eczema, dermatitis and psoriasis Flashcards
define eczema/dermatitis
used interchangeably, group of skin conditions characterised by dry, itchy, irritated skin
what is atopic eczema
adaptive immune response, causing a type IV hypersensitivity reaction
atopic eczema epidemiology
most common 30% of skin issues seen by GPs 1-2% adults 15% children
atopic eczema aetiology
genetics - filaggrin gene normally maintains skin barrier
atopic eczema pathophysiology
- Allergen presented to T cell by dendritic - TH2 –> IL4- B cell activation - IgE release –> mast cell activation Pro-inflammatory mediator release
clinical features of atopic eczema
- Age specific * Flexural in children * Hands in adults- Dry, itchy skin - Red/grey patches - Skin infections may occur
what are the options for treating atopic eczema
prevention - moisturising, avoiding triggers treatment - 1st emollients, steroids, abx, phototherapy2nd - oral steroids, top calcineurin inhib, immunosuppressants, dupilimumab, alitretinoin
what is dupilimumab and what is it used for
IL4 inhibitor, used for severe atopic eczema
what is alitretinoin and what is it used for
oral retinoid for hand eczema refractory to steroids
what is contact dermatitis
irritant or allergic type IV hypersensitivity reaction
what is the epidemiology of contact dermatitis
adults > children 75% of cases
aetiology of contact dermatitis
wet workatopic eczema increased risk of contact
aetiology of irritant contact dermatitis
irritant exposure detergents strip skin amount of exposure is important
aetiology of allergic contact dermatitis
over time of exposure immune response build up
pathophysiology of irritant contact dermatitis
innate response keratinocytes release TNF IL1/8endothelial upregulation and cellular recruitment
pathophysiology of allergic contact dermatitis
adaptive immune response T cell activation T reg and mast cell activation
treatment of contact dermatitis
avoiding irritants emollients topical or oral steroids alitretinoin
what is seborrheic dermatitis
skin flakes or cradle cap
epidemiology of seborrheic eczema
1-3% of the population more common in males over 20y/o
aetiology of seborrheic eczema
overgrowth of Malassezia yeast which usually exists on the skinin children its caused by immature sebaceous glands
pathophysiology of seborrheic eczema
sebum metabolised into proteins that penetrate and irritate the scalp
clinical features of seborrheic eczema in adults
flaky, itchy, inflamed skin with white/yellow scale
clinical features of seborrheic eczema in infants
yellow, waxy scales on the scalp pink, flaky patches on the forehead, eyebrows, behind ears and nappy area
treatment of seborrheic eczema in adults
shampoo - ketoconazolemild steroids - salicylic acid/anti-yeasts clotrimazole, miconazole, nystatin oral anti-fungal
treatment of seborrheic eczema in infants
emollients/mineral oilstopical steroids with an antifungal for the body
what are the different types of psoriasis
plaque scalp guttate pustular nail
what is plaque psoriasis
most common type red, sore, itchy skin with silver scales
what is scalp psoriasis
thick build up of skin on the scalp
what is guttate psoriasis
normally triggered by strep, pink/red (dark) rash on torso, back and limbs
what is pustular psoriasis
small, yellow filled pustules on red skin that crust once burst palms of hands/soles of feet but can spread derm treatment
what is nail psoriasis
50% of pts get it often mistaken for fungal nail discolouration, pitting, crumbling, cracking
epidemiology of psoriasis
2-3% of population peaks in late teens, 30s and 50-60
aetiology of psoriasis
genetic - 1/4 children with infected parentstrigger event - stress/injury/infectionPSOR1 gene or IL23/12 mutation
pharmacology of psoriasis
- keratinocytes stressed - release DNA and LL37 2. DNA/LL37 bind and are presented to T cells 3. dendritic cells release IL23 - T cell activation 4. TH and macrophage infiltrate keratinocyte layer 5. keratinocyte hyperproliferation
topical treatment for psoriasis
topical moisturisers, emollients, vit d derivatives, steroids, coal tar, calcineurin inhibphototherapy systemic immunosuppressants, acitretin, biologics
which biologics are used for psoriasis
anti-TNF - infliximab anti-IL23 - ustekinumab anti-IL12
how do vitamin D derivatives work in psoriasis
inhibits proliferation and induces keratinocyte differentiation
what is psoriatic arthritis
inflammatory joint/tendon disease - tender, swollen and stiff
what is the treatment for psoriatic arthritis
painkillers corticosteroids DMARDs - leflunomide biologics - anti-tnf, jak inhibitors
what are the other forms of eczema
nummular neurodermatitis stasis dishidrotic
what is nummular eczema
oval, blistered lesions on lower legs, trunk and arms - emollients, steroids, abx and phototherapy
what is neurodermatitis eczema
persistent and recurring, treated with emollients and topical steroids
what is stasis eczema
fragile, thin, shiny, itchy skin in adults in varicose veins - emollients, steroids, compression stockings
what is dyshidrotic eczema
itchy blisters on hands and feet, aggravated by heat and stress - emollients, steroids, abx, immunosuppressants
NICE guidelines for the treatment of mild atopic eczema
managing triggers emollients mild top. steroid
NICE guidelines for the treatment of moderate atopic eczema
managing triggers emollients moderate top. steroid top. calcineurin inhibocclusion
NICE guidelines for the treatment of severe atopic eczema
managing triggers emollients moderate top. steroid top. calcineurin inhibocclusionphototherapy systemic steroids/immune suppress plus abx if inf - fluc, eryth, clarith
NICE guidelines for the treatment of psoriasis
- emollient, vit d analogue, top. steroid, dithranol, coal tar 2. UVB/PUVA, methotrexate/ciclosporin, acitretin 3. biologics
how does dithranol work
- Anti-proliferative effect on epidermal keratinocytes
how does UVB/PUVA work
- UVB slows cell proliferation - Psoralen is light activated to interfere with DNA
how does acitretin work
- Oral vit d analogue - Induces keratinocyte differentiation and reduces epidermal hyperplasia
