Dermatology

Question 1

Classic presentation of dermatitis herpetiformis

Answer 1

itchy papules and vesicles on extensor surfaces

Question 2

diagnosis of dermatitis herpetiformis

Answer 2

immunoflorescence shows IgA deposits in the upper dermis

Question 3

Management of dermatitis herpetiformis

Answer 3

gluten free diet

dapsone

Question 4

acne rosacea treatment

Answer 4

mild/moderate - topical metronidazole

severe/resistant - oral tetracycline

Question 5

features of acne rosacea:

where it affects, type of lesions

Answer 5

cheek face and forehead
initially flushing , telangectesia are common,
later develops into persistent erythema with papules and pustules
can lead to rhinophyma, and my have blepharitis

Question 6

causes of erythema multiforme

Answer 6

• viruses: HSV (in 50% of cases), Orf (parapox virus)
• idiopathic
• bacteria: Mycoplasma, Streptococcus
• drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, OCP, nevirapine
• connective tissue disease e.g. SLE
• sarcoidosis
• malignancy

Question 7

features of erythema multiforme

Answer 7

target lesions
usually start on backs of hands/feet then spread to torso
more commonly upper limbs than lower limbs
mild pruritis

Question 8

Definition of onycholysis

Answer 8

separation of the nail plate from the nail bed

Question 9

Causes of onycholysis

Answer 9

trauma
infection esp fungal
skin disease eg psoriasis, dermatitis
impaired circulation eg Raynauds
hypo/hyper-thyroidism

Question 10

Vitiligo:

• aeteology
• age of onset
• features

Answer 10

autoimmune loss of melanocytes –> hypopigmentation
1% of population, starts in 20-30s
well demarcated patches of depigmented skin, usually peripheries, trauma may precipitate new lesions (Koebner phenomenon)

Question 11

Vitiligo associated conditions

Answer 11

T1DM
Addisons disease,
Autoimmune thyroid disorders,
Pernicious anaemia,
Alopecia areata

Question 12

Management of vitiligo

Answer 12

sun block

topical steriods if applied early

Question 13

Main complication of PUVA therapy for psoriasis

Answer 13

SCC

Question 14

features of pyoderma gangrenosum

Answer 14

small papule ->deep red necrotic ulcer with violaceous border (gun metal grey)
typically on lower legs
may have systemic upset (fever, myalgia)

Question 15

causes of pyoderma gangrenosum

Answer 15

idiopathic
IBD 
RA, SLE
myeloproliferative disorders
lymphoma, myeloid leukaemias
monoclonal gammopathy (IgA)
primary biliary cirrhosis (DR3)

Question 16

Mx of pyoderma gangrenosum

Answer 16

oral steroids +/- other immunosuppressants (eg infliximab)

Question 17

Acanthosis nigricans disease associations

Answer 17

endo: diabetes mellitus, Cushing's disease, hypothyroid, acromegaly
UC
gastric cancers
PCOS
obesity
Prader-Willi syn
drugs: OCP, nicotinic acid

Question 18

features and pathology of lichen sclerosus

Answer 18

inflammation of epidermis of genitals leads to atrophy and formation of itchy white plaques.
More common in elderly females

Question 19

Mx of lichen sclerosus

Answer 19

biopsy to exclude other conditions (increased risk of vulval cancer)
topical steroids and emollients

Question 20

features of lichen planus

Answer 20

purple papules that are pruritic
white cracks over the top (Wickham’s striae)
oral involvement common.

Question 21

features of toxic epidermal necrolysis?

commonly due to

Answer 21

scalded appearance with friable epidermis
systemic upset - pyrexia, tachycardia
most commonly due to a drug reaction (penicillin, phenytoin, allopurinol, carbamazepine)

Question 22

common drug precipitants of TEN?

Answer 22

phenytoin,
allopurinol
penicillins
carbamazepine

Question 23

causes of scarring alopecia

Answer 23

trauma, burns, radiotherapy
lichen planus
discoid lupus
tinea capitis (if a kerion develops)

Question 24

causes of non-scarring alopecia

Answer 24

male pattern baldness
drugs: cytotoxic, carbimazole, heparin, OCP, colchicine
nutritional:iron and zinc def
autoimmune: alopecia areata
telogen effluvium (hair loss following stressful time)
trichotillomania (pulling hair out)

Question 25

classical features of pretibial myxoedema

Answer 25

symmetrical erythematous shin lesions with shiny orange peel skin
seen in Graves disease

Question 26

classical features of Necrobiosis lipoidica diabeticorum

Answer 26

shiny, painless areas of yellow/red skin typically on the shin of diabetics
often associated with telangiectasia

Question 27

Exacerbating factors for psoriasis

Answer 27

withdrawal of steroids
trauma
alcohol
beta blockers, lithium, NSAIDS, ACEi, antimalarials

Question 28

Features of bullous pemphigoid

Answer 28

Itchy tense blisters, typically around flexures
Blisters heal without scarring
Rarely involves mucous membranes (NB differentiating feature with pemphigus)

Question 29

Ix and Mx of bullous pemphigoid

Answer 29

Skin biopsy - IgG and C3 deposits at dermoepidermal junction

Oral corticosteroids

Question 30

What are myxoid cysts and where are they usually found?

Associations?

Answer 30

Benign ganglion cysts on the dorsum of a distal phalanx
Usually have OA in surrounding joint
In middle aged females

Question 31

Complications of psoriasis

Answer 31

Psoriatic arthritis
Superimposed bacterial infection
Metabolic syndrome
Cardiovascular disease
VTE

Question 32

Pathology of bullous pemphigoid

Answer 32

Autoantibodies against hemidesmosomal proteins BP180 and BP230

Question 33

Features of drug hypersensitivity syndrome

Mx

Answer 33

3-6 weeks after starting anticonvulsants or antimicrobials
fever, facial oedema, papulopustular rash, lymphadenopathy or hepatitis
associated eosinophilia
Rx with oral steroids

Question 34

Association of necrolytic migratory erythema

Answer 34

glucagonoma