Dermatology

Question 1

erythema nodosum

Answer 1

painful blue-red lesions on the anterior shin

seen in sarcoidosis, TB, Crohn’s and leprosy

Question 2

erythema multiforme

Answer 2

“target” lesions with central blisters

due to an autoimmune reaction to medications, infection, cancers (can be idiopathic)

Question 3

erythema ab igne

Answer 3

brown-y discolouration due to heat/ intra-red exposure (often seen in pts with abdo pain that use hot water bottles)
can go on to develop SCC

Question 4

dermatitis herpetiformis

Answer 4

autoimmune blistering due to IgA deposits in the dermis on the extensor surfaces
seen in coeliac disease

Question 5

lichen’s sclerosis

Answer 5

inflammatory condition that usually affects the genitals
in females is very itchy and can increase risk of vulval cancer (give topical steroids and emollients)
in males occurs in uncircumcised, results in phimosis with a white ring around it

Question 6

lichen’s planus

Answer 6

autoimmune inflammatory condition
purple, polygonal papules, pruritic (itchy)
saw tooth T-cell infiltration between dermis and epidermis
is associated with hepatitis C

Question 7

acanthosis nigricans

Answer 7

symmetrical velvety brown plaques around body creases

due to insulin resistance (so seen in T2DM, Cushing’s, PCOS, Acromegaly, etc)

Question 8

pityriasis rosea

Answer 8

acute self limiting rash often following a viral infection

begins with a herald patch then the rash develops to form a ‘Christmas tree’ distribution

Question 9

strawberry haemangioma

Answer 9

AV malformation in new-born, will regress

Question 10

cherry haemangioma

Answer 10

AV malformation that occurs with age, is benign, will not regress

Question 11

hereditary haemorrhagic telangiectasia

Answer 11

aka Osler-Weber-Rendu syndrome
is autosomal dominant
causes multiple telangiectasia over skin and mucosa

Question 12

malignant melanoma

Answer 12

Asymmetric
Border is irregular
Colours (2 or more)
Diameter (often >6mm)
Evolution of lesion 

requires excision biopsy with margin
70% of cases are superficial spreading melanoma, nodular melanoma is the most aggressive type

Question 13

squamous cell carcinoma of the skin

Answer 13

sun exposure
actinic keratoses is the premalignant version
immunosuppression, Marjolin’s ulcer, smoking, etc are risk factors

surgical excision with margin 4mm if <20mm or 6mm margin if >20mm

Question 14

basal cell carcinoma

Answer 14

most common cancer in the western world
slow growth and local invasion of a lesion on sunexposed sites - may ulcerate to leave a central crater
surgical removal, curettage, cryotherapy, topical fluorouracil and radiotherapy

Question 15

impetigo

Answer 15

superficial skin infection caused by staph aureus or strep pyrogenes
commonly in children on their faces
very contagious, golden crusted skin lesions (incubation period 4-10days)
Rx: topical fusidic acid, if extensive oral flucloxacillin
should be excluded from school until non-contagious ie 48hrs after starting treatment or when scabs have crusted over

Question 16

cellulitis

Answer 16

due to strep pyrogenes or staph aureus
Eron classification
mild-moderate: flucloxacillin +/- clindamycin
severe: IV benzylpenicillin and flucloxacillin

Question 17

necrotising fasciitis

Answer 17

medical emergency - must act FAST
needs radical debridement of tissue +/- amputation or is fatal, IV ABx (benzylpenicillin and clindamycin)
is caused by anaerobes/aerobes, clostridium or strep pyrogenes
(Fournier’s gangrene is NF localised to the scrotum and perineum)

Question 18

Steven-Johnsons Syndrome

Answer 18

toxic epidermal necrolysis - allergic reaction to medication or infection (fatal in 5%) 
drug causes : PCP LAPSE
phenytoin 
carbamazepine 
Phenobarbital 
Lamotrigine
Allopurinol
Penicillin 
Sulfa drugs 
Erthromycin

Question 19

Acne vulgaris

Answer 19

occurs in up to 90% of adolescents
- -follicular epidermal hyperproliferation causes a keratin plug, this obstructs the pilosebaceous follicle allowing colonisation of anaerobic bacterium (Propionibacterium acnes) resulting in inflammation, comedones and pustules
Rx: topical OTC benzoyl peroxide, retinoids, ABx
oral ABx (doxycycline if bad)
COCP may help some
specialist can prescribe oral isotretinoin (teratogenic and increases suicide risk, need to monitor LFTs)
THERE IS NO ROLE FOR DIETARY MODIFICATION

Question 20

acne fulminans

Answer 20

is a very severe acne with associated systemic upset, requires hospital admission for oral steroids

Question 21

acne rosacea

Answer 21

is a chronic condition that affects the nose, cheeks and forehead
flushing, telangiectasia, blepharitis with persistent erythema, papules and pustules
Rx: mild - topical metronidazole, oral oxytetracycline if more severe, high factor daily sunscreen
laser therapy is prominent telangiectasia

Question 22

treatment of fungal nail

Answer 22

oral terbinafine

Question 23

shingles

Answer 23

reactivation of herpes zoster virus causing a painful, blistering rash of dermatomal distribution
vaccine is live-attenuated so CI in immunocompromised
Hutchinson’s sign (vesicles on tip of nose) indicate ophthalmic shingles will develop - requires specialist referral
Ramsey-Hunt syndrome = shingles of the facial nerve

Rx: oral acyclovir

Question 24

urticaria

Answer 24

dermal swellings - “wheals”
acute <6 weeks - can be due to type 1 hypersensitivity reaction e.g. due to penicillin, cephalosporins, nuts, shellfish and eggs
(chronic >6 weeks usually idiopathic, avoid drugs that promote mast cell degranulation)
treatment: diphenhydramine (antihistamine)
drugs that promote mast cell degranulation = aspirin, NSAIDs, opioids and iodinated contrast

Question 25

vitiligo

Answer 25

autoimmune destruction of melanocytes resulting in depigmentation of the skin Rx: sun protection, topical corticosteroids if applied early, can depigment the unaffected area if widespread

Question 26

eczema

Answer 26

IgE associated Rx: topical emollients, steroids oral antihistamines, flucloxacillin, steroids or azathioprine in severe cases

Question 27

psoriasis

Answer 27

most commonly plaque psoriasis T-cell driven inflammation due to chronic keratinocyte hyperproliferation which causes chronic erythematous scaly patches (mainly on extensor surfaces), exacerbated by trauma, alcohol, beta-blockers, lithium, NSAIDs, and steroid withdrawal Rx: potent corticosteroids ad vitamin D analogues and emollients

Question 28

guttate psoriasis

Answer 28

frequently triggered by a strep infection | causes multiple red, teardrop lesions

Question 29

complications of psoriasis

Answer 29

psoriatic arthropathy (psoriatic arthritis) increased incidence of metabolic syndrome increased incidence of CVD increased incidence of VTE psychological distress

Question 30

dermatomyositis

Answer 30

inflammatory disorder causing symmetrical, proximal muscle weakness and characteristic skin lesions associated with CT disorders or underlying malignancy (ovarian, breast, lung) ANA positive and anti-Jo1 antibody Rx: systemic corticosteroid (polymyositis = the same without the typical skin features)

Question 31

Peutz-Jeghers Syndrome

Answer 31

``` autosomal dominant (STK11) condition characterised by numerous harartomatous polyps in the GI tract and associated pigmented "freckles" on the lips, face, palms and soles ~50% die from a GI cancer by 60 yers ```

Question 32

Raynaud's phenomenon

Answer 32

Raynaud's disease is idiopathic and less severe Raynaud's phenomenon is caused by CT/vascular/haematological disease triphasic: WHITE, BLUE then RED Rx: nifedipine (CCB)

Question 33

Ehlers-Danlos syndrome

Answer 33

autosomal dominant CT disorder affecting type III collagen --> joint hypermobility and elasticity

Question 34

Marfans syndrome

Answer 34

autosomal dominant condition - defect of FBNI gene on chromosome 15 that codes for fibrillin-1 arm span:height ratio >1.05 death is often due to aortic dissection Rx: annual ECHO, aneurysm repair when aortic diameter >5cm, beta-blockers and ACEi

Question 35

Pellagra

Answer 35

due to niacin (B3) deficiency or due to isoniazid | features: dermatitis, diarrhoea, dementia, depression and death if not taking

Question 36

Leucoplakia

Answer 36

is a diagnosis of exclusion | a premalignant condition - hard white spots on mucous membranes that can't be rubbed off

Question 37

Bullous pemphigoid

Answer 37

autoimmune condition with sub-dermal blistering of the skin (no mucosal involvement)

Question 38

Pemphigus vulgaris

Answer 38

autoimmune destruction against desmoglein-3 mucosal ulceration is usually the first sign Rx: steroids and immunosuppression

Question 39

keratoacanthoma

Answer 39

a benign epithelial tumour, common with age, needs to be excised as differential is SCC

Question 40

pityriasis versicolour

Answer 40

superficial cutaneous fungal infection caused by malassezia furfur more noticeable following a suntan Rx: topical ketoconazole