Dermatology 1

Question 1

Bullous impetigo pathogenesis?

Severe form of bullous impetigo called?

Answer 1

Toxins from staph aureus disseminates to the skin
(Exfoliative Toxin A) - targets Toxin A

Staph Aureus Scaled Skin syndrome (SSSS)

Question 2

In HIV patients
Commonest drug to cause skin reaction is?
Nevirapine causes what?

Answer 2

Commonest skin reaction induced by rash = Bactrim

Nevirapine = SJS

Question 3

Lipoatrophy of face and buffalo hump causes by what drug in HIV treatment and how to resolve it?

Answer 3

Stavudine/ Zidovudine

Change it to Lamivudine

Question 4

Neutrophilic eccrine hidradenitis caused by what chemo drug?

clinical presentation

Answer 4

Cytarabine - usually 1 week after chemotherapy

Non-specific skin rash, fever
self limiting

Question 5

What do you give in SJS/TEN?

Answer 5

IVIG

Adult burns unit referral

Question 6

Bullous pemphoid a/w what?

Answer 6

Malignancy

Question 7

Erythema nodosum is what type of hypersensitivity?

Answer 7

Type IV

Question 8

BRAFv600 mutation causes what skin disorder?

Answer 8

Benign naevus ( mole)

• to become melanoma, needs mutation in
• TERT
• CDKN2A
• PTEN/TP53

Question 9

When need SNL biopsy in melanoma?

Answer 9

Breslow thickness > 1 mm

Question 10

DRESS rash - describe it?

Answer 10

Morbiliform rash - maculopapular ( like measles)

Question 11

AGEP - what is the cause?

Answer 11

Drug causing T cells activating neutrophils

Question 12

SSSS - what is spared?

Do they have Nicolsky sign like TEN/SJS?

Answer 12

Mucous membrane

Rash goes usually around mouth, neck, perineum, axilla

-Yes

Question 13

SJS/TEN - describe rash?

Answer 13

Rash starts trunk - rapidly goes everywhere
SPARE PALMS/SOLES/SCALP

-Can be blisters/macules/targetoid

Question 14

Meningococcal rash- usually where?

Answer 14

Bilateral acral purpura

Question 15

What is the pustulated pathogenesis of SJS/TEN?

Answer 15

1. CD8 T cells kill each other via Fas-FasL pathway = apoptosis - targets keratinocytes
2. Perforin and granzyme - target cell

Question 16

Blood vessels, lymphatics found in which part of sckin?

Answer 16

Reticular dermis ( lower part of dermis) has blood vessels and lymphatics

-papillary is ( upper part of dermins)

Question 17

if have facial flushing and telagiecstasia esp. upon exposure to sun light BUT NOT SLE - what is the ddx?

Tx?

Answer 17

Rosacea - commonly have Keratitis, then phymatous of nose

Tx
1. Topical brimimodine/ oxymetazoline = block alpha receptors to reduce vascular symptoms
2. tetracyclines (2d line)
3.

Question 18

Scabies rash is what type of hypersensitivy?

Answer 18

Type IV hypersensitivity with HIGH IgE/G

Question 19

What organ transplant likely cause skin cancer?

Answer 19

Lung and heart transplant

Question 20

UVA light causes what?

UVB light causes what?

Answer 20

UV A - age spots/ solar lentigo

UV B - sunburn/ MELANOMA

But Both UV causes skin cancer