Dermatitis/Eczema

Question 1

Describe the acute phase of eczema?

Answer 1

Papulovesicular
Erythematous (red) lesions
Oedema (spongiosis)
Ooze or scaling and crusting

Question 2

Describe the chronic phase of eczema?

Answer 2

Thickening (lichenification)

Elevated plaques

Increased scaling

Question 3

What is the pathogenesis and histology of contact allergic dermatitis?

Answer 3

Delayed (IV) reaction

Spongiotic dermatitis

Question 4

What is the pathogenesis and histology of contact irritant dermatitis?

Answer 4

Trauma eg soap water

Spongiotic dermatitis

Question 5

What is the pathogenesis and histology of atopic dermatitis?

Answer 5

Genetic and environmental factors resulting in inflammation

Spongiotic dermatitis

Question 6

What is the pathogenesis and histology of drug-allergic dermatitis?

Answer 6

Type 1 or 4 reaction

Spongiotic dermatitis and eosinophils

Question 7

What is the pathogenesis and histology of photo-induced or photosensitive dermatitis?

Answer 7

Reaction to UV light

Spongiotic dermatitis

Question 8

What is the pathogenesis and histology of lichen simplex dermatitis?

Answer 8

Physical trauma to skin- scratching

Spongiotic dermatitis and external trauma

Question 9

What is the pathogenesis and histology of stasis dermatitis?

Answer 9

Physical trauma to skin-hydrostatic pressure

Spongiotic dermatitis and extravasation of RBCs

Question 10

Describe the immunopathology of contact allergic dermatitis?

Answer 10

Langerhans cells in epidermis processes antigen (increased immunogenicity)

Processed antigen is then 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 T cells proliferate and migrate to and infiltrate skin

Question 11

How can specific causes of contact dermatitis be identified?

Answer 11

Patch testing

Question 12

What is irritant (contact) dermatitis

Answer 12

Non specific physical irritation rather than a specific allergic reaction

Question 13

What is the distribution of atopic eczema?

Answer 13

Flexural distribution

Question 14

What is the general skin like in atopic eczema?

Answer 14

Dry

Question 15

What secondary infections are common in atopic eczema?

Answer 15

Staph aureus

Question 16

What is an eczema infection that is important to recognise early?

Answer 16

Eczema herpeticum
caused by herpes simplex virus

Will see monomorphic punched out lesions

Question 17

What are the UK diagnostic criteria for atopic eczema?

Answer 17

Itching plus 3 or more;

• visible flexural rash
• history of flexural rash
• personal history of atopy
• generally dry skin
• onset before age 2

Question 18

Describe the treatment of eczema?

Answer 18

1) plenty of emolients
2) avoid irritants
3) topical steroids
4) treat infections
5) phototherapy- mainly UVB
6) Phototherapy- mainly UVB
7) biologic agents

Question 19

What is the most important gene in eczema?

Answer 19

Filaggrin

Question 20

discoid eczema patients are often …

Answer 20

Atopic

Question 21

What is seen in photosensitive eczema?

Answer 21

Chronic actinic dermatitis

Patients are often atopic

See cut off at exposed areas vs covered

Question 22

What is seen in pompholyx eczema?

Answer 22

Spongiotic vessels