Dermatitis

Question 1

what is the acute phase characterised by

Answer 1

erythema, oedema, vesicular/bullous lesions and exudates

Question 2

how are secondary infections heralded

Answer 2

golden crusting

Question 3

what is the chronic phase characterised by

Answer 3

scaling, dryness, elevated plaques and lichenification

Question 4

what effect can inflammation in the skin have on skin pigmentation

Answer 4

post inflammatory hypo/hyper pigmentation

Question 5

what type of hypersensitivty reaction is contact dermatitis

Answer 5

4

Question 6

name some common allergens for contact dermatitis

Answer 6

nickel, perfume, chrome (cement), latex

Question 7

time frame for contact dermatitis

Answer 7

48 hours

Question 8

contact dermatitis immunology

Answer 8

antigens penetrate epidermis and are picked up by Langerhans cells - T cells become sensitised. On subsequent exposure an allergic reaction occurs due to accumulation of sensitised T cells

Question 9

how can specific substances be tested for type 4 hypersensitivity

Answer 9

patch testing

Question 10

treatment for contact dermatitis

Answer 10

topical steroids and emollients

Question 11

what are the different strengths of topical steroids available

Answer 11

hydrocortisone 1% - mild

eumovate - moderate

betnovate - potent

dermovate - very potent

Question 12

irritant dermatitis

• mechanism
• when does it occur

Answer 12

non specific physical irritation - occurs when chemicals/physical agents damage the epidermis faster than the skin is able to repair the damage - no immune involvement

dermatitis occurs soon after exposure and severity varies with concentration and length of exposure

Question 14

how does atopic eczema typically present

• chronic

Answer 14

in childhood, initially with facial (cheeks) and subsequently flexural limb involvement

ill defined erythema and scaling

chronic changes: lichenification induces skin markings, excoriation caused by scratching, secondary infection

Question 15

what is atopic eczema often associated with

Answer 15

other atopic diseases eg asthma, food allergy

Question 16

atopic eczema history

Answer 16

tends to go back to childhood

Question 17

what does golden crusting indicate

Answer 17

transference of S Aureus by scratching

Question 18

treatment of eczema

Answer 18

emolients and topical steroids

avoid irritants including shower gels/soaps

treat infection

phototherapy

systemic immunosuppressants

Question 19

would you use UVA or UVB for phototherapy for eczema

Answer 19

UVB

Question 20

aetiology of atopic eczema

Answer 20

multiple genetic and environmental factors

Question 21

is there a genetic predisposition for eczema

Answer 21

yes common - filaggrin gene defects lead to impaired skin barrier function

Question 22

what does filaggrin mutation cause

Answer 22

ichythyosis vulgaris - skin doesnt shed its dead skin cells

Question 23

discoid eczema

• presentation
• aetiology

Answer 23

intensely pruritic coin shaped lesions commonly on limbs

cause is unknown, can be assoicated with S. Aureus and occur in atopic eczema

Question 24

eczema herpeticum

• history
• presentation

Answer 24

HSV infection that occurs at sites of skin damage eg burns, long term use of topical steroids

frequently there is a history of close contact with adult herpes labialis (cold sores)

small punched out looking lesions

Question 25

venous dermatitis - aetiology

Answer 25

occurs on lower legs of patients with venous insufficiency - due to fluid collecting in the tissues and activation of the immune response

Question 26

venous dermaitis presentation

Answer 26

venous eczema presents as itchy, red blistered and crusted plaques, or dry fissured and scaly plaques on one or both legs patients typically also have peripheral oedema and ulceration also: haemosiderin deposits and lipodermatosclerosis

Question 27

what can venous dermatitis lead to

Answer 27

2y eczema (spread to body) cellulitis contact allergy to treatments

Question 28

where does seborrhoeic dermatitis effect

Answer 28

areas of skin with lots of sebaceous glands eg scalp, eye brows, nasolabial folds, upper sternum and back there is often dandruff like scaling on the scalp

Question 29

describe the seborrhoeic dermatitis lesions

Answer 29

fine, greasy scales on erythematous background flat patches

Question 30

what is a differentiating feature between seborrhoeic dermatitis and psoriasis

Answer 30

SD is flat patches whereas psoriasis tends to be raised plaques

Question 31

pompholyx eczema - presentation - cause - clinical course

Answer 31

itching spongiotic vesicles on fingers, palms and soles unknown cause clinical course ranges from self limiting to chronic, severe and debilatating

Question 32

in which patients does pampholyx eczema tend to cocur

Answer 32

those with nickel allergy

Question 33

lichen simplex

Answer 33

localised area of lichenification produced by rubbing due to chronic localised itch primary itch may be due to eczema, psoriasis etc

Question 34

photosensitive eczema cause

Answer 34

can result from drugs taken internally or substances in contact with skin also plant material and sunlight obvs