Allergy: Eczema

Question 1

What percentage of children with atopic dermatitis develop asthma or allergic rhinitis later in life?

Answer 1

Up to 80%

Question 2

What is the prevalence of atopic dermatitis in children in the UK?

Answer 2

Approximately 20%

Question 3

Do many affected children have a FH of allergy?

Answer 3

Yes

Question 4

Are IgE antibodies to common allergens usually present?

Answer 4

Yes

Question 5

What gene mutations have been identified as the key genetic risk factor for eczema development?

Answer 5

Filaggrin mutation - impairment of skin barrier function. This leads to cutaneous sensitisation to inhalant and food allergens
(Filaggrin mutation predisposes to food allergy, asthma, hay fever as well as eczema)

Question 6

What percentage of young infants with severe eczema have an IgE mediated food allergy?

Answer 6

40% - in particular egg allergy

Question 7

When does the onset of atopic eczema generally occur?

Answer 7

First year of life

Uncommon in first 2 months (unlike infantile seborrhoeic dermatitis)

Question 8

What are atopic disorders?

Answer 8

Atopic dermatitis
Asthma
Allergic rhinitis (hay fever)

Question 9

What percentage resolves by 12 years of age?

Answer 9

50% and 75% by 16

Question 10

What may delay the onset of atopic dermatitis in predisposed children?

Answer 10

Exclusive breastfeeding

Question 11

How is it diagnosed?

Answer 11

Clinically
If unusually severe, atypical, associated with unusual infections or faltering growth - an immune deficiency disorder should be excluded

Question 12

What is the main symptom at all ages?

Answer 12

Pruritus

Question 13

What does the distribution of atopic eczema change with?

Answer 13

Age

Question 14

Which areas of the body are typically affected in infants?

Answer 14

Face
Scalp
Trunk

Question 15

Which areas of the body are typically affected in older children?

Answer 15

Skin flexures - cubital and popliteal fossae

Frictional areas - neck, wrists, ankles

Question 16

Describe the appearance

Answer 16

Itchy, dry patches of papules and vesicles on an erythematous base.

Question 17

Scratching can lead to…

Answer 17

Excoriation areas

Question 18

Prolonged scratching and rubbing of the skin can lead to..

Answer 18

Lichenification

Question 19

Are flare ups common?

Answer 19

Yes and often for no obvious reason

Question 20

Describe mild atopic dermatitis

Answer 20

Areas of dry skin
Infrequent itching
With/without small areas of redness

Little impact on everyday activities, sleep, psychosocial well-being

Question 21

Describe moderate disease

Answer 21

Areas of dry skin
Frequent itching
Erythematous areas
With or without excoriation and localised skin thickening

Moderate impact on everyday activities, frequently disturbed sleep

Question 22

Describe severe disease

Answer 22

Widespread areas of dry skin
Incessant itching
Erythema
With or without excoriation, extensive thickening, bleeding, oozing, cracking and alteration of pigmentation
Severe limitation of everyday activities and psychosocial functioning, nightly sleep loss

Question 23

What complications can occur?

Answer 23

Bacterial infection - staphylococcus and streptococcus species 
Viral infections - herpes simplex 
Ingestion of an allergen e.g egg
Contact with an irritant or allergen
Environment: heat, humidity 
Change or reduction in medication
Psychological stress

Question 24

What bacteria thrives on atopic skin?

Answer 24

Staphylococcus aureus

Question 25

Why is an herpes simplex infection potentially very serious?

Answer 25

Can spread rapidly on atopic skin Extensive vesicular reaction = eczema herpeticum

Question 26

What is common on examination in active eczema?

Answer 26

Regional lymphadenopathy

Question 27

In terms of management, what options are available?

Answer 27

``` Avoiding irritants and precipitate Emollients Topical corticosteroids- mild and moderate Immunomodulators Occlusive bandages Antibiotics, antivirals, antihistamines Dietary elimination Phototherapy Systemic therapy Psychosocial support ```

Question 28

What irritants and precipitants should be avoided?

Answer 28

Soap Biological detergents Clothing next to skin should be of pure cotton (avoid nylon and pure woollen garments) Cut nails Mittens at night Avoid allergen if one has been identified e.g cow’s milk

Question 29

What is the mainstay of management?

Answer 29

Emollients - moisturise and soften skin

Question 30

How should emollients be applied?

Answer 30

Liberally 2 or more times per day After a bath They include ointments - preferable to creams when skin very dry

Question 31

What is an example of a mildly potent corticosteroid?

Answer 31

1% hydrocortisone- applied for eczematous area once/twice per day

Question 32

Moderately potent corticosteroids play a role in the management of...

Answer 32

Acute exacerbations | Should be kept to a minimum

Question 33

Moderately potent topical corticosteroids should be avoided on...

Answer 33

The face

Question 34

What can be used in children over 2 if eczema NOT controlled by topical corticosteroids or serious risk of adverse effects from further topical steroids (e.g irreversible skin atrophy)?

Answer 34

Short term use of tacrolimus ointment or pimecrolimus cream (immunomodulators)

Question 35

What is the role of occlusive bandages?

Answer 35

Helpful over limbs when scratching and lichenification are a problem. May be impregnated with zinc paste or zinc and tar paste Worn overnight for 2-3 days at a time until skin improved Widespread itching in young children: short term use of wet stockinette wraps - dilute topical steroids mixed with emollient

Question 36

What can be used for itch suppression?

Answer 36

Antihistamines but should not be used routinely in children Offer 1 month trial if moderate to severe itching OR 7-14 day trial to children over 6 months if acute flare if sleep disturbed Non sedating e.g cetirazine

Question 37

How should mild atopic eczema be managed?

Answer 37

Emollients | Mild potency topical corticosteroids

Question 38

How should moderate atopic eczema be managed?

Answer 38

Emollients Moderate potency topical corticosteroids Topical calcineurin inhibitors e.g tacrolimus Bandages

Question 39

How should severe atopic eczema be managed?

Answer 39

``` Emollients Potent topical corticosteroids Topical calcineurin inhibitors Bandages Phototherapy Systemic therapy ```

Question 40

What antibiotic should be used in first line treatment for widespread bacterial infection ?

Answer 40

Flucloxacillin for 1 to 2 weeks according to clinical response

Question 41

When should food allergy be considered?

Answer 41

Child reacts consistently to food In infants and young children with moderate or severe atopic eczema, particularly if associated with gut dysmotility or faltering growth

Question 42

If eczema herpeticum is suspected, how should the child be managed?

Answer 42

Oral aciclovir started immediately even if localised infection