Psoriasis Flashcards
pathogenesis of psoriasis
hyperproliferation of keratinocytes
- faster epidermal turnover time
what drives the inflammation in psoriasis
T cells (TH1 + TH17) IL-12, IL-17, IL-23
Histological features of psoriasis
parakeratotic stratum corneum (contains nuclei- usually none)
absence of granular layer
expanded prickle cell layer
trigger for flare ups of psoriasis
stress alcohol + smoking drugs: beta blockers, lithium, anti-malarial, steroid withdrawal Infection: strep throat Trauma - koebner phenomenon
what is the most common type of psoriasis?
how does it present?
chronic plaque psoriasis
- extensor aspects of knees, elbows, sacrum and scalp
- palpable, raised plaques with surface scale
- usually symmetrical
what is auspitz sign
removing scale reveals pin point bleeding
what is the koebner phenomenon
psoriasis may develop in sites of trauma 2-6 weeks after trauma sustained
- scratches
- burns
- surgical trauma
nail symptoms in psoriasis
pitting - small indentations
onycholysis- plate separation due to subungal hyperkeratosis
oil drop lesions - red/yellow discolouration
multiple small psoriatic lesions on trunk 7-10 days following streptococcal sore throat in young patient (15-25 years). Most likely diagnosis?
guttate psoriasis
- self limiting
- can use emollients
treatment of scalp psoriasis
Mild: tar based shampoo
Severe: potent steroid, then scale removal agent, then fit D analogue
appearance of flexural psoriasis
red, shiny smooth patches - less scaly- in groin/armpits
- can be confused with fungal infection
what is palmoplantar psoriasis
very thick hyperkeratosis on palms/soles
painful + disabling
treatment of palmoplantar psoriasis
topical tar preparations salicylic acid topical steroids phototherapy systemic immunosuppressants
features of pustular psoriasis
sterile pustules (neutrophils) on skin
painful skin, fever, malaise
hypoalbuminaemia, hypocalcaemia and leucocytosis frequent
causes of pustular psoriasis
withdrawal of steroids
pregnancy
lithium
hypocalcaemia
what is palmoplantar pustulosis
sterile yellow pustules fading to brown macules on hands/feet
strong association with smoking
treatment of pustular psoriasis
emollients
fluid balance
systemic therapy often needed - methotrexate / cyclosporin
features of erythrodermic psoriasis
> 90% of skin surface red
- usually in patient with known plaque psoriasis
complications of erythrodermic psoriasis
hypovolaemia
hypothermia
cardiogenic shock
treatment ladder for psoriasis
- topical therapy
- emollients
- tar preparations
- vit D analogues
- salicylic acid
- dithranol
- topical seroids - photherapy
- oral treatments
emollients used in psoriasis
diprobase
epidermis
E45
mechanism of action tar preparations
reduces DNA synthesis and epidermal proliferation
what drug is dianthrol
vitamin A analogue - anti-mitotic
- should only be used on stable plaque psoriasis
- stains clothing purple
examples of vit D analogues used in treatment of psoriasis
Calcipotriol
Calcitriol
first line phototherapy in psoriasis
UVB
- 3x week for 6-8 weeks
first line systemic therapy in psoriasis
methotrexate
- oral or IM injection once weekly
- regular monitoring of FBC, U+Es, LFTs
what systemic medication can be used in acute severe psoriasis flares
ciclosporin
- side effects include hypertension and renal impairment
