Psoriasis Flashcards
(10 cards)
What is the general appearance of psoriasis? Symptoms/signs
Sharply demarcated erythematous plaque with micaceous scale
Numerous and small, widely disseminated
Can have erythroderma >80% BSA
Nails can have oncholysis, pitting, oil spots
Scalp signs
Koebnor phenomenon, Woronoff’s ring
What are the risk factors/triggers for psoriasis?
Polygenic dispotion + environmental triggers
35-90% have family history
HLA-CW6 allele > 10x risk
PSORS1-9 susceptibility regions
Infection
Drugs
Trauma
Sunlight
How should suspected psoriasis be investigated?
Clinical evaluation
Skin biopsy if atypical
What are possible differential diagnoses for psoriasis?
Seborrheic dermatitis
Lichen planus
Mycosis fungoides
(Bowens disease, drug eruption, infection, secondary syphilis, contact dermatitis, extramammary Paget’s)
What are some subtypes of psoriasis?
Chronic plaque psoriasis Guttate psoriasis Palmo-plantar psoriasis/pustulosis Scalp psoriasis Nail psoriasis Flexular/inverse psoriasis Pustular psoriasis Erythrodermic psoriasis
How is psoriasis treated?
GP
- emollients - cream vs ointments
- soap substitutes
- vitamin D3 analogues
- coal tar creams
- topical steroids with care
- salicylic acid
From dermatology
- crude coal tar
- dithranol
- UVB phototherapy (guttate)
- retinoids - acritretin
- immunosuppression - methotrexate, ciclosporin
- biologics - anti-TNF (etanercept), anti-interleukin (ustekinumab)
What management should be given in complications of psoriasis requiring hospital treatment?
Fluid balance
Bloods/IV access
Thick greasy ointment emollients
Monitoring - PASI, DLQI
What is the general prognosis for psoriasis?
Good with correct treatment
Men lose 3.5y on average
Women lose 4.4y
What is the pathophysiology of psoriasis?
Due to adaptive immune system
- T cells (epidermal CD8, dermal CD4 and 8)
Stressed keratinocytes
Activation of dermal dendritic cells - present uncertain antigen to naive T cells in lymph nodes - differentiation into Th cells > psoriatic dermic and plaque formation
Keratinocyte proliferation
Cell cycle reduced from 28 days to 3-5 days
What are the histological features of psoriasis?
Hyperkeratosis - thickening of stratum corneum
Neutrophils in stratum corneum (munro’s microabscesses)
Psoriasiform hyperplasia - acanthosis - squamous cell layer thickening with elongated rete ridges
Dilated dermal capillaries
T cell infiltration
