Dermatology Flashcards
complications associated with acne rosacea?
rhinophyma,
ocular: blepharitis
management of acne rosacea with limited number of pustules/ papules, no plaques?
topical metronidazole
management of acne rosacea with predominant flushing but limited telangiectasia?
consider topical brominidine gel
management of severe acne rosacea?
systemic antibiotics e.g oxytetracycline
management of acne rosacea with prominent telangiectasia?
laser therapy
management of SCC <20mm in diameter?
excision with 4mm margins
*mohs micrographic surgery may be used in high risk patients and in cosmetically impt sites
management of SCC >20mm in diameter?
excision with 6mm margins
*mohs micrographic surgery may be used in high risk patients and in cosmetically impt sites
Good prognostic factors of SCC?
- well differentiated
- <20mm diameter
- <2mm deep
- no associated diseases
Poor prognostic factors of SCC?
- poorly differentiated
- > 20mm diameter
- > 4mm deep
- immunosuppression
what bacteria is implicated in acne vulgaris pathology?
Anaerobic bacteria: Propionibacterium acnes
What may cause obstruction of the pilosebaceous follicle leading to acne vulgaris?
follicular epidermal hyper proliferation -> keratin plug
-> obstruction of pilosebaceous follicle
Patient on TPN + perioriicial dermatitis, alopecia, acrodermatitis?
Zinc deficiency
- TPN patients do not receive zinc
what antibiotic predisposes to pellagra?
isoniazid
- isoniazid inhibits the conversion of tryptophan -> niacin
what drugs may cause lichen planus?
- gold
- quinine
- thiazides
1st line management of scabies?
permethrin 5%
management of crusted scabies?
Ivermectin
- crusted skin will be teeming with hundreds of thousands of organisms
- seen in pts with suppressed immunity, esp HIV
management of crusted scabies?
Ivermectin
- crusted skin will be teeming with hundreds of thousands of organisms
- seen in pts with suppressed immunity, esp HIV
Erythema nodosum with no other past medical history, what is a useful investigation?
CXR- can help exclude sarcoidosis, TB
shiny orange peel skin over shins?
pretibial myxoedema
- seen in Graves disease
initially small red papule, -> later deep, red, necrotic ulcers with a violaceous border on shins
pyoderma gangrenous
- idiopathic in 50%, IBD, myeloproliferative disease, connective tissue diseases
shiny, painless areas of yellow/red skin typically on the shin of diabetics
- often assoc w telangiectasia
Necrobiosis lipoidica diabeticorum
acanthosis nigricans assoc w which kind of GI cancer?
gastric adenocarcinoma
management of lichen sclerosus?
topical steroids, emollients.
- If atypical features present, biopsy.
causes of scarring alopecia?
- trauma, burns
- radiotherapy
- lichen planus
- discoid lupus
- tinea wapitis
drugs causing non scarring alopecia?
cytotoxic drugs, carbimazole, heparin, COCP, colchicine
what nutritional deficiencies may cause non scarring alopecia?
iron, zinc deficiency
extensive umbilicated lesions in HIV?
molluscum contagiosa
extensive umbilicated lesions in HIV?
molluscum contagiosum
what is systemic mastocytosis?
neoplastic proliferation of mast cells
features of systemic mastocytosis?
- urticaria pigmentosa - produces a wheal on rubbing (Darier’s sign)
- flushing
- abdominal pain
- monocytosis on the blood film
diagnosis of systemic mastocytosis?
raised serum tryptase,
high urinary histamine
Darier’s sign?
systemic mastocytosis
- produces a wheal on rubbing
1st line management of chronic plaque psoriasis?
topical potent steroid + vit D analogue
- should be applied separately, ie. one in the morning, and the other in the evening
2nd line management of chronic plaque psoriasis (if no improvement of 8 wks of 1st line treatment)?
Vit D analogue BD
Management of scalp psoriasis?
potent topical steroids OD for 4 wks
Management of face, flexural, genital psoriasis?
mild/ mod potency topical steroids for max of 2 wks
1st line management of dermatophyte nail infection
oral terbinafine (itraconazole as alternative)
- 1.5- 3 mo for fingernails
- 3- 6 mo for toenails
management of candida nail infection?
mild- topical anti fungal (amorolfine)
severe- oral itraconazole
fingernails - 6 mo
toenails - 9-12 mo
causes of Stevens Johnsons syndrome?
penicillin, sulphonamides
- anti-epileptics: lamotrigine, carbamazepine, phenytoin
- allopurinol
- NSAIDs
- OCP
Pigmentation of nail bed affecting proximal nail fold (Hutchinson’s sign)?
Acral lentiginous melanoma
what malignancy is associated with Necrolytic migratory erythema?
glucagonoma
pemphigus vulgaris: antibodies directed against?
desmoglein -3
1st line management of pyoderma gangrenosum?
oral steroids
pemphigoid: antibodies directed against?
hemidesmosomal proteins BP180 and BP230
monomorphic punched-out erosions (circular, depressed, ulcerated lesions) usually 1–3 mm in diameter
eczema herpeticum
what may precipitate pompholyx eczema?
humidity e.g. sweating, high temps
conditions associated with seborrhoeic dermatitis?
HIV, Parkinson’s disease
1st line treatment of Toxic Epidermal necrolysis?
IVIG
erythema nodosum: usually heals within?
6 wks
drugs known to exacerbate psoriasis?
- beta blockers,
- lithium,
- antimalarials (chloroquine and hydroxychloroquine),
- NSAIDs and ACE inhibitors,
- infliximab
what virus is associated with pityriasis rosea?
HHV-7
photosensitive rash on face/ hands + hypertrichosis + hyperpigmentation?
porphyria cutanea tarda
management of porphyria cutanea tarda?
- chloroquine
- venesection: preferred if iron ferritin is above 600 ng/ml
asymptomatic, flat, slightly scaly, pink or brown rash usually found in the groin or axillae
erythrasma
- caused by overgrowth of the diphtheroid Corynebacterium minutissimum
examination of erythrasma?
Wood’s light: coral-red fluorescence
management of erythrasma?
topical miconazole, or antibacterial.
if extensive infection: oral erythromycin
what bacteria is isolated in erythrasma?
Corynebacterium minutissimum
management of early keloids?
intra lesions steroids e.g. triamcinolone
most common sites for keloid scars?
in decreasing frequency:
- sternum
- shoulder
- neck
management of facial hirsutism not responding to cocp?
topical eflornithine
- CI in preg/ breastfeeding
papular lesions that are often slightly hyperpigmented and depressed centrally
+ typically on hands / feet, extensor surfaces
granuloma annulare
- assoc DM
drug causes of hypertrichosis?
minoxidil, ciclosporin, diazoxide
most common cause of tinea capitis in the UK?
Trichophyton tonsurans
which tetracycline is less used due to possibility of irreversible skin pigmentation?
minocycline
erythema ab igne increases risk of…?
SCC
moderate potency topical steroids?
betametasone valerate 0.025% (Betnovate RD)
clobetasone butyrate 0.05% (Eumovate)
potent topical steroids?
Betnovate= Betametasone valerate 0.1%, Cutivate = fluticasone propionate 0.05%
very potent topical steroids?
Dermovate = clobetasol propionate 0.05%
management that can help accelerate the clearance of guttate psoriasis?
UVB phototherapy
Management of dermatitis herpetiformis?
Gluten free diet
Dapsone topical
2nd line mx of dermatitis herpetiformis after treatment w gluten free diet +|- dapsone?
Sulfapyridine
Diagnostic criteria for NF1?
- at least 6 cafe au last spots/ hyperpigmented macules (at least 15mm in adults, 5mm in <10yos)
- axillary or inguinal freckles
- two or more typical neurofibromas or 1 plexiform neurofibroma
- optic nerve glioma
- 2 or more iris hamartomas (Lisch nodules seen on slit lamp)
- sphenoid dysplasia or typical long bone abnormalities such as arthorsis
