Atopic dermatitis & eczema (DERM) Flashcards
Define eczema.
Inflammatory skin condition characterised by dry, pruritic skin with a chronic relapsing course
What demographic does eczema typically affect?
M=F, usually presents in childhood (most commonly diagnosed before 5 years, affects 10-20% of children)
What do patients with eczema usually have a history of?
Personal or family history of atopic diseases e.g. asthma or allergic rhinitis
How can eczema be described? (2 types)
- acute (flare-up of symptoms)
- chronic (when the patient develops signs of chronic inflammation e.g. lichenification)
What are the typical features of eczema? (4)
- erythema
- scaling
- vesicles
- lichenification in skin flexures
What are the three types of eczema?
- 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
What is the genetic basis of eczema?
- 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
What are some triggers for eczema? (5)
- dust mites
- heat
- humid climate
- stress
- skin irritation
What are some risk factors for eczema? (5)
- filaggrin gene mutation
- age <5 years
- family history of eczema
- allergic rhinitis (hayfever)
- asthma
What is contact dermatitis?
Type of eczema following exposure to a causative agent (Hx may say patient has a new occupation)
What is eczema herpeticum?
- 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
What are the signs and symptoms of eczema?
- 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
What are the symptoms of an acute flare of eczema? (4)
- erythema
- scaling
- papules
- vesicles
What are the examination findings for acute eczema?
- poorly demarcated erythematous oedematous dry scaling patches
- papules
- vesicles with exudation and crusting
- excoriation marks
What are the examination findings for chronic eczema?
- thickened epidermis
- skin lichenification
- fissures
- change in pigmentation
What are the examination findings for atopic eczema?
Face and flexures affected
What are the examination findings for seborrheic eczema?
- yellow greasy scales on erythematous plaques
- commonly found on eyebrows, scalp, presternal area
What are the examination findings for pompholyx eczema?
Vesiculobullous eruption on palms and soles
What are the examination findings for varicose eczema?
Associated with marked varicose veins
What are the examination findings for nummular eczema?
Coin shaped on legs and trunk
What are the examination findings for asteatoic eczema?
Dry crazy pairing pattern
What is the 1st line investigation + investigations to consider for eczema diagnosis?
- 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)
What diagnostic criteria is used for eczema?
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
How do we test for contact dermatitis?
- skin patching for type IV hypersensitivity
- skin prick testing for type I hypersensitivity e.g. food allergies or urticaria
- +ve = red raised lesion
What are some differential diagnoses for eczema?
- 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
In eczema, how do we rehydrate and improve the skin barrier?
Emollients - may contain a humectant (e.g. glycol/urea) that promotes hydration of the stratum corneum + occlusive agent (e.g. petrolatum) that reduces evaporation
What is the 1st line treatment algorithm for acute flares of eczema?
- 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)
What is the 2nd line treatment algorithm for acute flares of eczema?
- 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
What is the 1st line treatment algorithm for chronic/relapsing eczema?
- emollient
- consider topical corticosteroids (e.g. hydrocortisone)
- consider topical calcineurin inhibitor (e.g. pimecrolimus/tacrolimus)
- consider topical crisaborole
- consider topical ruxolitinib
What is the 2nd line treatment algorithm for chronic/relapsing eczema?
- systemic immunosuppressive agent (prednisolone / ciclosporin)
- PLUS emollient
- consider topical corticosteroid (e.g. hydrocortisone)
- consider topical calcineurin inhibitor
- consider topical crisaborole
What is the 2nd line treatment algorithm for chronic/relapsing eczema, if moderate to severe?
- phototherapy
- PLUS emollient
- consider topical corticosteroid (e.g. hydrocortisone)
- consider topical crisaborole
- consider topical ruxolitinib
What do topical corticosteroids do to help eczema?
- 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
What do topical calcineurin inhibitors do to help eczema?
Lessens pruritus; consider in addition to topical corticosteroids or as monotherapy
What does topical crisaborole do to help eczema?
- topical non-steroidal anti-inflammatory phosphodiesterase-4 inhibitor
- improves disease severity + pruritus in patients with mild-moderate eczema
What does UV light therapy do to help eczema?
- used in management of moderate-severe generalised eczema
- immunosuppressive
- immunomodulating
- anti-inflammatory
What are some complications of eczema?
- 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
What is the prognosis of eczema like?
- chronic disease with a varying course
- approximately 60% of children will have symptom resolution as they enter puberty but relapse may occur in 50%
