouflage creams may help conceal redness • laser therapy if prominent telangiectasia • patients with a rhinophyma: refer to derm

Answer 9

PEMPHIGUS VULGARIS KEY BITS - Flaccid vesicles + mucosal involvement - Abs against desmoglein 3 NOTES - 30-50y old - more common in the Ashkenazi Jewish population. Features - mucosal ulceration: common. Oral involvement in 50-70% - skin blistering - flaccid, easily ruptured vesicles and bullae. ○ painful but not itchy ○ Can be months after mucosal symptoms. ○ Nikolsky's describes the spread of bullae following application of horizontal, tangential pressure to the skin - Biopsy: acantholysis Mx: 1st line steroids PEMPHIGOID - Subepidermal blistering - Due to Abs against hemidesmosomal proteins BP180 and BP230. Elderly pt with - itchy, tense blisters typically around flexures - usually heal without scarring - no mucosal involvement Biopsy: immunofluorescence shows IgG and C3 at the dermoepidermal junction Mx 1. Refer for biopsy and confirmation 2. Oral steroids

Answer 10

Koebner phenomenon (new skin lesions at the site of trauma)

Answer 11

• gold • quinine Thiazides

Answer 12

- Melasma = big brown patch on face, benign. No tx - Atopic eruption of pregnancy = itchy red eczematous rash. No tx - Polymorphic eruption of pregnancy = last trimester. Itchy lesions in abdominal striae. - Pemphigoid gastationis: itchy blistering lesions. Oral steroids.

Answer 13

Niacin/nicotinic acid (b3 def): dermatitis, diarrhoea and dementia Can be due to isoniazid More common in alcoholics.

Answer 14

``` Overview = inflam of subcutaneous fat • Painful red nodular lesions • Usually on shins but can be elsewhere EG forearms • Heal by themselves in 6 weeks • Heal without scarring ``` Causes • Infection: strep, TB • Pregnancy • Systemic disease: sarcoid, IBD, behcet's • Drugs: COCP, sulphonamides, penicillin • Malignancy/lymphoma

Answer 15

- Irritant: common, non-allergic reaction, due to weak acids/alkalis (eg detergent). Often on hands. Erythema. - Allergic: type 4 hypersens reaction. Uncommon: often on head after dyes. Acute weeping eczema affecting margins of hairline (not scalp). Tx topical steroid Cement: can cause both together

Answer 16

Adverse effects • Teratogenicity (women should use 2 forms of contraception) • dry skin, eyes and lips/mouth (most common SE) • low mood • raised triglycerides • hair thinning • nose bleeds (due to dryness of the nasal mucosa) • intracranial hypertension (so do NOT give with tetracyclines) • photosensitivity

Answer 17

``` Features • target lesions • 1st back of the hands/feet >> torso • upper limbs (more than LLs) • pruritus is occasionally seen and is usually mild ``` 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 hypersens reaction EM major: mucosal involvement

Answer 18

- Painful skin ulceration (esp on LLs or site of minor injury/stoma) - Biopsy: dense infiltration of neutrophils Causes - idiopathic in 50% - IBD in 10-15% (UC or crohns) - rheum: RA, SLE - haem: lymphoma, myeloid leukaemias, myeloproliferative disorders, monoclonal gammopathy (IgA) - granulomatosis with polyangiitis - PBC Presentation - Sudden: small pustule, red bump or blood-blister - Then skin breaks down > painful ulcer with an edge that's purple, violaceous and undermined. ○ Ulcer may be deep and necrotic - Can get systemic syms (fever, myalgia) Dx: often clinical + histology (not specific but r/o other causes) - Ddx malignancy so refer to derm to consider biopsy Management - 1st line: oral steroids - potential for rapid progression is high in most - Difficult cases: other immunosup EG ciclosporin and infliximab any surgery should be postponed until the disease process is controlled on immunosuppression to avoid risk worsening of the disease (pathergy)

Answer 19

- Painful skin ulceration (esp on LLs or site of minor injury/stoma) - Biopsy: dense infiltration of neutrophils Causes - idiopathic in 50% - IBD in 10-15% (UC or crohns) - rheum: RA, SLE - haem: lymphoma, myeloid leukaemias, myeloproliferative disorders, monoclonal gammopathy (IgA) - granulomatosis with polyangiitis - PBC Presentation - Sudden: small pustule, red bump or blood-blister - Then skin breaks down > painful ulcer with an edge that's purple, violaceous and undermined. ○ Ulcer may be deep and necrotic - Can get systemic syms (fever, myalgia) Dx: often clinical + histology (not specific but r/o other causes) - Ddx malignancy so refer to derm to consider biopsy Management - 1st line: oral steroids - potential for rapid progression is high in most - Difficult cases: other immunosup EG ciclosporin and infliximab any surgery should be postponed until the disease process is controlled on immunosuppression to avoid risk worsening of the disease (pathergy)

Answer 20

Usually self-resolves but can give UVB phototherapy to accelerate resolution • Resolve spon in 2-3months • Topical agents as per psoriasis • UVB phototherapy Tonsillectomy if recurrent

Answer 21

- Papular lesions: often abit hyperpigmented and depressed centrally - Usually on dorsal hands and feet, extensors of arms nd legs - Ass w DM (weakly)

Answer 22

``` Mx 1. Permethrin 5% 2. Malathion 0.5% Itching for 4-6wk after eradication all household and close physical contacts should be treated at the same time, even if asymptomatic ``` Crusted (norwegian) scabies - patients with suppressed immunity, especially HIV. - crusted skin will be teeming with hundreds of thousands of organisms. Mx: Ivermectin + isolation is essential

Answer 23

- Caused by IgA deposition in dermis NOTES - Mx: gluten-free diet + dapsone PC: itchy, vesicular skin lesions on extensor surfaces (e.g. elbows, knees, buttocks) Dx = skin biopsy: direct immunofluorescence shows deposition of IgA in a granular pattern in the upper dermis

Answer 24

- If not treated can > squamous cell carcinoma NOTES - cause: over exposure to infrared radiation. - PC: reticulated, erythematous patches with hyperpigmentation and telangiectasia. Often elderly women who always sits next to an open fire.

Answer 25

Golden crusted skin lesions – usually around mouth Causes: staph aureus, strep pyogenes Mx 1st line: hydrogen peroxide 1% cream (for systemically well and low risk of complications) Next options • Topical fusidic acid • If resistant to this: topical mupirocin Extensive disease: • Oral fluclox • Pen-allergic: oral erythromycin Kids should stay off school until lesions crusted/healed OR 48h after starting abx

Answer 26

``` Classic description • Slowly growing over 2-3 months • On a sun exposed area EG nose • Round, raised, flesh coloured lesion • Central depression • Rolled edges • Telangiectasia ``` If suspect > routine referral Morphoeic BCC = firm/rough/qxy patch often on cheek, poorly defined edge. Mx: mohs surgery NOTES • Grows slowly, locally invasive - rare to metastasise • Most common cancer in western world ``` Features • most common type = nodular BCC • Sun-exposed areas esp head and neck • Initially pearly, flesh coloured papule w telangiectasia • Then can ulcerate > central crater ``` ``` Mx • Surgical removal • Curettage • Cryotherapy • Topical cream: imiquimod, fluorouracil • Radiotx ```

Answer 27

``` Classic description • Slowly growing over 2-3 months • On a sun exposed area EG nose • Round, raised, flesh coloured lesion • Central depression • Rolled edges • Telangiectasia ``` If suspect > routine referral Morphoeic BCC = firm/rough/qxy patch often on cheek, poorly defined edge. Mx: mohs surgery NOTES • Grows slowly, locally invasive - rare to metastasise • Most common cancer in western world ``` Features • most common type = nodular BCC • Sun-exposed areas esp head and neck • Initially pearly, flesh coloured papule w telangiectasia • Then can ulcerate > central crater ``` ``` Mx • Surgical removal • Curettage • Cryotherapy • Topical cream: imiquimod, fluorouracil • Radiotx ```

Answer 28

RF • Excessive sun (most common cause) or psoralen UVA therapy exposure • Actinic keratoses, bowen's • Immunosuppression EG transplant, HIV • SMOKING • Long term leg ulcers - marjolins ulcer [grows from burns/scars/badly healed wounds] • Genetic conditions EG xeroderma pigmentosum, oculocutaneous albinism Overview • Most common skin cancer • Rare to met: 2-5% Tx • If <20mm, surgical removal w 4mm margins • If >20mm, then need 6mm margins • Moh's surgery if cosmetic site or high risk pt Prognosis Good: well differentiated tumour, <20mm, <2mm deep, no other diseases Poor: poorly differentiated, >20mm, >4mm deep, immunosuppressed

Answer 29

Invasive depth of tumour = most important prognostic factor (breslow thickness)

Answer 30

Management 1. One topical (retinoid, benzoyl peroxide) 2. Combo of topicals (R, BP or topical abx) 3. Oral abx (lymecycline, oxytetracycline or doxycycline): max 3 mos a. Always give with topical R or BP - reduces risk of abx resistance dev 4. Alt to oral abx: oral COCP in women a. Use with topical agent 5. oral isotretinoin: only under specialist supervision ○ pregnancy is a contraindication to topical and oral retinoid treatment More detail on mx Abx - Tetracyclines: avoid in pregnancy, BF or <12y old - Pregnancy: use erythromycin - Gram-negative folliculitis: comp of long-term antibiotic use - tx: high-dose oral trimethoprim

Answer 31

Least drowsiness causing: loratidine Non-sedating antihistamines: loratidine, cetirizine Sedating: chlorphenamine

Answer 32

Treatment • early keloids: intra-lesional steroids e.g. triamcinolone excision is sometimes required

Answer 33

Mx 1. Refer for biopsy and confirmation Oral steroids

Dermatology Flashcards

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