Dermatology

Question 1

What is the alternative name for ring worm?

Answer 1

Tinea Corporis

Question 2

What is the cause of ringworm?

Answer 2

Dermatophyte infection - microsporum Canis

Question 3

What is the cause of tinea capitus?

Answer 3

Fungal scalp infection - caused by trichophyton

Question 4

How does ring worm tend to present?

Answer 4

Annular, erythematous scaly lesion - pruritic border and clear centre - typically presents on the arm s

Question 5

Which toxins are associated with staphylococcal scalded skin?

Answer 5

Epidermolytic toxins A&B

Known as exfoliative toxins which disrupt the layer between the stratum spinosum and the stratum granulosa

Question 6

Which toxin is commonly implicated in food poisoning causing gastroenteritis?

Answer 6

Staphylococcal enterotoxin A

Question 7

What is lichenification?

Answer 7

Thickening of the epidermis with exaggerated skin markings

Seen in eczema

Question 8

What is dermographism?

Answer 8

The phenomenon of scratching which causes the formation of erythematous wheals within the dermis of the skin

Seen in urticaria

Question 9

What is acanthosis?

Answer 9

Thickening of the skin with marked proliferation of keratinocytes in the epidermis

Seen in psoriasis

Question 10

What is Kobner Phenomenon?

Answer 10

The formation of skin lesions at sites of trauma or scarring

Seen occasionally in psoriasis

Question 11

What is parakeratosis?

Answer 11

The retention of nuclei in the stratum corneum due to keratinocytes maturing and proliferating so rapidly

Specific to psoriasis

Question 12

Keloid scarring is over activity of which cell type?

Answer 12

Fibroblasts

Question 13

What is the site of the blisters in pemphigoid?

Answer 13

Subepidermal

Hence tense robust blisters

Question 14

What is the site of the blisters in pemphigus?

Answer 14

Intra-epidermal

Hence flaccid and easily broken blisters

Question 15

What is the pathophysiology of pemphigus?

Answer 15

Results from autoantibodies against desmogleins

Question 16

Which conditions are associated with Steven Johnson Syndrome?

Answer 16

Herpes Simplex Virus
Mycoplasma pneumoniae infection
HIV
Being immunocompromised
Previous Hx of SJS
Drug sensitivities (e.g. penicillins, phenytoin, COCP)

Question 17

What virus causes Roseola Infantum?

Answer 17

HHV 6 - most commonly

Can also be caused by adenovirus and enterovirus

Question 18

What are the features of roseola infantum?

Answer 18

Classically high fever

Followed by a blanching, maculopapular rash which occurs once the fever subsides

Question 19

Which virus is associated with a rash formation when treated with amoxicillin?

Answer 19

EBV

Question 20

Describe the pathophysiology of vitiligo?

Answer 20

Autoimmune aetiology affecting melanocytes (melanocytes reside in the epidermis)

Question 21

Describe the histopathological appearance in alopecia areata?

Answer 21

Characterised by T cells within the peribulbar infiltrate that release cytokines and chemokine

Question 22

What are the features of Sturge Weber Syndrome?

Answer 22

Port wine stain (naevus flammus) in the ophthalmic or maxillary divisions of the trigeminal nerve with a capillary vascular malformation intracranially

Can give rise to seizures

May also have hemisensory disturbance, hemiplegia, contralateral hemianopia and developmental delay

Head XR would show tramline calcifications

Question 23

Which enzyme is affected in Sjogren-Larsson syndrome?

Answer 23

Deficiency in the enzyme fatty aldehyde dehydrogenase

Question 24

What does TSC1 and TSC2 encode?

Answer 24

TSC1 encodes the protein hamartin
TSC2 encodes the protein tuberin

Both are implicated in tuberous sclerosis