Psoriasis

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Psoriasis
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Definition

• Chronic plaque psoriasis (psoriasis vulgaris) is
  a chronic inflammatory skin disease characterised
  by well demarcated erythematous scaly patches on
  the extensor surfaces of the body and scalp
• Lesions may itch, sting and occasionally bleed
• Dystrophic nail changes are found in gt 1/3
• Psoriatic arthropathy occurs in 1-gt10
• Condition waxes and wanes with wide variations
  between individuals
• Other types guttate, inverse, pustular,
  erythrodermic

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Epidemiology of psoriasis

• Affects 1.5 in UK
• Ethnic variation
• Rare in Japan and China
• M F
• Bimodal age distribution
• Commonest between 10 and 20 years and around 50
  years
• Many cases mild
• Can be very stigmatising
• 5 get episodes of severe disease
• Precipitants / aggravants
• Alcohol, NSAIDs, B blockers, Lithium,
  antimalarials

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Pathology

• Rapid proliferation of keratinocytes (x7 normal
  rate) causes acanthosis thickening of epidermis
  due to increased numbers of acanthocytes (prickle
  cells)
• Incomplete differentiation and maturation causes
  cells to be shed in abnormally large clumps
• Dilatation and elongation of capillaries
  apparent at surface
• Infiltration of dermis and epidermis by
  inflammatory cells causes microabscesses and
  micropustules pustular psoriasis
• Cause unknown. Though to be autoimmune genetic
  influence 30 have a relative with the condition

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Chronic plaque psoriasis

• Commonest type
• Scaly erythematous plaques red, white-silver
  scale, well demarcated
• Itch common, pain unusual
• Symmetrical distribution
• Common sites
• Scalp, elbows, knees, shins and sacrum
• Nail involvement common
• Koebners phenomenon useful pointer
• Activity varies over months to years, remission
  common, sometimes induced by treatment

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Guttate psoriasis

• Acute eruption of small plaques (typically 1cm)
  over trunk and limbs
• Triggered by URTI particularly streptococcal
  sore throat

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Palmopustular psoriasis

• More often affects women
• Strong correlation with smoking
• Chronic relapsing course, difficult to treat
  (often needs systemic treatment)
• Can be painful
• When occurs on its own, difficult to distinguish
  from eczema

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Nail psoriasis

• Pitting and onycholysis, subungal hyperkeratosis
• Can occur in isolation

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Flexural and genital psoriasis

• Looks different, not always scaly
• Exudation prominent

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Scalp psoriasis
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Severe types / manifestations of psoriasis

• Generalised pustular psoriasis
• Often erupts suddenly. Life-threatening
• Some cases associated with withdrawal of topical
  or systemic steroids
• Sheets of small pustules merge
• Associated pyrexia and systemic illness
• Sepicaemia, shock, dehydration can occur
• Erythrodermic psoriasis
• Usually seen in neglected or poorly controlled
  severe psoriasis
• Severe erythema and scaling over entire body
  surface
• Psoriatic arthritis

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General assessment disease severity

• Patient satisfaction
• Disease related quality of life
• Surface area covered
• lt5 is mild one palm area 1 body area
• 5-20 is moderate often requires hospital
  intervention, usually topical / oral regimen with
  UV light therapy
• gt20 is severe requires systemic therapy

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Many therapies

• Community based

• Hospital led

• Emollients
• Topical coal tar
• Topical dithranol
• Topical vitamin D and analogues
• Topical corticosteroids
• Topical retinoids
• Plus combinations

• Phototherapy
• Methotrexate
• Oral retinoids
• Cyclosporin
• Hydroxyurea
• Azathioprine
• Systemic steroids
• TNF-alpha drugs
• T-cell drugs efalizumab, alefacept

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British association of Dermatologists
recommendations

• Emollients soften scaling and reduce irritation
• For localised plaque psoriasis one or more of the
  following can be used
• Tar based cream or tar/corticosteroid mixture
• Moderate potency topical corticosteroid eg
  eumovate
• Stronger agents can be used on the palms and
  soles or on the scalp
• Vitamin D analogue
• Calcipotriol with betamethasone dipropionate
  combination product
• Vitamin A analogue (tazarotene)
• Dithranol preparation
• Use a keratolytic agent (eg 5 salicylic acid in
  emulsifying ointment) first when there is
  significant scaling or other treatments fail

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Topical tar

• Newer cleaner creams more acceptable up to
  10 coal tar
• Stronger crude preparations are usually part of
  hospital based treatment
• Shampoo particularly useful
• Traditionally been used combined with UVB therapy
  (Goeckermann treatment)
• Trend towards alternating applications with
  topical steroids

• Expensive now!
• Tried and tested (100 years plus)
• Smelly
• Can stain clothing and skin
• Safety concerns (no long term evidence of
  increased cancer risk)

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Dithranol

• Best suited to largeish, well-defined plaques
• Not for flexures
• Start with low strength and build up, from 0.1 up
  to 3
• Miconal is a newer product claiming to release
  dithranol at body temp (and causes less staining)
• Apply for 30 mins and wash off )vary between 5
  and 60 mins

• Tried and tested (50y)
• Cheap
• Not easy to use
• Wear gloves or wash off hands carefully
• Irritating and can burn healthy skin
• Stains (brown/purple) skin, clothes, bath etc

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Vitamin D and analogues

• Calcipotriol
• OD or BD
• Irritation redness, soreness and pruritis
  common (20)
• Not to be used on face or flexures
• No more than 100g per week (risk of
  hypercalcaemia)
• Calcitriol
• BD
• Max 30g daily
• Not children
• Can be used on creases and face
• Tacalcitol
• Once daily
• Not children
• Max 10g per day
• Can be used on creases and face

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Topical steroids

• Effective in short term, relatively cheap
• Generally liked by patients not smelly / messy
• Early improvement not sustained
• Do not use more than 4 weeks
• Problem is rebound effects or aggrevation
  /instability
• Mild steroid useful for creases and face
• Potent steroid often useful as initial treatment
  for scalp, hands and feet
• Can be used with dithranol, coal tar, vitamin D
  and analogues
• Dovobet allows steroid and calcipotriol
  application at the same time

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Dovobet betamethasone 0.05 with calcipotriol

• OD or BD
• Indicated for stable plaque psoriasis (age
  greater than 18)
• Not to be applied to scalp, face, mouth (or eyes)
  also avoid creases
• Max 4 weeks, max 15g/day, 100g/week
• No more than 30 of total body surface

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Tazarotene (Zorac)

• Indicated for mild to moderate plaque psoriasis
  affecting up to 10 of skin area
• OD up to 12 weeks not on face
• Not recommended under 18
• Teratogenic must not be used in pregnancy
• Helps regulate abnormal proliferation of
  keratocytes
• Can be quite irritant but is clean and convenient
• DTB advise not using first line
• Potential for use in combination therapy

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Trend is towards combination therapy

• All topical therapies have limitations
• Irritation, staining, smell, inconvenience etc
• Most work through different mechanisms so effects
  might be additive or synergistic
• Potential for combining approaches
• Improving therapeutic effects
• Minimizing adverse effects

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Special sites skin creases, genitals

• Tricky to diagnose and treat
• Appearance may not be typical erythema
  prominent, scale not evident, may exude
• Topical corticosteroids often used but avoid high
  potency these areas prone to skin atrophy
• Use creams rather than ointments
• Tacalcitol may be used
• Calcipotriol may be too irritant

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Scalp

• Tends to be visible and stigmatising
• Is difficult to manage
• Soften thick scale with coconut or arachis oil,
  can be left on overnight, under shower cap (with
  salicylic acid, if required)
• Remove using combing and shampoo tar based
• Apply coal tar, dithranol, or topical steroid
  preparation
• Newer calcipotriol scalp application is an
  alternative

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Psoriatic arthropathy

• 15-20 attending hospital develop inflammatory
  arthritis
• May be lt10 in the community
• Slight female predominance
• Most have pre-existing skin or nail psoriasis
  (joint inflammation precedes psoriasis in 15 of
  cases)

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