psoriasis Flashcards
psoriasis pathophysio
immune;
- abnormal T cell activity stimulates kratinocyte proliferation
Auspitz sign
small points of bleeding when plaques are scraped off
(psoriasis)
Koebner phenomenon
refers to the development of psoriatic lesions to areas of skin afffected by trauma
plaque psoriasis
commonest subtype
well demarcated red, scaly patches affecting the extensor surfaces, sacrum + scalp
flexural psoriasis
in contrast to plaque, the skin is smooth
guttate psoriasis
commoner in kids + adolescents
triggered by a streptococcal infection 2-4weeks prior to lesions appearing
acute onset over days
multiple red, teardrop lessions on trunk+limbs
pustular psoriasis
palms + soles
extra dermal features in psoriasis
nails;
- pitting
- onycholysis - separation of nailbed from nail (painless)
arthritis
- “pencil in cup” appearance
psoriasis exacerbating factors
trauma
alcohol
withdrawal of steroids
drugs;
- beta blockers
- lithium
- antimalarials - chloroquine
- NSAIDs
- ACEi
- infliximab
step infection may trigger guttate psoriasis
chronic plaque psoriasis
regular emollients, reduce scale loss + itch
1st = potent corticosteroid applied once daily + vit D analogue (apply separately)
2nd = no improve after 8wks, vit D analogue twice daily
3rd= potent steroid twice daily or coal tar preparation
secondary care
secondary care management of chronic plaque psoriasis
phototherapy
- UV B light
- SE = skin ageing, squamous cell ca (not melanoma!)
systemic therapy
- 1st = oral methotrexate (esp if joints involved)
scalp psoriasis management
potent topical corticosteroids once daily for 4 weeks
- no improvement -> diff formulation of the steroids - shampoo, mouse etc
Face, flexural and genital psoriasis management
offer mild, mod potency corticosteroid applied once or twice daily
- maximum of 2 weeks
how long of a break should there be between courses of topical steroids in psoriasis
4weeks
examples of vitamin D analogues
calcipotriol (Dovonex)
- work by reducing cell division + differentiation -> reducing epidermal proliferation
- reduce scale + thickness - not erythema
can be used long term !
avoid in pregnancy
management of guttate psoriasis
most resolve within 2-3months
- no evidence for Abx for step infection
topical agents as per psoriasis
tonsillectomy may be necessary with recurrent episodes
referral criteria for patients with erythoderm or generalised pustular psoriasis
referred same day !
referral criteria for psoriasis
- kids/young people
- diagnostic uncertainty
- cant be controlled topically
- > 10% of body surface
