Dermatology

Question 1

Teardrop shaped rash after a throat infection?

Answer 1

Guttate psoriasis

Typically itchy but not painful

Gutta = drop in Latin (rainDROPS collected in GUTTERS)

Question 2

Treatment for localised impetigo?

Answer 2

Hydrogen peroxide 1% cream

Question 3

Treatment for dermatophyte nail infections?

Answer 3

Oral terbinafine

Dermatophyte accounts for 90% of nail infections

6w-3m for fingernails
3m-6m for toenails

Question 4

Slow-growing, red, scaly patches on sun-exposed area?

Answer 4

Think Bowen’s disease (SCC in situ, the precancerous lesion)

Tx = topical 5-fluorouracil, cryotherapy, or excision

Question 5

Differentials for itchy, blistering rash?

Answer 5

No mucosal involvement = bullous pemphigoid

Mucosal involvement = pemphigus vulgaris

Question 6

Itchy, papular rash on…

palms, soles, genitals, or flexor surfaces of arms?

Answer 6

Lichen planus

Question 7

Treatment for lichen planus?

Answer 7

Potent topical steroids (e.g. betamethasone)

Question 8

Pregnant woman with a widespread rash, sparing her periumbilical area?

Answer 8

Polymorphic eruption of pregnancy

Tx = emollients ⇒ mild topical steroids ⇒ oral steroids

Question 9

Most common side effect of isotretinoin?

Most important side effect?

Answer 9

Dry skin

Intracranial haemorrhage (never co-prescribe with tetracyclines), very low mood/suicidal ideation, teratogenicity (2 forms of contraception needed)

Question 10

Mildly itchy hypopigmented patches on trunk?

Answer 10

Pityriasis versicolor

Patches may be hypopigmented, pink, or brown (hence ‘versicolor’)

Tx = topical anti fungal (ketoconazole)

Question 11

Rosacea treatment

Answer 11

Mild/moderate = topical metronidazole
Severe/resistant = oral tetracycline

Early sx = rosacea
Over time = persistent erythema with papules + pustules