Dermatology Flashcards
how does erythema nodosum heal
without scarring in 1-2 MONTHS
causes of erythema nodosum
Infection: strep, TB Pregnancy Systemic disease: sarcoid, IBD, behcet's Drugs: COCP, sulphonamides, penicillin Malignancy/lymphoma
what skin lesion? Slowly growing over 2-3 months On a sun exposed area Round, raised, flesh coloured lesion Central depression Rolled edges Telangiectasia
nodular BCC
tx of BCC
Surgical removal Curettage Cryotherapy Topical cream: imiquimod, fluorouracil Radiotx
non-healing ulcer at site of burn injury = what disease
SCC
RF for SCC
Excessive sun 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
tx of scc
if <20mm, surgical removal w 4mm margins
If >20mm, then need 6mm margins
Moh’s surgery if cosmetic site or high risk pt
poor prognostic indicators for scc
Good: well differentiated tumour, <20mm, <2mm deep, no other diseases
Poor: poorly differentiated, >20mm, >4mm deep, immunosuppressed
what has a herald patch
pityriasis rosea
sore throat then 2wks later widespread rash w Multiple erythematous lesions <1cm diameter Covered in fine scale
guttate psoriasis
cause & mx of guttate psoriasis
Cause : Strep infection 2-4wks prior
Tear drop papules on trunk and limbs
Mx Resolve spon in 2-3months Topical agents as per psoriasis UVB phototherapy Tonsillectomy if recurrent
mx of pityriasis rosea
Features
HERALD PATCH
Then 1-2 wks later: multiple erythematous slightly raised oval lesinos w fine scale on outer aspect of lesions
Can be classic distribution of fir tree
Mx: Self resolves after 6wks
?malignant acantosis nigricans - most important Ix to do
OGD (+ CT) - most common cancer is GI adenocarcinoma
causes of acanthosis nigricans
T2DM
GI cancer
Obesity
PCOS
Acromegaly
Cushing’s
Hypothyroid
Familial
Prader-willi
Drugs: COCP, nicotinic acid (aka niacin, tx for b3 deficiency)
acanthosis nigricans description
& malignant AN fts
AN = symmetrical brown velvety plaques in neck/axilla groin
Malignant AN
more likely when older pt & rapid onset
More typical to get itchy lesion w involvement of palms/soles/mucosa
OGD + CT for ?gastric cancer (RF: smoking, male)
Description in Q for malignant
Rapidly growing itchy rash
Mainly axilla, but also hands and soles of feet
Thickened patches of skin; discoloured (light brown)
Skin tags aroudn the lesions
Small finger-like projections from lips
33y old M recurrent nose bleeds, ID anaemia, SOB – found to have pulmonary AV malformation - ?most likely dx
hereditary haemorrhagic telangiectasia
HHT diagnostic criteria (hereditary haemorrhagic telangiectasia)
4 criteria.
Spontaneous recurrent nosebleeds
Telangiectases - multiple at characteristic sites (lips, mouth, fingers, nose)
Visceral lesions: EG GI telangiectasia, pulmonary AV malformations
1st degree relative with it
If have 2 = possible HHT
If 3 = definite
hereditary haemorrhagic telangiectasia - cause?
Genetic fts
AD
20% occur spon without FHx
TEN causes
Phenytoin
Sulphonamides
Allopurinol
Penicillins
Carbamazepine
NSAIDs
TEN mx
Stop causative drug
Supportive care – usually ITU – volume loss and electrolyte derangement need tx
IV Ig now used 1st line
Sometimes use: immunosuppresion (cyclosporin, cyclophosphamide), plasmapheresis
Positive nikolskys sign - what is it and what disease
TEN
Positive nikolskys sgin – epidermis seperates with mild lateral pressure
features of TEN
Systemically unwell: fever, tachycardic
Positive nikolskys sgin – epidermis seperates with mild lateral pressure
widespread red rash > now large fluid filled blisters 30% body surface area
psoriasis triggers and complications
Factors may exacerbate psoriasis: • trauma • alcohol • drugs: b-blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs, ACE i, infliximab • withdrawal of systemic steroids
Complications
• psoriatic arthropathy (10%)
• increased incidence of metabolic syn, CV disease and VTE
psoriasis mx
Summary
- Face, flexural and genital: Mild or moderate steroid OD or BD for max 2 weeks - Scalp 1st line: potent topical steroid OD for 4wks - Chronic plaque 1st line: potent topical steroid OD + topical vitamin D analogue OD. (one AM, one eve) - for up to 4wks
Chronic plaque mx
Throughout: regular emollients (reduce scale loss and itching)
1. 1st line: potent topical steroid OD + topical vitamin D analogue OD. (one AM, one eve) - for up to 4wks
2. 2nd line: no improvement after 8wks: vitamin D analogue BD
3. 3rd line: no improvement by 8-12wks:
○ Topical steroid BD for up to 4 weeks
○ OR Coal tar prep OD or BD
- Short-acting dithranol can also be used
Scalp
• Potent topical steroid OD for 4 weeks
If no improvement: either use a different formulation of it and/or topical agents to remove the adherent scale (EG having salicyclic acid, emollients and oils) before putting on the steroid
venous ulceration
- useful Ix? normal and abn values?
- where are they ususally?
- mx?
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)
systemic mastocytosis
- fts
- dx
- 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
pityriasis versicolor cause tx features rf
- 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
alopecia areata mx
Mx: watchful waiting for spontaneous remission Other treatment options include: • topical or intralesional corticosteroids • topical minoxidil • phototherapy • dithranol • contact immunotherapy • wigs
seborrhoeic dermatitis
- fts
- ass w ?
- comps: 2
- 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
lichen sclerosus - fts - dx - mx risk of?
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
eczema herpeticum
- causes
- mx
- presentation
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
rosacea mx
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
pemphigus vulgaris v pemphigoid
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
Koebner phenomenon ?
Koebner phenomenon (new skin lesions at the site of trauma)
Lichenoid drug eruptions - causes:
• gold
• quinine
Thiazides
pregnancy skin related lesions 4
- 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.
niacin deficiency
- what vitamin is it
- fts
- other name
- causes
Niacin/nicotinic acid (b3 def): dermatitis, diarrhoea and dementia
Can be due to isoniazid
More common in alcoholics.
erythema nodosum
fts
causes
mx
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
allergic v irritant contact dermatitis
- 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
- Allergic: type 4 hypersens reaction. Uncommon: often on head after dyes. Acute weeping eczema affecting margins of hairline (not scalp). Tx topical steroid
retinoids SE
- what do you not prescribe them with
- most common SE
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
erythema multiforme
- describe
- causes
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
pyoderma gangrenosum fts causes dx mx
- 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)
pyoderma gangrenosum fts causes dx mx
- 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)
mx of guttate psoriasis
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
granuloma annulare
- Papular lesions: often abit hyperpigmented and depressed centrally
- Usually on dorsal hands and feet, extensors of arms nd legs
- Ass w DM (weakly)
scabies mx
- normal
- norwegian
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
dermatitis herpetiformis
- cause
- fts
- mx
- 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
erythema ab igne
- fts
- cause
- risk?
- 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.
impetigo
fts
causes
mx
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
BCC
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
BCC
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
SCC
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
most important prognostic factor in melanoma
Invasive depth of tumour = most important prognostic factor (breslow thickness)
acne mx
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
anti histamines
- one that causes least drowsiness
- generally sedating (1)
- non sedating 2
Least drowsiness causing: loratidine
Non-sedating antihistamines: loratidine, cetirizine
Sedating: chlorphenamine
keloid mx
Treatment
• early keloids: intra-lesional steroids e.g. triamcinolone
excision is sometimes required
bullous pemphigoid mx
Mx
1. Refer for biopsy and confirmation
Oral steroids
