Atopic dermatitis & eczema (D) Flashcards

1
Q

Define eczema.

A

Inflammatory skin condition characterised by dry, pruritic skin with a chronic relapsing course

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2
Q

What demographic does eczema typically affect?

A

M=F, usually presents in childhood (most commonly diagnosed before 5 years, affects 10-20% of children)

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3
Q

What do patients with eczema usually have a history of?

A

Personal or family history of atopic diseases e.g. asthma or allergic rhinitis

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4
Q

How can eczema be described? (2 types)

A
  • acute (flare-up of symptoms)
  • chronic (when the patient develops signs of chronic inflammation e.g. lichenification)
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5
Q

What are the typical features of eczema? (4)

A
  • erythema
  • scaling
  • vesicles
  • lichenification in skin flexures
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6
Q

What are the three types of eczema?

A
  • exogenous - irritants (e.g. nappy rash), contact (delayed type IV hypersensitivity reaction to allergen), atopic, skin infections (e.g. S. aureus), food allergens, inhalant allergens (dust mites)
  • endogenous - atopic, seborrheic, pompholyx (affects hands and feet), varicose, lichen simplex
  • varicose - due to increased venous pressure in lower limbs
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7
Q

What is the genetic basis of eczema?

A
  • genetics –> polygenetic inheritance –> predisposition for increased IgE formation and sensitisation AKA type I hypersensitivity
  • filaggrin gene mutations increase risk
  • links identified between eczema and areas of genome that encode cytokines and receptors involved in the Th2 mediated immune response
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8
Q

What are some triggers for eczema? (5)

A
  • dust mites
  • heat
  • humid climate
  • stress
  • skin irritation
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9
Q

What are some risk factors for eczema? (5)

A
  • filaggrin gene mutation
  • age <5 years
  • family history of eczema
  • allergic rhinitis (hayfever)
  • asthma
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10
Q

What is contact dermatitis?

A

Type of eczema following exposure to a causative agent (Hx may say patient has a new occupation)

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11
Q

What is eczema herpeticum?

A
  • medical emergency where there is severe infection of skin by HSV 1 or 2
  • commonly seen in children with atopic eczema and presents as rapidly progressing painful rash with punched out erosions
  • potentially life threatening = children admitted for IV acyclovir
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12
Q

What are the signs and symptoms of eczema?

A
  • pruritus (may have excoriations/scratch marks)
  • xerosis (dry skin)
  • infants - cheeks, forehead, scalp, extensor surfaces (oedematous, prominent weeping and crusting)
  • children - flexures especially wrists, ankles and antecubital and popliteal fossae
  • chronic eczema often affects the neck, upper back, arms, hands, feet
  • acute flares (erythema, scaling, vesicles, papules)
  • lichenification (thick leathery skin due to scratching)
  • hyperpigmentation if chronic
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13
Q

What are the symptoms of an acute flare of eczema? (4)

A
  • erythema
  • scaling
  • papules
  • vesicles
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14
Q

What are the examination findings for acute eczema?

A
  • poorly demarcated erythematous oedematous dry scaling patches
  • papules
  • vesicles with exudation and crusting
  • excoriation marks
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15
Q

What are the examination findings for chronic eczema?

A
  • thickened epidermis
  • skin lichenification
  • fissures
  • change in pigmentation
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16
Q

What are the examination findings for atopic eczema?

A

Face and flexures affected

17
Q

What are the examination findings for seborrheic eczema?

A
  • yellow greasy scales on erythematous plaques
  • commonly found on eyebrows, scalp, presternal area
18
Q

What are the examination findings for pompholyx eczema?

A

Vesiculobullous eruption on palms and soles

19
Q

What are the examination findings for varicose eczema?

A

Associated with marked varicose veins

20
Q

What are the examination findings for nummular eczema?

A

Coin shaped on legs and trunk

21
Q

What are the examination findings for asteatoic eczema?

A

Dry crazy pairing pattern

22
Q

What is the 1st line investigation + investigations to consider for eczema diagnosis?

A
  • 1st line: clinical diagnosis
  • IgE levels (elevated)
  • skin-prick testing
  • oral food challenge
  • trial elimination diet
  • patch testing
  • skin biopsy (differentiate eczema from allergic contact dermatitis / mycosis fungoides / psoriasis)
23
Q

What diagnostic criteria is used for eczema?

A

Hanifin and Rajka Criteria
At least 3/4 major criteria + 3/23 minor criteria
Major: risk factors, pruritus, xerosis, sites of involvement = flexors in adults + extensors in infants
Minor: facial features, triggers, complications, others

24
Q

How do we test for contact dermatitis?

A
  • skin patching for type IV hypersensitivity
  • skin prick testing for type I hypersensitivity e.g. food allergies or urticaria
  • +ve = red raised lesion
25
Q

What are some differential diagnoses for eczema?

A
  • seborrheic dermatitis - greasy scale, not pruritic
  • irritant contact dermatitis - due to exposure to irritants, less pruritic than eczema, do patch test
  • allergic contact dermatitis - well-circumcised erythematous lesions often with spongiotic papules, vesicles, crusting, pruritic, asymmetric
  • scabies - severe pruritus, evident burrows, Fx, use microscopy
  • psoriasis - well-circumcised, erythematous lesions with silver scale, extensor surfaces, nail pitting
  • mycosis fungoides - erythematous plaques in random distribution, scale, older, do skin biopsy and cell flow cytometry
26
Q

In eczema, how do we rehydrate and improve the skin barrier?

A

Emollients - may contain a humectant (e.g. glycol/urea) that promotes hydration of the stratum corneum + occlusive agent (e.g. petrolatum) that reduces evaporation

27
Q

What is the 1st line treatment algorithm for acute flares of eczema?

A
  • emollient
  • consider topical corticosteroids (e.g. hydrocortisone)
  • consider topical calcineurin inhibitor (e.g. pimecrolimus/tacrolimus)
  • consider topical crisaborole
  • consider topical ruxolitinib
  • consider topical or oral antibiotic therapy (if infection suspected)
28
Q

What is the 2nd line treatment algorithm for acute flares of eczema?

A
  • systemic immunosuppressive agent (prednisolone / ciclosporin)
  • PLUS emollient
  • consider topical corticosteroid (e.g. hydrocortisone)
  • consider topical calcineurin inhibitor
  • consider topical crisaborole
  • consider topical or oral Abx therapy
29
Q

What is the 1st line treatment algorithm for chronic/relapsing eczema?

A
  • emollient
  • consider topical corticosteroids (e.g. hydrocortisone)
  • consider topical calcineurin inhibitor (e.g. pimecrolimus/tacrolimus)
  • consider topical crisaborole
  • consider topical ruxolitinib
30
Q

What is the 2nd line treatment algorithm for chronic/relapsing eczema?

A
  • systemic immunosuppressive agent (prednisolone / ciclosporin)
  • PLUS emollient
  • consider topical corticosteroid (e.g. hydrocortisone)
  • consider topical calcineurin inhibitor
  • consider topical crisaborole
31
Q

What is the 2nd line treatment algorithm for chronic/relapsing eczema, if moderate to severe?

A
  • phototherapy
  • PLUS emollient
  • consider topical corticosteroid (e.g. hydrocortisone)
  • consider topical crisaborole
  • consider topical ruxolitinib
32
Q

What do topical corticosteroids do to help eczema?

A
  • used when skin does not respond to regular moisturiser use
  • reduce inflammation and pruritus
  • used in acute flare-ups
  • higher potency in flare-ups and milder ones for maintenance
    • low-potency: hydrocortisone
    • mid-potency: fluticasone
    • high-potency: mometasone
    • very high-potency: clobetasol
33
Q

What do topical calcineurin inhibitors do to help eczema?

A

Lessens pruritus; consider in addition to topical corticosteroids or as monotherapy

34
Q

What does topical crisaborole do to help eczema?

A
  • topical non-steroidal anti-inflammatory phosphodiesterase-4 inhibitor
  • improves disease severity + pruritus in patients with mild-moderate eczema
35
Q

What does UV light therapy do to help eczema?

A
  • used in management of moderate-severe generalised eczema
  • immunosuppressive
  • immunomodulating
  • anti-inflammatory
36
Q

What are some complications of eczema?

A
  • psychological stress
  • adverse effects of drugs:
    • systemic adverse effects of corticosteroids e.g. Cushing’s, HPA suppression
    • malignancy related to topical calcineurin inhibitors
    • systemic adverse effects of cyclosporin
  • bacterial cutaneous infection
37
Q

What is the prognosis of eczema like?

A
  • chronic disease with a varying course
  • approximately 60% of children will have symptom resolution as they enter puberty but relapse may occur in 50%