Atopic dermatitis

Question 1

Define atopic dermatitis

Answer 1

Inflammatory skin condition characterised by dry, pruritic skin with a chronic relapsing course
Typically an episodic disease with flares that may occur up to 2-3x a month

Question 2

What are the types of dermatitis

Answer 2

Atopic: type I/IV IgE-mediated hypersensitivity
Contact: type IV delayed HS reaction after allergen/irritant exposure
Discoid: coin-shaped plaques in middle aged/elderly pts
Dishydrotic (pompholyx), itchy/painful blisters on palms/plantars
Herpeticum: HSV-1 infection (medical emergency)
Seborrhoeic (Cradle cap): yellow/greasy scaly rash of the scalp, paranasal areas, eyebrows

Question 3

What is the aetiology of atopic dermatitis

Answer 3

Combination of genetic susceptibility and environmental factors
Defect in skin’s barrier function
Filaggrin mutation (stratum corneum has lower levels of natural moisturising factor)

Type I hypersensitivity: Impaired epidermal barrier function due to intrinsic structural and functional skin abnormalities e.g. filaggrin mutation
Type IV hypersensitivity: Immune function disorder in which Langerhans cells, T cells and immune effector cells modulate an inflammatory response to environmental factors

Question 4

What are the risk factors for atopic dermatitis

Answer 4

Age <5 years
Family history
Allergic rhinitis, hay fever
Asthma
Food allergies
Active and passive exposure to smoke
Urban areas
Smaller families
High socio-economic classes

Question 5

What are the symptoms of atopic dermatitis

Answer 5

Pruritus (may be seasonal, better in the summer)
Xerosis (dry skin)
Erythema
Scaling

Involving:
Infants: cheeks, forehead, scalp, extensor surfaces
Older children: Extensors of limbs
Children: flexures, particularly the wrists, ankles, antecubital and popliteal fossa
Chronic: neck, upper back, arms, hands and feet

Question 6

What are the differentials for atopic dermatitis

Answer 6

Psoriasis
Allergic contact dermatitis
Seborrheic dermatitis
Fungal infection
Scabies/other infestation
Food allergy

Question 7

lWhat are the signs of eczema on examination

Answer 7

Papules and vesicles (weepy/exudative)
- Extensors (infants) or flexors (children/adults)
Pigmented skin: brown, grey, purple bumps
Xerosis
Erythema
Keratosis pilaris (follicular hyperkeratotic papules on the extensor surfaces)
Excoriations
Lichenification (thickening of skin due to repeated scratching)
Hypopigmentation or hyperppigemntation
Nails: pitting and ridging

Question 8

What investigations should be done for atopic dermatitis

Answer 8

Clinical diagnosis
Assess severity:
± Patient-Oriented Eczema Measure (POEM)
± Infants’ dermatitis quality of life index (IDQoL)
± Children’s dermatology Life Quality Index (CDLQI)

Bloods: IgE raised
Other: skin biopsy (eczema from contact dermatitis and psoriasis), skin prick testing (food allergies), patch testing (contact dermatitis)

Question 9

What classifies mild eczema

Answer 9

Areas of dry skin with infrequent itching + small areas of redness
Little impact on everyday activities, sleep and psychosocial wellbeing

Question 10

What classifies moderate eczema

Answer 10

Areas of dry skin
Frequent itching
Areas of redness ± excoriation and localised skin thickening

Moderate impact on everyday activities and psychosocial wellbeing
Frequently disturbed sleep

Question 11

What classifies severe eczema

Answer 11

Widespread areas of dry skin
Incessant itching
Redness ± excoriation, extensive skin thickening, bleeding, oozing, cracking, alteration of pigmentation

Severe limitation of everyday activities and psychosocial functioning
Nightly loss of sleep

Question 12

What is the management for mild eczema

Answer 12

Emollients
Mild potency topical corticosteroids
Consider referral to clinical psychologist

Question 13

What is the management for moderate eczema

Answer 13

Emollients
Moderate potency topical corticosteroids (Step-down approach)
Topical calcineurin inhibitors
Bandages
Consider referral to clinical psychologist

Question 14

What is the management for severe eczema

Answer 14

Emollients
Potent topical corticosteroids
Phototherapy
Topical calcineurin inhibitors
Bandages
Consider referral to clinical psychologist

Question 15

What is the management for infected eczema

Answer 15

Skin and swab culture
- Oral flucloxacillin
- Erythromycinc/clarithromycin alternative

Question 16

What emollients are used for atopic dermatitis and how should they be used

Answer 16

50/50 (greasy), dermol (contains chlorhexidine), e45

Apply to whole body and wait 30 minutes before applying steroid creams
Used for moisturising, washing and bathing
Pump products = reduced infection risk
Apply with the finger tips (FTUs) / 500mg
- 1 FTU = palm of hand, elbows, or knees
Can be used with bandages for chronic lichenified skin

Question 17

What is the difference between a cream and ointment

Answer 17

Cream = some water (thin, contains preservatives)
Ointment = no water (thick, no preservative)

Question 18

What is the steroid ladder for atopic dermatitis treatment

Answer 18

From least to most potent
Hydrocortisone
Eumovate/clobetasone
Betnovate/betamethasone
Elocon/mometasone
Dermovate/clobetasol

Note: Apply sparingly to affected areas only

Question 19

Give examples of topical calcineurin inhibitors and how should they be used

Answer 19

Tacrolimus, pimecrolimus
Topical to active eczema areas
Apply as a thin layer to affected areas, including broken skin, up to twice daily
Do not use on infected skin
Do NOT use under occlusive bandages

Question 20

Give examples of antihistamines that can be used for atopic dermatitis

Answer 20

Severe itching/urticaria → 1 month trial of non-sedating antihistamine e.g. fexofenadine, cetirizine
Acute flare-up with sleep disturbance → 7-14 days trial of sedating antihistamine e.g. promethazine

Question 21

When should you refer for atopic dermatitis

Answer 21

⚑ Eczema herpeticum → immediate + empirical treatment with oral/IV Abx and oral/IV acyclovir (due to similar presentation to impetigo)

Severe atopic eczema not responding to optimum therapy within 1 week → Urgent (<2 weeks)
Treatment to bacterially infected eczema has failed → Urgent (<2 weeks)
Non-urgent (>2 weeks)
- Diagnosis uncertain
- Atopic eczema on face not responding
- Contact allergic dermatitis suspected
- Causing significant social and psychological problems
- Severe recurrent infections

Question 22

What are the complications of atopic dermatitis

Answer 22

Secondary bacterial infection
Impetigo
Secondary viral infection e.g. molluscum contagiosum
Eczema herpeticum
Psychosocial problems: distress, depression, behavioural problems, poor sleep-esteem and confidence, sleep disturbance

Question 23

Describe eczema herpeticum

Answer 23

Widespread lesions that may coalesce into large, denuded, bleeding areas that can extend over the entire body
Punched out lesions (circular, depressed, ulcerated)
rapidly progressing painful rash, fever, lymphadenopathy and malaise

Question 24

What is the management for eczema herpeticum

Answer 24

1. Admit - medical emergency
2. Oral aciclovir (if unwell → IV aciclovir)
   - Around the eyes → same day referral to ophthalmologist
3. Safety net:
   - Rapidly worsening eczema
   - Clustered blisters
   - Punched-out erosions

Question 25

What is the prognosis for atopic dermatitis

Answer 25

Typically an episodic disease of flares and remissions
May gradually improve as they grow older:
- 65% clearance by the age of 7
- 74% clearance by the age of 16