Psoriasis Flashcards by Nader Raafat

Epidemiology of psoriasis

2% of population

Equal sex incidence

2nd-3rd and 6th decade (bimodal peak incidence)

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Aetiology of psoriasis

Hyperproliferation of keratinocytes and inflammatory cell infiltration

Ppt by trauma (Kobner), infection (esp strep throat), drugs, stress, alcohol

UV light helps but not always (lowest incidence equator)

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Types of psoriasis

Chronic plaque

Guttate - post-streptococcal

Seborrheic

Flexural

Pustular

Erythrodermic

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Features of psoriasis plaques

Silvery, rough scale

Clearly demarcated

Erythematous background

Can be itchy, burning, painful

Auspitz sign - pinpoint bleeding when they’re touched

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Nail changes in psoriasis

Affects 50%

Onycholysis

Pitting

Subungual hyperkeratosis

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Koebner phenomenon

Rash ‘colonises’ site of recent trauma (e.g. excoriation) - line marking

Esp tattoos

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Distribution of psoriasis

Extensor surfaces

Scalp

Palmo-plantar

Retro-auricular

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Auspitz sign

Removal of psoriasis scale results in pinpoint capillary bleeding

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Drugs exacerbating psoriasis

Antimalarials

Beta blockers

Lithium

Acute steroid withdrawal

Rampant psoriasis

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Complications of psoriasis

Erythroderma

Social phobia, depression

Vit D deficiency, deconditioning

Skin atrophy from prolonged potent topical steroids

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Differential between seb derm and seb psoriasis

Psoriasis more sharply demarcated

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Differential between psoriasis and eczema

Eczema more itchy

Less well demarcated

Flexor > extensor

Less erythematous

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Clinical course based on early vs late onset

Early onset - 16-22

Irregular course, more severe, increased psych comorbidity, tendency to become generalised

Late onset - 57-62

Milder, more localised

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Pathogenesis of psoriasis

T-cell driven

Th1: TNF-a, IL-2, IFN-g

Th17: IL-17 for neutrophils, IL-23 for keratinocyte proliferation and keratosis

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Chronic plaque psoriasis

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Management of psoriasis - patient education

Control not cure

Avoid known triggers

Emollients to reduce scale (esp for scalp)

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Topical treatments for psoriasis

Localised, mild disease

Vit D analogues

Coal tar preparations

Topical retinoids/VitA analogues

Topical steroid

Anti-yeast (seborrheic)

alongside emollient

Most topicals may cause irritation

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Inverse psoriasis

Friction > loss of scale > shiny plaque or fissure

Guttate psoriasis

Associated with infection (Esp strep throat) in adolescence

Raindrop, ‘spotty’ lesions

Palmo-plantar pustular psoriasis

Collection of neutrophils

Can result from inappropriate sue of oral steroids

If generalised > skin failure

Assessment of psoriasis severity

PASI

Looking at thickness, erythema, coverage, scale

In: head + neck, trunk, upper limb, lower limb

Patterns of psoriatic arthritis

Distal interphalangeal joint

Dactylitis

Arthritis mutilans (DIP flexion deformities, digit shortening)

Symmetrical polyarthritis (RA-like)

Spondyloarthritis

Asymmetrical oligoarthritis

Comorbidities with psoriasis

Psychiatric - depression/anxiety

Metabolic syndrome and CVD - from inflammation

Smoking/alcohol - cause and effect? worsen illness

Name of vitamin d analogue

Calcipotriol

May cause hypercalcaemia with prolonged use

Name of coal tar analogue

exorex will stain bedsheets! Advise patient

Management of scalp psoriasis

Coal tar based treatment/emollient overnight to descale Steroid for inflammation Anti-yeast

Forms of psoriasis phototherapy

Narrow band UVB Psoralen-PUVA (can be hand/feet only)

Narrow band UVB therapy

311-312nm - most effective w/ least cancer risk 3x per week for 8 weeks

UVA therapy

Psoralen taken prior to therapy (topical if hands/feet) Psoralen absorbs UVA light - sensitises skin Then twice weekly Caution if prev immunosuppression

Systemic management of psoriasis

Methotrexate Acitretin Ciclosporin Fumaric acid esterase, mycophenolate mofetil less common

Methotrexate monitoring

Teratogenic - not pregnancy (but can be given to females) Limit EtOH Hepatitis, myelosuppression risk - FBC, LFTs, U&Es Folate supplementation

Methotrexate side effects

Nausea + vomiting Oral ulcers Myelosuppression, hepatitis Teratogenic - encourage contraception until 6mo after stopping Caution if suspecting infection to acute myelosuppression

Methotrexate dosing

10-25mg Once-weekly

Acitretin side effects

Vit A derivative (retinoid) Mucocutaeneous dryness Mood disturbance LFT and lipid profile monitoring Teratogenic - **contraception 1mo before and 3 years after stopping**

Ciclosporin side effects

Renal impairment Increased blood pressure Short-term treatment only

Acitretin dose

25mg daily

Ciclosporin ose

2.5-5mg/kg daily in two divided doses

NICE eligibility criteria for biologics

DLQI \>10 PASI \>10 Failed systemic treatment + phototherapy

Biologic targets

TNF-a IL-17 IL-12/23

TNF-a biologics

Adalimumab Etanercept Infliximab

IL-17 biologics

Secukinumab Brodalumab (receptor antagonist)

IL-12/23 biologics

Ustekinumab Inhibits p40 subunit

Differential for nail pitting

Eczema Lichen planus Psoriasis