Psoriasis Flashcards

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1
Q

Psoriasis - intro

A
  • Bimodal onset - peaks 3rd and 6th decades
  • abnormal T cell activation causes keratinocyte proliferation and early migration
  • genetic links: HLA CW6, HLA B27 (linked with psoriatic arthritis)
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2
Q

Psoriasis - triggers

A
  • infection: e.g. Strep throat (beta haem strep), HIV
  • durgs: e.g. beta blockers, lithium, anti-malarials
  • alcohol*
  • pregnancy
  • stress
  • light treatment (used for psoriasis, but in some cases can make it worse)
  • trauma to skin (Koebner phenomenon)

*alcohol makes psoriasis worse and contributes to liver abnormalities in pts at risk of NAFLD

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3
Q

Patterns of Psoriasis - Chronic Large Plaque

A
  • erythematous injurated (thick and stiff on palpation) plaques
  • thick silvery scales
  • very well demarcated (as opposed to eczema)
  • locations: extensors, scalp, gluteal cleft, genitalia
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4
Q

Guttate Psoriasis

A
  • raindrop lesion = scaly papules, generally on trunk
  • usually younger patients
  • commonly preceded by strep throat
  • predisposes to plaque psoriasis later in life
  • treated with phototherapy
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5
Q

Palmar Plantar Pustulosis

A
  • pustules on sheaths of tense sterile blisters on hands and feet
  • resolve and leave brown macules
  • almost always a smoking history
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6
Q

Nail Psoriasis

A
  • nail pitting, onycholysis (nail lifts off nailbed), subungual keratosis (thickened keratin underneath nail)
  • can also get leukonychia
  • predisposes to psoriatic arthritis
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7
Q

Pustular Psoriasis

A
  • patient quite unwell - malaise, fever
  • widespread erythema with pustules
  • common in hands but can involve whole body
  • common trigger is withdrawal of oral steroids* (also infections, hypercalcemia and pregnancy)

*you should not give oral steroids to psoriasis patients (due to risk of it becoming pustular when you withdraw them)

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8
Q

Flexural Psoriasis

A
  • difficult to spot as not typically scaly, but shiny and only slightly raised
  • can have fissure in the crease
  • can be misdiagnosed as a fungal infection (e.g. tinia), but those are usually unilateral while psoriasis bilateral
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9
Q

Extra-systemic presentations

A
  • IBD
  • Psoriatic Arthritis
  • Metabolic Syndrome
  • Mental Health
  • increased CV risk

hence ask about other systems in psoriasis history - esp. MSK and CVS

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10
Q

(Exam question)

Rash following sore throat? - DDx

A
  • Guttate Psoriasis
  • Small vessel vasculitis
  • Glandular Fever (treated with penicillin)
  • Drug Rash
  • Pityriasis rosea
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11
Q

Is psoriasis itchy?

A

It can be itchy, but not a hallmark

  • if patient presents with a lot of itching, rule out:
    1. scabies
    2. dermatitis herpetiformis (coeliac’s)
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12
Q

Psoriatic Arthritis - main features

A

Psoriatic Arthritis: asymmetrical oligoarthritis - nail changes, fingers/toes (dactylytis), DIP/RA like, Spondylitis/Sacroilitis,

  • usually seronegative (-ve RF)
  • HLA B27
  • PEST score: screening tool for psoriatic arthritis (used to refer patients to rheumatology)
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13
Q

Treatment - overview

A
  • emollients (ointments better than creams)
  • topical steroids
  • vitamin D3 analogues
  • coal tar
  • dirthranol
  • light treatment
  • Immunosuppressants
  • Biologics
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14
Q

Vitamin D3 Analogues

A
  • e.g. calcipotriol, calcitriol
  • limit use - as they can cause hypercalcaemia
  • preparations include vit D3 analogues alone (e.g. dovonex) or combined with topical steroid, e.g. dovabet (contains betnovate - potent steroid)
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15
Q

Other Topical Treatments

A
Coal Tars (cream, ointment)
- smelly and stain skin, can cause skin irritation so use cautiosly on flexures

Dithranol (paste or cream)

  • usually as inpatient or day care, as it stains a lot and can also burn skin, so only used on thick plaques (only suitable for large plaque psoriasis)
  • can be used with phototherapy
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16
Q

Light Treatment

A
  • good for guttate psoriasis

2 types

  • UVB light: TL01
  • UVA light: PUVA - uses psolaren (either with bath or tablet) that photosensitises skin
  • 2-3 times a week for 6-8 weeks, so patient must be able to commit
  • need to think about risk of skin cancer (UVB is safer)
  • pt needs to be stable and stand for a few minutes so if very old or frail might not be appropriate
17
Q

Immunosuppression

A
  • ciclosporin*
  • methotrexate**
  • hydroxycarbamide
  • fumaric acid
  • acitretin

(warn patients of increased risk of infection and cancers with immunosuppression)

  • check renal function and BP
    ** check liver function, alcohol intake and nausea
    (also FBC)
18
Q

Biologics

A
  • e.g. anti TNF* (adalimumab, etanercept, infliximab)
  • generally injection or IV infusion for infliximab (need to come for a day)
  • criteria for use of biologics: PASI > 10 and DLQI (self questionnare) > 10 + must have failed on 2 systemic treatments (usually mtx and cyclosporin)

*must screen for TB prior as they can reactivate TB