Psoriasis Flashcards

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1
Q

What is psoriasis?

A
  • common, chronic inflammatory skin condition
  • raised, red, (itchy), scaly plaques on extensor surfaces
  • T-cell mediated abnormal immune response causing keratinocyte hyperproliferation
  • strong genetic component
  • link to arthritis
  • subtypes eg guttate or palmar-pustular
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2
Q

Epidemiology of psoriasis?

Risk factors?

A
  • affect 2-4% of the population
  • any age but bimodal peak at 15-25 and 50-60 years
  • 3rd of patients have a relative with it
  • more common in caucasians

Risk factors:

  • genetic susceptibility
  • smoking
  • obesity
  • psychological stressors
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3
Q

Pathology of psoriasis?

A

keratinocyte hyperproliferation

Biopsy:

  • parakeratosis (retained nuclei)
  • acanthuses (thick epidermis)
  • absent granular layer
  • thin dermal papillae
  • dilated, tortuous capillaries
  • munro’s micro-abscesses
  • T-cell in upper dermis
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4
Q

Clinical features of psoriasis?

Types?

A
  • symmetrical
  • red scaly plaque (plaque is white or silvery)
  • often on extensors
  • scalp (behind ears), elbows, knees, anywhere

TYPES

Classical:

  • 90% of cases
  • well circumscribed, erythematous with silver scale >3cm
  • esp extensor surface
  • pain and itch (less than eczema)
  • auspitz sign (bleeding on removal of scale)

Guttate:

  • young onset
  • often following streptococcal tonsillitis
  • discoid erythematous scaly macules and plaques on TRUNK
  • usually <3cm
  • good prognosis, will usually resolve in several months

Palmoplanar-pustular:
- yellow brown pustules on palms and soles

Flexoral:

  • plaques are erythematous but not scaly
  • submammary, axillary, anogenital, umbilical
  • esp women, elderly, and HIV
  • hard to tell from eczema

Nail features:

  • pitting
  • onycholysis (lifting off bed)
  • subungal hyperkeratosis
  • beaus lines (horizontal across nail)

Psoriatic arthritis

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5
Q

Differential diagnoses when considering psoriasis?

A
  • dermatitis / eczema (discoid or seborrheic )
  • lichen planus
  • Pityriasis rosea (esp guttate psoriasis)
  • 2nd stage of syphilis
  • reiter’s syndrome (esp palmoplanar psoriasis)
  • discoid lupus
  • syphilis
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6
Q

Precipitating factors for psoriasis?

A
  • trauma (Koebner’s phenomena)
  • infection
  • drugs: beta-blockers, lithium, antimalarials, NSAIDs, ACEi
  • stress
  • sunlight
  • puberty
  • menopause
  • alcohol
  • obesity
  • smoking
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7
Q

Disorders associated with Psoriasis?

A
  • psoriatic arthritis (within 10 years of derm, also ank spond)
  • IBD
  • uveitis
  • coeliac disease
  • metabolic syndrome (T2DM, HTN, high lipids, gout, CVD)
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8
Q

Management of psoriasis?

A

LIFESTYLE
- minimise risk factors (smoking, alcohol, weight, avoid sun, stress)

TOPICAL:
- emollients

  • CORTICOSTEROIDS are mainstay
  • prescribe with VIT D analogue
  • potent eg betamethasone 0.1% (betnovate)
  • combined with Vit D eg daivobet or enstillar foam
  • hydrocortisone for face
  • Vit D analogues (Calcipotriol, tacalcitol, calcitriol)
  • decrease cell proliferation
  • can cause skin irritation and hypercalcaemia
  • coal TAR preparations
  • inhibit DNA synthesis
  • smelly, messy
  • good for scalp psoriasis
  • dithranol (anthralin, decrease cell proliferation, irritates neighbouring skin, stains clothes)
  • keratolytics (salicylic acid)
  • retinoids (tazarotene)

SYSTEMIC
only in secondary care

  • UVB (for classic and guttate, narrow band has low risk of burning)
  • PUVA (second line, gives more longterm damage and cancer risk, use with retinoids)
  • retinoids
  • acitretin
  • effect after 4-6 weeks, use for <6 months
  • teratogenic for up to 3 years
  • dry mucous membranes and hepatoxicity
  • immunosuppressants
  • methotrexate, also cyclosporin, azathioprine, hydroxurea
  • when above have failed
  • biologics
  • etanercept, adalimumab, infliximab
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9
Q

Prognosis of psoriasis?

A
  • variable course
  • often relapses
  • FHx and early onset is worse prognosis
  • over use of steroids can cause pustular flares
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