Dermatitis & Atopic Eczema

Question 1

what is hyperkeratosis?

Answer 1

increased thickness of keratin layer

Question 2

what is parakeratosis?

Answer 2

persistence of nuclei in the keratin layer

Question 3

what is acanthosis?

Answer 3

increased thickness of epidermis

Question 4

what is papillomatosis?

Answer 4

irregular epithelial thickening

Question 5

what is spongiosis?

Answer 5

oedema between keratinocytes

Question 6

describe inflammatory cell infiltrate

Answer 6

can be acute or chronic infiltration of lymphocytes &/or neutrophils

Question 7

what is dermatitis characterised by?

Answer 7

• itching
• usually ill defined
• erythematous
• scaly

Question 8

what happens in the acute phase of eczema?

Answer 8

papulovesicular
erythematous lesions
spongiosis
scaling & crusting

Question 9

what happens in the chronic phase of eczema?

Answer 9

lichenification
elevated plaques
increased scaling

Question 10

describe the differences between the reactions in contact allergic and contact irritant dermatitis?

Answer 10

contact allergic = specific reaction

contact irritant = non-specific reaction

Question 11

name some common contact allergic dermatitis triggers

Answer 11

nickel

substances in gloves e.g. latex

Question 12

what are the pathological features of contact allergic dermatitis?

Answer 12

spongiosis

inflammatory cell infiltrate

Question 13

how can specific substances causing contact dermatitis be identified?

Answer 13

through patch testing

Question 14

what are the disadvantages of patch testing?

Answer 14

can’t shower/go to gym & can be uncomfortable to sit/sleep for 48 hours

Question 15

when are patch tests checked & why?

Answer 15

taken off after 48 hours

checked after 96 hours as looking for delayed hypersensitivity

Question 16

how is irritant (contact) dermatitis different to contact allergic dermatitis?

Answer 16

it’s a non-specific physical irritation rather than a specific allergic reaction

Question 17

if a patient is atopic, are they more likely to have irritant (contact) dermatitis or contact allergic dermatitis?

Answer 17

contact allergic dermatitis

Question 18

what are some common irritant dermatitis triggers?

Answer 18

• mechanical oils
• soap
• some metals
• licking lips (saliva)

Question 19

what is nappy rash?

Answer 19

a non-specific irritant contact dermatitis in response to urine/faeces

Question 20

what happens in flexures in atopic eczema?

Answer 20

is worse in flexures

Question 21

what is generalised dry skin a manifestation of?

Answer 21

an abnormal skin barrier which lets water leak out & becomes dry

Question 22

what chronic changes occur to the skin in atopic eczema?

Answer 22

lichenification
excoriation (crusting)
secondary infection

Question 23

what does crusting of eczema indicate?

Answer 23

Staph. aureus infection

Question 24

how is staph. aureus introduced into the eczema?

Answer 24

through scratching

Question 25

what do monomorphic punched-out lesions leading away from eczema mean?

Answer 25

eczema herpeticum (herpes simplex virus)

Question 26

what is the diagnostic criteria for atopic eczema?

Answer 26

itching plus 3 or more of:

• visible flexural rash (cheeks & extensor surfaces in infants)
• history of flexural rash
• personal history of atopy
• generally dry skin
• onset before 2 yrs old

Question 27

how do you treat eczema?

Answer 27

• plenty of emollients
• avoid irritants
• topical steroids
• treat infection
• phototherapy (mainly UVB)
• systemic immunosuppressants

Question 28

what causes atopic eczema?

Answer 28

multiple genetic & environmental factors

Question 29

what is the most important gene in atopic eczema?

Answer 29

filaggrin

Question 30

how can you recognise photosensitive eczema?

Answer 30

cut off at collar & no eczema in areas protected from sun (e.g. behind ears)

Question 31

what is stasis eczema secondary to?

Answer 31

• hydrostatic pressure
• oedema
• red cell extravasation

Question 32

what is cradle cap?

Answer 32

seborrhoeic dermatitis

Question 33

what is lichen simplex caused by?

Answer 33

patient scratching and creating the eczema