Dermatology

Question 1

chondrodermatitis nodularis helicis

Answer 1

benign painful nodule on top of ear
more common in men

Question 2

erythema nodosum

Answer 2

inflammation of subcut fat
tender erythematous nodules
normally on shins
resolve in 6 weeks
non scarring

causes-
infections
sarcoid
becets
IBD
PREGNANCY

Question 3

dermatofibroma/histiocytoma

Answer 3

benign
often precipitated by injury
single firm papule/nodule

skin DIMPLES on pinching

can look similar to BCC

Question 4

Melanoma major/minor diagnostic criteria

Answer 4

Change in-
size
shape
colour

diameter >6mm
inflammation
oozing
altered sensation

Question 5

Margin thickness based on Breslow depth for melanoma

Answer 5

0-1mm = 1cm
1-2mm = 1-2cm
2-3mm = 2-3cm
>3mm = 3cm

Question 6

acne in pregnancy

Answer 6

dont use tetracyclines

use erythromycin instead

also this in children <12

Question 7

mild-mod acne

Answer 7

12 week course of-

topical adapalene with topical benzoyl peroxide

topical tretinoin with topical clindamycin

topical benzoyl peroxide with topical clindamycin

Question 8

mod-severe acne

Answer 8

a 12-week course of -
topical adapalene with topical benzoyl peroxide
topical tretinoin with topical clindamycin
topical adapalene with topical benzoyl peroxide + lymecycline or doxycycline
a topical azelaic acid + either oral lymecycline or oral doxycycline

isotretinoin/roaccutain only specialist use

Question 9

duration of PO ABX treatment acne

Answer 9

6 months max

Question 10

complication of long term ABX use in acne

Answer 10

gram negative folliculitis

use high dose trimethoprim

Question 11

acne alternatives to creams/ABX

Answer 11

COCP in women
combine with topical agents

dianette/co-cyprindiol can be used

BUT

increased risk of VTE so second line
only use max 3 months

Question 12

shingles

Answer 12

give PO antivirals if <72 hrs since onset
- unless <50, no risk factors, mild

famciclovir/valacyclovir first line

aciclovir second line

antivirals reduce incidene post herpetic neuralgia

Question 13

auspitz sign

Answer 13

picking off white scale in psoriasis exposes red membrane underneath that can bleed

Question 14

rosacea

Answer 14

nose cheeks forehead
FLUSHING (often with alcohol)
telangiectasias
erythema with papules later
blepharitis

Rx-
flushing/erythema - brimonidine

papules - ivermectin

severe papules add doxy

Question 15

leukoplakia

Answer 15

white patches in mouth

DIAGNOSIS OF EXCLUSION

must rule out lichen planus and SCC

up to 20% cases can transform to SCC

Question 16

port wine stain

Answer 16

dark red
do not get better
associated with vascular abnormalities like sturge-weber sydrome

Question 17

hereditary hemorrhagic telangiectasia

Answer 17

osler-weber-rendu syndrome

autosomal dom

multiple telangiesctasia all over

diagnostic criteria-
1. multiple telangiectasias
2. frequent recurent nosebleeds
3. visceral lesions - AVMs anywhere
4. family history

if has 2 - possible diagnosis
if has 3+ - definite diagnosis

Question 18

Nikolskys sign

Answer 18

epidermis seperates with mild lateral pressure

seen in TEN

Question 19

TEN - toxic epidermal necrolysis

Answer 19

scalded appearance

systemically unwell - fevers,tachy

Nikolskys sign positive

normally drug caused-
phenytoin
allopurinol
penicillins
carbamazapine

IVIG first line

Question 20

pretibial myxodema

Answer 20

symmetrical erythematous lesions over shins
shiny orange peel skin

seen in thyrotoxicosis/graves