Dermatitis/eczema

Question 1

What is hyperkeratosis?

Answer 1

Increased thickness of the 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 the epidermis

Question 4

What is papillomatosis?

Answer 4

Irregular epithelial thickening

Question 5

What is papillomatosis characteristic of?

Answer 5

Warts (mostly viral)

Question 6

What is spongiosis?

Answer 6

Oedema between kertinocytes

Question 7

What histological features are typical of eczema?

Answer 7

Spongiosis and inflammatory cell infiltrate (acute/chronic, lymphocytes &/or neutrophils)

Question 8

General dermatitis/eczema can be defined as what?

Answer 8

Skin lesions with similar clinical and pathological features but differing pathogenic mechanisms

Question 9

What is the acute phase of dermatitis characterised by?

Answer 9

Papulovesicular rash, erythematous lesions, oedema, ooze, scaling and crusting

Question 10

What is chronic dermatitis characterised by?

Answer 10

Lichenification, raised plauques, increased scaling

Question 11

What is the one universal feature of dermatitis (acute or chronic)?

Answer 11

Itching

Question 12

How might dermatitis present generally?

Answer 12

Itchy, ill-defined, erythematous, scaly skin lesions

Question 13

List all the different types of eczema and their corresponding pathogenesis

Answer 13

Contact allergic - type 4 hypersensitivity
Contact irritant - trauma
Atopic - genetic & environmental factors
Drug related - type 1 or type 4 hypersensitivity
Photosensitive - reaction to UV light
Lichen simplex - physical trauma (scratching)
Stasis dermatitis - physical trauma (hydrostatic pressure)

Question 14

What are the common contact allergies?

Answer 14

Nickel, chemicals, topical therapies, plants

Question 15

Describe the immunopathology of contact allergy?

Answer 15

Epidermal langerhans cells process antigen > processed antigen is presented to Th cells in dermis > sensitised Th cells migrate to lymphatics and regional nodes > antigen presentation is amplified > re-exposure to antigen causes sensitised T cells to proliferate, migrate and infiltrate skin > dermatitis

Question 16

How can the allergens causing contact allergy be identified?

Answer 16

Patch testing

Question 17

What is the time frame for patch testing?

Answer 17

Allergen wells are left on the skin for 48 hours and checked for reaction after 96 hours

Question 18

What is contact irritant dermatits?

Answer 18

Non-specific physical irritation to some external factor (NOT an immune reaction)

Question 19

Irritant contact dermatitis may force some patients to change jobs. T/F

Answer 19

True

Question 20

How is irritant contact dermatitis usually managed?

Answer 20

Avoidance

Question 21

The incidence for atopic eczema in children is relatively low. Tends to present in early adulthood. T/F

Answer 21

False - tends to present in childhood and disappear by adulthood

Question 22

How may pruritus be a particular problem in atopic eczema?

Answer 22

Itching causes sleep disturbance which may result in neurocognitive impairment. In young children this tends to put strain on the whole family

Question 23

The itch-scratch cycle in eczema causes amplified itching. T/F

Answer 23

True

Question 24

How does atopic eczema present?

Answer 24

• itchy, ill-defined erythematous scaly plaques
• generalised skin dryness
• flexural distribution
• facial distribution in young children
• associated atopy

Question 25

Where is a common and often overlooked site for the occurrence of eczema in children?

Answer 25

Under/behind the earlobe

Question 26

What are the chronic changes associated with atopic eczema?

Answer 26

Lichenification, excoriation, secondary infection

Question 27

What main feature would indicate typical infected eczema?

Answer 27

Crusting (most commonly s.aureus)

Question 28

How does eczema herpeticum present?

Answer 28

Monomorphic punched out lesions

Question 29

What is the diagnostic criteria for atopic eczema?

Answer 29

Itching AND 3 or more of: - visible flexural rash* - history of flexural rash* - personal history of atopy (or first degree relative if

Question 30

How is eczema treated?

Answer 30

- EMOLLIENTS - avoidance of irritants (soaps) - topical steroids - infection treatment if present - phototherapy (UVB mostly) - systemic immunosuppressants

Question 31

What is the most important genetic factor in the development of atopic eczema?

Answer 31

Mutation in the filaggrin gene

Question 32

What is discoid eczema?

Answer 32

Disk shaped distribution of eczema (pattern of atopic eczema)

Question 33

How can discoid eczema and psoriasis be differentiated?

Answer 33

Discoid will be a patch while psoriasis will be a plaque

Question 34

What is chronic actinic dermatitis? What characteristic feature does it usually show?

Answer 34

Photosensitivity dermatitis. Dermatitis cuts off at the collars of shirts/where the skin is covered

Question 35

Are patients with chronic actinic dermatitis also atopic?

Answer 35

Sometimes (often)

Question 36

How does stasis eczema present?

Answer 36

In areas of high hydrostatic pressure (i.e varicose veins), oedematous and with red cell extravasation (giving erythema)

Question 37

What is seborrhoeic dermatitis?

Answer 37

Dermatitis which particularly effects the areas of the skin with a high density of sebaceous glands. In infants - cradle cap. In adolescents/adults - scalp and nasolabial fold

Question 38

What is pompholyx eczema? How does it present?

Answer 38

Acute eczema. Spongiotic vesicles

Question 39

What is lichen simplex?

Answer 39

Eczema with no specific disease but caused due to continued scratching (itch-scratch cycle)