Eczema

Question 1

Give the definition of atopic eczema

Answer 1

Atopic dermatitis caused by inflammation in flexural areas.

Question 2

Describe the distribution of atopic eczema

Answer 2

Usually has a symetrical distribution:
Flexures
Neck
Eyelids
Face
Hands
Feet

Question 3

What is the key gene associated with eczema?

Answer 3

Filaggrin gene

Question 4

Describe the pathology of eczema

Answer 4

• Spongiosis = epidermis cells swell and split apart due to oedema
• Acanthosis = thickening of epidermis
• Inflammation = due to lymphohistiocytic infiltration

Question 5

Describe the appearance and distrubution of contact dermatitis

Answer 5

Redness, vesicles/papules, crusting/scaling
Areas exposed to irritant/allergen
Often hands/nails and nappy rash

Question 6

Describe the appearance of lichen simplex eczema

Answer 6

Localised demarcated plaque

Scaling, excoriations, lichenification

Question 7

Describe the distrubution of lichen simplex eczema

Answer 7

Common on calves, elbows, shins, behind the neck, and genitals

Question 8

What is the main symptom of lichen simplex eczema?

Answer 8

severe itch

Question 9

Describe the appearance and distrubution of seborrhoeic eczema

Answer 9

Red, inflamed skin with greasy yellow scales. May also have salmon-pink patches/plaques.
Affects “sweaty areas” e.g. face, scalp, armpits, groin, chest

Question 10

Which type of eczema is usually painless and non-itchy?

Answer 10

Seborrhoeic eczema (children are not distressed - “happy baby”)

Question 11

Describe the appearance and distribution of discoid eczema

Answer 11

Circular erythematous plaques
Symmetrical distrubution
Often on extremities, especially the legs, but can occur anywhere

Question 12

List the types of internal/endogenous eczema

Answer 12

P. DAVIES:

Pompholyx
Discoid
Atopic
Venus
Infected
Eczema herpeticum
Seborrhoeic

Question 13

Which type of eczema may sting/burn and is worse at night?

Answer 13

Discoid eczema

Question 14

Which type of eczema is mainly distrubuted on the soles of the feet and palms of the hands?

Answer 14

Pompholyx eczema

Question 15

Describe the appearance of pompholyx eczema

Answer 15

Vesicular eruptions (small, fluid-filled lesions)

Question 16

Which type of eczema commonly affects the shins of elderly patients? Describe the appearance of this type of eczema

Answer 16

Asteatotic eczema

Very dry skin

Question 17

Describe the appearance of venous eczema

Answer 17

Poorly defined scaling and erythema. Pigment changes e.g. browning. Skin can blister and weep. Patients also often have varicose veins.

Question 18

Describe the distribution of venous eczema

Answer 18

Bilateral ankles and lower legs

Question 19

What is eczema herpeticum?

Answer 19

Disseminated infection of herpes simplex virus. It is often a complication of atopic eczema.

Question 20

Describe the appearance of eczea herpeticum

Answer 20

Itchy clusters of blisters and erosions. Distribution depends on the initial eczema distrubution.

Question 21

What other symptoms may be associated with eczema herpeticum?

Answer 21

Fever

Swollen lymph nodes

Question 22

Suggest some potential causes/triggers of atopic eczema

Answer 22

Irritants, infections, contact allergens, inhaled allergens
Extremes of temperature and humidity
Genetic factors (filaggrin gene)
Stress
Hormonal factors

Question 23

Describe the aetiology of allergic contact dermatitis and suggest some potential allergens

Answer 23

Type 4 hypersensitivity reaction
T-cell mediated
Cosmetics, metals (e.g. cobalt, nickel), topical drugs, textiles, plants

Question 24

Describe the aetiology of irritant contact dermatitis

Answer 24

Friction
Environmental: cold, over-exposure to water
Chemical: acids, alkalies, detergents, solvents

Question 25

Which type of eczema begins as eczema of another cause but is exacerbated by an itch-scratch cycle? How can this be managed?

Answer 25

Lichen simplex eczema | Apply dressings to prevent scratching

Question 26

What causes seborrhoeic eczema?

Answer 26

In adults: Inflammatory reaction to Malassezia yeast | In newborns: Sometimes caused by yeast, other times is caused by over-activity of the sebaceous glands

Question 27

Which fungi is linked to seborrhoeic eczema?

Answer 27

Malassezia yeast

Question 28

How is seborrhoeic eczema treated?

Answer 28

Topical anti-yeast shampoo e.g. ketoconazole | Often self-limiting in infants so may not need treatment

Question 29

What underlying pathology should be considered in cases of seborrhoeic eczema that are severe, prolonged and/or have no family history?

Answer 29

Underlying HIV infection; consider HIV testing

Question 30

Describe the aetiology of discoid eczema

Answer 30

Usually idiopathic/unknown May develop at site of trauma or irritation N.B. infection is usually occurs secondary to the eczema rather than being a cause.

Question 31

Describe the aetiology of pompholyx eczema

Answer 31

``` Unknown but is associated with: - Stress - Allergy - Genetics - HIV Usually self-limiting but symptomatic treatment of itch is often required ```

Question 32

What can exacerbate asteatotic eczema?

Answer 32

Climate (heat) | Excessive washing/soaps

Question 33

How is asteatotic eczema managed?

Answer 33

Does not require steroids | Apply lots of emollient

Question 34

Describe the aetiology of venous eczema. How can this be managed?

Answer 34

Increased venous pressure causes oedema. Compression stockings should be worn to improve venous circulation. Also important to manage fluids as the skin can weep, leading to dehydration.

Question 35

What underlying pathology is associated with an increased risk of eczema herpeticum?

Answer 35

HIV infection

Question 36

Describe the general management of eczema

Answer 36

``` Emollient/moisturisers - ointment, cream, lotion Topical steroids - hydrocortisone Severe eczema may be treated with UV light and/or immunosuppression. ?anti-histamines ?calcineurin inhibitors ```

Question 37

Describe the role of epidermal barrier dysfunction in the pathophysiology of eczema

Answer 37

Two-way barrier defect: - water gets out - irritants/allergens get in

Question 38

Describe the general acute changes seen in eczema

Answer 38

– Pruritus, Erythema, Scale, Papules, Vesicles | – Exudate, crusting, excoriation

Question 39

Describe the general chronic changes seen in eczema

Answer 39

Lichenification, Plaques, Fissuring

Question 40

How is allergic contact dermatitis investigated?

Answer 40

Patch Testing - can take 48-72 hours to develop reaction (type 4 hypersensitivity): - potential allergens applied (no needles involved!) - baseline/standard series of around 40 allergens isapplied to all patients. Some patients may require additional series (e.g. occupation-dependant). * Apply Monday * Remove Wednesday * Re-assess Friday