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what is the incidence of psoriasis worldwide?
2%
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where does psoriasis affect?
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what is sex preponderance of psoriasis?
f=m
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what is peak age onset of psoriasis?
2nd and 3rd decade
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what is the main pathogenesis of psoriasis?
- hyperproliferative disorder
- production of keratinocytes is increased 28 fold!
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which WBC type mediates psoriasis?
T cell - so its a Rx target
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what is parakeratosis?
when keratin layer have NOT lost their nuclei
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what is acanthosis?
thickening of epidermis
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what are the triggers of psoriasis? (8)
- infection - strep (guttate), HIV
- stress
- childbirth
- alcohol, smoking
- trauma - koebner
- drugs - steroids
- endocrine - pregnancy, hypocalcaemia
- sunburn
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what are the 5 types of psoriasis?
- plaque
- sebo-psoriasis (looks like seborrheic dermatitis)
- guttate
- erythrodermic
- pustular - generalised/localised
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which 2 types of psoriasis are emergencies?
- erythrodermic
- pustular - generalised/localised
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how would you describe plaque psoriasis?
- well defined plaque - FLAT, ELEVATED
- on extensor surface
- salmon pink
- thick silvery whicte scale
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where are common sites for chronic plaque psoriasis?
- symmetrical extensors
- umbilicus
- scalp
- genital
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what are the 4 nail signs of psoriasis?
- 1. onycholysis: lifting of nail plate off nailbed
- 2. pitting: small depressions in nail plate
- 3. longitudinal ridging
- 4. subungal hyperkeratosis
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what are the 5 types of psoriatic arthropathy?
- 1. asymmetric
- 2. symmetric polyarthritis
- 3. DIP
- 4. destructive (arthritis mutilans)
- 5. axial arthritis
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what causes guttate psoriasis?
post strep throat infection
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who gets guttate psoriasis?
young adults
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describe appearance of guttate psoriasis?
- shower of scattered discrete lesions
- up to 1cm
- round or slight oval
- small plaques on trunks/limbs
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what is Rx of guttate psoriasis?
light therapy
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what are the 2 types of pustular psoriasis?
- localised eg palmoplantar
- generalised - life threatening!
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what are features of palmoplantar pustular psoriasis?
palms and soles studded with sterile pustules on erythematous base
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what are features of generalised pustular psoriasis?
- life threatening
- abrupt onset
- fever
- very unwell
- indicates severe, unstable psoriasis
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what can precipitate pustular psoriasis?
use of steroids
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why is generalised pustular psoriasis an emergency?
- dehydration
- renal failure
- death
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what is Rx of Gen pustular psoriasis? 3 aspects
- 1. admit, ITU maybe needed
- 2. greasy emollients, iv support, avoid/treat infection
- 3. systemic therapy - acetretin or ciclosporin
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how would you describe erythrodermic psoriasis?
skin becomes universally red with scaling
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what are symptoms of erythrodermic psoriasis?
- malaise
- shivering
- skin hot and uncomfortable
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what are the complications of erythrodermic psoriasis?
- fluid loss
- heat loss - hypothermia
- infection as barrier loss
- hypercatablolic state
- shock
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what is Rx for erythrodermic psoriasis?
- admit ITU
- iv supportive
- greasy emollients
- treat/avoid infection
- systemic - acetretin/ciclosporin immunosupp
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what are the 5 step treatments for psoriasis?
- 1. emollients
- 2. topical agents
- 3. phototherapy
- 4. systemic agents
- 5. biological agents
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what are the 4 different topical treatments for psoriasis?
- vitamin D
- tar
- dithranol
- steroids
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what are the 2 types of phototherapy, difference?
- narrow band UVB
- pUVA=UVA plus psoralen
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what is puva?
- psoralen + UVA treatment
- psoralen is taken orally to photosensitise skin then expose to UVA
- P allows a lower dose of UVA to be used
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what are the systemic treatments for psoriasis based on?
t cell suppression
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give 5 eg of systemic Rx for psoriasis?
- retinoids: acetretin- reduce cell turnover
- immunosupp: methotrexate, ciclosporin, hydroxyurea
- fumaric acid
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what are the biological Rx for psoriasis?
anti TNF - monoclonal antibody
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what is lichen planus? what does it affect?
- inflammatory dermatosis
- affects skin, mucous membranes, nail, hair
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what are the 5 Ps to describe lichen planus?
- purple
- planar
- polished
- papular
- pruritic
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where does lichen planus tend to affect?
- skin: flexor surfaces - wrist, forearm
- genitals
- mouth: white striae
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what does LP in the mouth look like?
- reticulated lacy white patter
- wickham's striae
- leukoplakia
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what does LP in the mouth increase the risk of?
oral cancer
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what is the topical Rx for LP?
POTENT steroids
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what are the systemic Rx for LP? (4)
- steroids
- retinoids
- PUVA
- ciclosporin
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what is the natural history for LP?
most resolve in 1-2 years
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what is the diagnosis for an asymptomatic man with a large patch on his trunk followed by a rash 1 week later?
pityriasis rosea
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what is that patch called?
herald patch
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who does pityriasis rosea affect and what is cause?
- children/young adults
- viral cause? seasonal variation
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what does the actual rash of PR look like?
- oval erythematous papules
- some scale in middle
- t-shirt distribution
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what kind of pattern may PR form and why?
- lesions follow lines of dermatomes
- xmas tree pattern
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what is Rx of PR?
- no Rx usually
- if itchy then antihistamine (as the histamine is what makes itch)
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