Textbook notes

Question 1

A non-infective inflammatory disorder following a spongiotic reaction pattern - oedema fluid separates individual keratinocytes ?

Answer 1

acute eczema

Question 2

What constitutes a vesicle in acute eczema?

Answer 2

intra-epidermal aggregates of oedema fluid + lymphocytes = vesicles

Question 3

What skin change is likely to occur in chronic eczema (esp. if there has been repeated rubbing & scratching)?

Answer 3

lichenification

Question 4

List some microscopic features of eczematous dermatitis.

Answer 4

upper dermal perivascular lymphocytic infiltrate
spongiosis
vesicles
chronicity leading to acanthosis, surface scale, and dermal fibrosis
subacute lesions show a combination of acute and chronic features

Question 5

What is Filaggrin?

Answer 5

a protein that promotes the aggregation of keratin filaments into granules go keratohyalin within the granular layer
essential for barrier function

Question 6

2 examples of exogenous eczema?

Answer 6

primary irritant dermatitis

allergic contact dermatitis

Question 7

Describe the reaction and cell process involved in allergic contact dermatitis.

Answer 7

Type IV hypersensitivity (delayed)
Antigen processed by Langerhans cells - presented to T cells - re-exposure to antigen provokes helper T cells to release inflammatory mediators.

Question 8

Photo-allergic dermatitis occurs in response to what?

Answer 8

occurs on sun-exposed sites in response to topically applied/ingested photo-sensitising agent (often a drug)

Question 9

The presence of which cells within an inflammatory dermatitis often reflects drug-based aetiology?

Answer 9

eosinophils

Question 10

Increased epidermal turnover is characteristic of which relapsing and remitting skin disorder?

Answer 10

psoriasis

Question 11

Skin eruption in young adult - papules of 5-15mm diameter in rain-drop shape?

Answer 11

eruptive guttate psoriasis

Question 12

What is the most common type of psoriasis?

Answer 12

psoriasis vulgaris aka. chronic plaque psoriasis

Question 13

What is Auspitz’ sign?

Answer 13

if a few scales are scraped off in psoriasis -> multiple small bleeding points on the exposed surface

Question 14

What is Koebner’s phenomenon?

Answer 14

Psoriatic plaque development triggered by trauma

Question 15

List some microscopic features of psoriasis.

Answer 15

Hyperkeratosis
Parakeratosis
rete ridge elongation 
supra-papillary plate thinning 
frequent supra-basal mitoses
dilated dermal capillaries
munro's micro abscesses

Question 16

What are munro’s micro abscesses?

Answer 16

collections of neutrophils in stratum corneum

Question 17

How fast is keratinocyte turnover in psoriasis?

Answer 17

3-7 days for psoriatic keratinocytes to travel to epidermis before shedding
(28 in unaffected patients)

Question 18

Skin-specific T lymphocytes has been identified for producing which inflammatory markers in psoriatic lesions?

Answer 18

IL-22 and interferon gamma

Question 19

What are some topical therapies for psoriasis?

Answer 19

Vitamin D analogues 
Coal tar
Dithranol 
Steroid ointments
Emollients

Question 20

Non-topical therapies for psoriasis?

Answer 20

narrowband UVB and PUVA
methotrexate
biological agents

Question 21

Itchy, scaly and violaceous papules appeared on skin of 30 y/o on both wrists and hands.

Answer 21

Lichen planus

Question 22

Which layer of epidermis is damaged in lichen planus?

Answer 22

focal basal layer liquefaction

Question 23

Persistent and chronically ulcerated oral lichen planus is associated with an increased risk of which cancer?

Answer 23

SCC

Question 24

What is lichen planopilaris?

Answer 24

when lichen planus predominates the hair follicle epithelium -> destruction of follicular units & alopecia

Question 25

List microscopic features of lichen planus.

Answer 25

Irregular, 'saw-toothed', acanthosis with hyperkeratosis Dense band-like infiltrate of lymphocytes & histiocytes at DEJ Liquefaction degeneration of the basal layer Cytoid bodies in upper dermis Melanin pigment incontinence (released from damaged basal cells into dermis)

Question 26

3 other examples of lichenoid dermatoses.

Answer 26

lupus erythematous erythema multiforme GVHD

Question 27

Which lichenoid reaction pattern is associated with antinuclear antibodies and anti-DNA antibodies?

Answer 27

lupus erythematous (LE)

Question 28

Name and describe the most common variant of LE.

Answer 28

Diffuse Lupus Erythematous (DLE) localised condition - scaly red patches over nose & cheeks often exacerbated by sunlight lesions heal slowly with scarring; if scalp involved -> permanent alopecia

Question 29

Microscopic features of DLE?

Answer 29

epidermal atrophy + hyperkeratosis follicular plugging basement membrane thickens (with chronicity) granular basement membrane deposition of IgG, IgM, or C3 on direct immunofluorescence

Question 30

What is the presentation of subacute LE?

Answer 30

a recurring photosensitive rash on face, trunk, & upper limbs can be drug induced (e.g. PPI) visceral involvement rare