dermatitis

Question 1

what does hyperkeratosis mean

Answer 1

increased thickness of keratin layer

Question 2

what does parakeratosis mean

Answer 2

persistence of nuclei in the keratin layer

Question 3

what does acanthosis mean

Answer 3

increased thickness of epidermis

Question 4

what does spongiosis mean

Answer 4

oedema between keratinocyctes

Question 5

what pathology is seen in biopsy of skin with eczema

Answer 5

• spongiosis

- inflammatory cell infiltrate: acute or chronic lympohoctes and/or neutrophils

Question 6

what are the acute and chronic phase features of dermatitis

Answer 6

acute phase

• papulovesicular
• erthematous (red) lesions
• oedema (spongiosis)
• ooze or scaling and crusting

chronic phase

• thickening (lichenification)
• elevated plaques
• increased scaling

Question 7

what is the immunopathology of contact allergic dermatitis

Answer 7

• langerhans cells in epidermis process antigen (immunogenicity)
• increased processed antigen is the presented to Th cells in dermis
• sensitised Th cells migrate into lymphatics and then to regional nodes where antigen presentation is amplified
• on subsequent antigen challenge specifically sensitised T cells proliferate and migrate to infiltrate skin

Question 8

how do you patch test

Answer 8

• batteries of allergen are place in small wells
• applied to back skin and left in place for 48 hours
• reactions checked after 96 hours

Question 9

what is irritant contact dermatitis

Answer 9

• non specific physical irritation rather than a specific allergic reaction
• may overlap with atopic dermatitis
• implication for occupation

Question 10

what are features of atopic eczema

Answer 10

• pruritus
• ill defined erythema and scaling
• generalised dry skin
• flexural distribution (varies with age)
• associated with other atopic diseases

chronic changes

• lichenification
• excoriation
• secondary infection (crusting indicates staph aureus)

Question 11

what is the UK diagnostic criteria for atopic eczema

Answer 11

itching plus 3 or more

• visible flexural rash
• history of flexural rash
• personal history or atopy (or fist degree relative is under 4 yr)
• generally dry skin
• onset before age 2

Question 12

treatment of eczema

Answer 12

1) plenty of emollients
2) avoid irritants including shower gel and soap
3) topical steroids
4) treat infections
5) phototherapy - mainly UVB
6) systemic immunosuppressants
7) biologic agents

Question 13

what is the gene that can cause eczema

Answer 13

fillagrin

Question 14

what is a evident feature of photosensitive eczema

Answer 14

cut off at collar